Woodfinishers Weblog

Wood finishing forum for professional finishers

Back painting glass using the CIC Mustang adhesion promoter

Adhesion promoters are a very useful tool to have in your belt as a finisher, as you will see in this very informative video by master finisher and good friend Thomas Craven, of Thomas Craven studios in Van Nuys California.

Back painting glass is what we are doing here, the other uses for this product are where you have to paint  rubber or plastic, this product was originally designed for painting plastic bumpers  and parts for the automotive industry ( Rubber bumpers on cars, 30 years ago that was a joke). Another use is painting over plastic laminates. I had a customer that bought some very expensive custom cabinet doors from Italy, they were a laminate that had a custom wave C-N-Ced in to the door, the customer made a mistake and got the wrong color,  we used the adhesion promoter on these and fixed the color.

Tom is using the CIC mustang adhesion promoter to back paint glass that is going to be used as a black splash, this is a cool little technique and is very popular. It has high tech ultra modern look and is easy to do, getting the paint to stick to the Glass is the tricky part.

An adhesion promoter is in essence a spray on glue that bonds to the glass and then bonds to your paint and thereby promoting adhesion, Simple Right?    yes and no.

There are a few key application points that Tom goes over in the video that are very Key, two light  (underline) coats. this is not a coating in itself you just want enough to get so stick.

NEXT POINT, you apply  your paint while the adhesion promoter is still tackie. don’t let it dry and then paint over it you have defeated the purpose.

The CIC mustang is a great product as it sprays out very light and doesn’t clump or clog, when looking at the glass you wouldn’t know that there was anything other than the color coat, and guess what you can get that product and other fine CIC products on my web site at http://www.annexpaint.com. if  you have questions you are welcome to write to me at info@annexpaint.com.

and here’s the video:

 

best,

Greg Saunders

 

February 2, 2015 Posted by | Conversion varnish, Spray techniques, Tips and Tricks | , , , , , , | Leave a comment

Heating your Lacquer for phenominal results (kremlin in-line lacquer heater)

I thought I had said more on this subject of heating your coatings for better results and perhaps I have, but now time has gone by and the data has been buried somewhere over the years in some article somewhere in my Blog making it not all that useful.

Let me get to the point; when you raise th temperature of your coating, be it water based or solvent you are reducing the viscosity or thickness of the materials. With in a certain range of temperature for every 10 degrees warmer you make your lacquer (be it water based solvent or urethane)  you will make your product 10% thinner. The great aspect about that is that you are not reducing the volume of solids. 

If you thin a coating  50% you’ll have to put on twice the number of coats to achieve the same build. Here in America the labor is your most expensive commodity.  Now if you can raise the temperature of the materials 50 degrees you achieve that same amount if thinning but you would do it with out adding the solvents that will evaporate out and leaving your coating behind.

But that’s not all! In addition to the above the coatings you lay out will flow out better and dry faster. And you can do it with out the expence of Lacquer thinners which are getting expensive.

There are several things you can do to use this data, the easiest is to take your pails off the concrete floor and put them up on wood blocks if nothing else. I have had contractors wrap a heating blankets around their pails and warm their lacquer up that way.  I have even seen finishers put water based lacquers in the Micro wave and warm it up.

Intelligence needs to be used, especially when dealing with flammable materials. Making your materials warmer is the key but I wouldn’t go past the point of heating materials beyond warm to the touch. you can stick your finger in and its warm to the touch Body temperature is 98 degrees so I would say no more than about 104 degrees.  Obviously if your boil your materials you are going to be changing chemical properties. Again, some intelligence please.

With duel component materials you are going to be shortening the pot life. Gradients and testing are key here. I’m a big fan of pushing something to see where their fail point is but not on a customers cabinets, when you are at that point you should have all your procedures all figured out.

Ok, the basics covered,  here are two Video demo’s of Jody Toole using the Kremlin Air-assisted airless spray rig with the new Excite spray gun and the Kremlin materials heater. Jody is a professional finisher in the Southern California area, if you are interested in contacting him you can reach him through his blog at: http://jodytoole.wordpress.com/

In the first clip he is using the rig and in the second he is telling some of the benefits of the whole system. 

And here is the second video Jody describing some of the attributes of the Rig and his review :

For note: the Lacquer that we are applying here is the CIC Coatings Acrylic lacquer I have said so much about int he past.

 Annex Paint sells the Kremlin air assisted airless and all of  its sundries including the heater. If you are in the southern california area and would like a Demo please feel free to contact me.

Greg Saunders
Annex Paint
greg@annexpaint.com
www.annexpaint.com
818-439-9297

February 17, 2012 Posted by | Acrylic Lacquer, Spray techniques, Tips and Tricks, Water based Lacquers, Wood finishing | , , , , , , , , , | 20 Comments

How to finish a wooden sink bowl

This is an interesting one that I thought I would share. A furniture designer from Lithuania wrote to me  asking for help with a wooden sink bowl. I have no pictures to share on this one but after I composed the reply I thought there were a few things in the reply that wood finishers would appreciate.

I have changed the original message from the designed only slightly to protect his identity.

Hello,

My name is Tomas, I am an independent furniture designer. 
Currently I have an order to produce a wooden bathroom sink and it seems that you have some products that could assist me in doing this.
Could you recommend a varnish for such a job (the only requirement is that the varnish needs to be glossy)? From what I understand, the varnish, that would be suitable for a wooden sink, must be hot water-resistant, it also needs to seal the pores of wood well. 
If you have a suitable project, how much water does it let through? Are there any special varnishing techniques? 
Do you have a sales representative in Lithuania? 

Thank you in advance!

Hi Tomas,

Thanks for your inquire; There are two routes to go with a project like this. the first is to use a “food-grade” oil for the proposed sink and instruct the customer that they will have to oil it regularly. This is the sort of coating you have on wooden salid  bowls.
 
For something like that you would have to design it in such a way that it was completely sealed on the bottom and in the drain hole as anywhere you have a penetration or where water is going to collect it is eventually going to make its way into the wood and begin to rot the wood. As a note, I would design the bowl in such away so as to be sure that it doesn’t ever sit in water. For example have it on a metal or plastic pedestal so that any water on the sink counter drains off of it. Standing water will be the enemy you’ll have to overcome.
 
The next problem that you’ll have to overcome is getting a coating that is hard enough to withstand the abuse that a sink will get and yet soft enough to expand and contract with temperature changes.
 
For note: I would never warrantee something like that as the moment someone drops something sharp in the bowl and penetrates the coating you are going to have a place where water is going to eventually seep in and then lift you coating.

The next thing to consider is the wood you are going to use. Ideally I would use the hardest wood you can find; epay or iron wood.

All of the above being said I would then suggest the CIC two component water based urethane.  Or the Permashield 200 from monopole both of these products are good the Permashield 200 is a product that is approved for food servicing areas by the US department of Agriculture (USDA). Both of these you can find on my web site at : www.annexpaint.com

In terms of special application procedures for this application. I would do several things; once the bowl was ready for finishing I would wet it with warm water just making it slightly damp. As you are using a water based product this will not react badly with the coating and in fact what it will do is lower the surface tension of the wood which will allow the coating to soak into all the grain pores. Next I would put down several light coats of the polyurethane that are thinned down as much as recommended and as well heated to about 100 degrees Fahrenheit. This will further reduce the viscosity and allow it to soak in as much as possible. Repeat the coating  with a light but thorough sanding in-between coats as many time necessary to achieve the build you want but with a minimum of  4 of 5 coats. Only the first or second coat need the additional reduction, the purpose of this is to achieve maximum penetration into the wood. Lastly I would let it cure for three weeks to ensure that it has reached its maximum hardness before giving it to the customer.

I’m sorry I don’t have a rep in Lithuania but if you would like to fly me over I would love to come. I haven’t shipped material overseas as it is rather coast prohibitive for customers.

The two companies who might have a suitable product are Renner and Icsam  they are both Italian and have very good materials.

Best,

  Greg Saunders

 Cell:      818-439-9297
Office:  818-344-3000
Fax:      818-344-3994

greg@annexpaint.com

www.annexpaint.com

I wonder if my boss would fly me to Lithuania?? 

 

January 11, 2012 Posted by | polyurethane, Spray techniques, Tips and Tricks, Water based Lacquers, Wood finishing | , , , , , , | Leave a comment

Spray Gun Tip Sizes

The following is the complete article on the subject of spray tip sizes as written by Phil Stevens, I  have received  their permission to reprint this article , Phil is a founding member of AWFI, American Wood Finishing institute, and has trained thousands of people on the Correct technology of finishing, including myself. I took a Finishing course put on by  AWFI out here in southern california and came away from the training very skilled.  If you ever have the opportunity to do their training program it is well worth the investment. This article was taken from Phil’s Blog from the Finishing IQ.com site  http://www.finishingiq.com 

Having toiled over correct tip sizing with different manufactures I stumbled across this article while getting a Kremlin set up for a customer the article answered my questions clearly and concisely so rather than spending the time to re write Phil’s article  I decided to plagiarise it completely  (with permission ) and give the credit where credit was due.

Choosing the correct tip and gun set-up for your spray equipment can be very confusing. The overwhelming number of tip sizes, set-up options and differing nomenclature between the equipment manufacturers often leads to finishing problems as a result of using the wrong size of tip.
U.S. manufacturers often use thousandths of an inch to designate the size of the tip. However, many U.S. manufacturers also use millimeters to classify tip size on some of their equipment. This is especially true when specifying HVLP spray gun set-ups. Other non-U.S. manufacturers use millimeters and other types of nomenclature that does not refer to either millimeters or thousandths of an inch. Here are some of the common nomenclature definitions used for some of the spray equipment manufacturers that are used in the wood finishing industry.

Graco
Graco air assisted airless tip sizes: A “512” tip is read as if the first number (5) is doubled to equal 10, which designates the spray pattern width of a minimum of 10 in. wide at a distance of 12 in. from the end of the tip. The second and third number – or in this example, the 12 – represent the tip opening size as 0.012/in. Therefore, if your tip is a “614” number, it would be a 12-in. fan pattern and a 0.014 tip opening.

Graco HVLP and conventional guns are designated as either millimeter or thousandths of an inch or both on the gun set-up size.

Kremlin
Kremlin air assisted airless tip sizes: A “09 -114” – the first number of “09” designates the orifice opening size of the tip, however, the “09” does not refer to either thousandths of an inch or millimeters. It is a numbering system that Kremlin uses to define the orifice size opening. A “06” number is a smaller orifice opening than as “09”. A “12” tip would be larger than a “09”. A “06” equals approximately 0.011/inch. A “09” equals approximately 0.013/inch. A “12” tip equals approximately 0.015/inch. The second set of numbers after the dash refers to the fan pattern width in degrees of arc. A “114” equals 114 degrees of arc in the width of the fan pattern. Therefore, a “94” will be narrower than a “114”. A “134” will be significantly wider than a “114”.

Kremlin HVLP spray gun nomenclature normally uses millimeters to designate tip sizes. Therefore, a 1.0mm tip will be smaller than a 1.5mm.

Binks
Binks air assisted airless tip sizes: For a “114 – 01310”, the “114” designates a standard flat tip. The first three numbers after the dash (“013”) equals thousandths of an inch or 0.013/in. in this example. The last two numbers, or the number “10” in this example, designates a fan pattern width of 10 in. at a distance of 12 in. from the end of the tip. If the tip starts with a “9 – 1311F”, the “9” and the “F” designate that it is a fine finishing tip with a pre-orifice. The tip would have a 0.013/in. orifice opening and an 11 in. fan pattern at a distance of 10 in. from the tip.

Binks HVLP spray gun nomenclature uses gun set-up numbers that must be referenced from their literature to determine their size. Most often they will be referenced with both millimeter and thousandths of an inch.
DeVilbiss
DeVilbiss standard spray guns, HVLP guns and trans-tech guns use millimeters to define the size of the tip and gun set-up.

What size tip is right for your application process?
Tip sizes will vary greatly, depending on the types of material sprayed, the viscosity of the coating, how much material needs to be applied (flow rate), whether it is pressure-fed, siphon-fed or gravity-fed and whether the application is manual vs. automatic spray.

For very low viscosity spray-to-color stains using HVLP gravity-fed spray guns, a 1.2mm to 1.4mm tip will work well. For pressure-fed HVLP guns spraying spray-to-color stains, a 1.0mm to 1.2mm set-up will normally be the range used for tip size. If you are spraying the same material with automated spray HVLP, a 0.08mm to 1.0mm tip size is recommended.

For spraying spray-to-color materials that are slightly higher in viscosity, such as a shader, an HVLP gun normally will work well if the tip size is increased by 0.2mm to 0.4mm for all of the above technologies.
Wiping stains spray best with air assisted airless technology. We recommend using a 0.06 to0 .094 tip size for Kremlin equipment; for all other manufacturers, a 0.28mm or a 0.009 tip orifice size will be adequate. An 8-in. fan pattern width is an average size for applying wiping stains. Larger or smaller pieces require a larger or narrower fan pattern width.

For solids, sealers and clear coats, an air assisted airless gun is recommended. Tip orifice opening size should equal around 0.013/inch. For Kremlin, this would equal a “09” tip. Pattern width of the tip generally ranges from 6 to 12 in. depending on the width of the parts. A wide fan pattern will often provide a more uniform coat with less runs and sags; however, a narrow tip will ensure higher transfer efficiency on narrower parts. Therefore, an average tip size for Kremlin would be a “09 – 114”; for Graco, a “513”; for Binks, a “114 – 01310”.

For heavy bodied primers and glazes, a 0.015 tip or larger on an air assisted airless gun will generally provide a flow rate necessary for these materials. For Kremlin, this would equal a “12 – 114”; for Graco, a “515”; and for Binks, a “114 – 01510”.

For water-based coatings, use the tip and gun set-up recommended by the equipment manufacturer that is specifically designed for water-based materials. These guns and tips are specifically designed to spray water-based coatings without causing shear on the material. We would recommend that you start with the same tip sizes for solvent-based coating. If you are experience problems with micro-foam or bubbles in the finish, you may need to try a larger or smaller tip on a trial and error basis to insure the best result is achieved with the type of water-based coatings you are using. Not all water-based materials are created equal; therefore, an exact recommendation for these materials cannot be offered.

Conclusion
When choosing the correct tip sizes, always take into consideration the following:
Does the stain have a heavy load of pigment? If so, a larger tip may be required.
Is the stain made with only dye colorants? If so, a smaller tip may be best for this type of stain application.
The solvent package of the coating: what is the solvent blend composition and does the material have a fast or slow flash-off rate? This will influence the tip size and gun set-up.
Viscosity of the coating: a larger or smaller tip may be necessary to most efficiently apply the coating depending on the density of the material.
The speed of spray application: Always try to select the tip that delivers the correct amount of material for the speed of application while maintaining the desired finish quality.
If you choose the correct tip size for the job, your finish will look better, you will reduce rework, will experience of spray operator comfort, and will increase the efficiency of the coating application.

June 16, 2011 Posted by | Spray techniques, Tips and Tricks, Wood finishing | 1 Comment

The Kremlin Air Assisted Airless Spray gun video demonstration

This  is a phenomenal spray gun that I have previously not paid enough attention to.  The great benefit of this tool is the increased transfer efficiency or percentage of materials which are making it to the target. With conventional airless you have about a 60% efficiency meaning that you have lost as much as 40% of your paint to the atmosphere and or your spray booth filters. With the Air-assisted airless the transfer efficiency is about 85 % so you are wasting  25% less of your paint.  This  would mean that for every 100 dollar pail of lacquer you are buying  you are saving  about 20 to 25 dollars. That is a savings that can quickly add up and pay for the rig.

In-essence it is pumping the paint out with an airless pump but it uses two opposing  streams of air to atomize the paint  much like a cup or gravity feed spray gun. With the combination of the air,  less pressure is needed to get the paint out and so more of your paint goes on the thing you are painting and less of your paint bounces off the surface and into the air.

The other benefit is that is applies the materials with less force and so give you a smoother finish, in the following video Jody Toole has been using an airless sprayer but was having some troubles with bubbling on the first coat, this was being caused by too much pressure resulting in the materials foaming when they impacted with the surface of the panel. he solved this by backing down the pressure and holding his gun further away, while that solved the bubbling it gave and even lower transfer efficiency and the material did not flow out as well. With the Kremlin all these issues were resolved.

The cost of the whole rig is about 2700 bucks and that is a little pricy but depending on how muc you spray you’ll have paid for it in savings on materials, which by the way are getting  more expensive by the day with rising gas prices.

For note: Jody is spraying the CIC low VOC acrylic lacquer which is, in essence a cab acrylic on steroids  for those of you that may have used such a thing in the past,  it is 160 gr/lt. VOC,  it is low odor and it won’t yellow.  This is the same product featured elsewhere on the blog that the Church of Scientology’s new Los Angeles and Pasadena church furniture are coated in.

 

I sell the Kremlin so if you are in my neighborhood call me and we can get together for a demo if not you can look them up on-line and find the nearest dealer. There are other companies that have air assisted air less equipment as well.

Since this article Jody has gone off and done a few more video demos and so I though I would add them to this posting  so that you could see some other demonstrations of the rig.


 

I welcome your comments.

best,

Greg Saunders
Annex Paint

April 12, 2011 Posted by | Acrylic Lacquer, Spray techniques, Tips and Tricks | , , , , , , | 12 Comments

Thinning and retarding water based lacquers and coatings

There are a few tips to thinning and retarding water based materials that are common to most all of the water based materials on the market today, knowing these tips can make spraying out water base materials easy fun and most importantly give you the control over the flow of the materials so you  compensate for the varying conditions of your environment.

One of the things to be aware of with water based materials is that they are temperature and humidity sensitive, meaning that on a cold and rainy day it will take forever to dry if left wit out forced air and some heat.

The obvious and wonderful characteristic about water based materials is that you can thin them with water; water is cheap and not explosive.  No one has ever accidentally blown up their shop with a bucket of water.  That being said   you can overthin with water and that can create a mess.

Before we get into percentages and how much you should thin, one thing you should know is that the warmer the materials are, the thinner they will be. This is true of both water base and solvent materials.   Heating pads, bucket heaters and in line material heaters are all things that you can implement.  Inline materials heaters are pricey and not something that are too common here in Southern California  but can be used. More commonly and more practically you can just keep your buckets off the concrete floor or move the bucket in to the office of the shop overnight if it’s cold out. Warming up water base is easier and safer than warming up the solvent materials and in fact with some water base materials you can even warm  them up in the microwave machine, a little impractical but not impossible.  For every 10 degrees you heat the material you will reduce the Viscosity by 10% .  And that is a good thing to know because you can reduce your labor by putting on a thicker coat save our self the labor of having to put on another one of or two more sometimes

Now onto the more practical, the first thing that you should do is adjust your equipment to the material in other words if you have been spraying lacquer with an extra fine airless it’s probably going to be too small an orifice for the water base; you don’t want to overthin it so that you can get it out of  your gun but rather get a bigger tip. Generally a 1.7 mm tip in a cup gun and or something no smaller than a .014 in an airless and that would be the smallest I recommend 1.8 or a 2.0mm tip and needle for a cup or gravity gun.

When you do need to thin the materials down I start out with about 5% water and see how it’s coming out of the gun and laying down, with water based a good heavy coat is what you want if it looks a little blue you are doing good. You want it heavy enough to flow out but obviously not so heavy that  it is running.

Ok the next thing is getting it to flow out and lay down smoothly if it has any orange peel to it then you need some retarder. I generally add the retarder whether I need it or not as I like that fact that it flows out better, this might not be true of all water bases but the ones I have used it just seems to work better with the proper amount  of retarder.

Glycol ether is the solvent for retarding water based material you can also use that for retarding regular solvent lacquers   If you use too much your coating will never dry. The other thing to know is that you can add the retarder too fast and “shock” the material. Shocking information, but true. Dump the retarder directly in to your pot and it can cause itto foam up and have an adverse reaction. Some chemicals go together easily and some don’t;  then there are others that are right on the boarder, this in one of those. So the best way to add the retarder is to mix it 50/ 50 with water first and then add that into the water based lacquer while stirring it. Start out with one to two percent of the   50/50 water retarder solution and see if that doesn’t do the trick for you.  You can go as high as about 4%. If you are working with pigmented water base materials then you can go up to 7% .

White and pigmented lacquers require more and will have a tendency to “mud Crack” (Mud cracking is the phenomena whereas the material dries it begins to crack like mud drying out)   if you don’t use the retarder, what is happening is the solvents are drying out of the pigment faster than the pigment is drying and so you need to slow the process down so that they all dry and flow together.

Not all retarders are the same, some companies sell retarders that are a combination of different things, these work well for solvent lacquers but not always for water based materials.  You either want a lacquer retarder that is made and marked for Water based materials OR you have to test them. The way  you test your normal run of the mill retarder to see if it will work in your waterbased system is to mix it  with water. Simple, if it mixes in you’re good If it separates and doesn’t mix in or foams up and looks weird then its not going to work.  There are a few manufactures that have acetone in their retarder which doesn’t mix well with water If you add that to your water based lacquer its trash.

Ok I hope this information is clear and to the point. Use it and let me know what you get. Leave comments on the blog posting for others to see. I have specifically kept this report completely generic so that if you have a product that you are trying out for the first time it is generally best to contact the manufacture and ask them what they recommend, the better companies will spend the time to answer your questions others won’t

 Thanks,

 Greg Saunders
Annex Paint

February 20, 2011 Posted by | CIC Centurion, water based Conversion Varnish, Spray techniques, Water based Lacquers | , , , , , | 2 Comments

How you apply lacquer to plastic or glass

Lacquer Plastic and or Glass ?? How would you do that?

Simple, use and adhesion promoter, and what is an adhesion promoter you ask. This is a product that has been around the automotive paint industry for sometime, It has made it’s rise to fame in the auto industry with the advent of the rubber bumper. Painting rubber bumpers is a trick as you need something that is going to stick to the plastic be pliable and then match the paint job on the car.  

 That being said the makers of the water based conversion varnish have come up with and excellent adhesion promoter, called “Mustang” The automotive guys seem to love it and I was of the mind that I wouldn’t have that much use for it but Low and behold I has a custom cabinet shop come to me with a unique problem.

Their customer ordered high end cabinetry from Italy and made a mistake on the color so they need the color changed, OK no problem, good work for some finisher but wait the doors are a thermal foil vinyl coating. What do you do? Yup, Use the Mustang adhesion promoter. 

 Two coats sprayed on from an aerosol can let them dry for a few minutes and the lay on your coatings, in this case I was spraying the centurion water based conversion varnish as you can see in this picture.

the use of adhesion promoters for painting plastic and glass

As you can see there is a profile in the panel making sanding all but impossible despite that the paint stuck like glue.  I built this up with light coats but it only took my three light coats to do what you seen here. I used a 1.7 mm siphon feed gun with about 30 psi of pressure, just enough to get the materials to atomize.

 Once the coating was dried if wouldn’t lift or peel. I was able to scrap it off with a knife and even with that it didn’t peel.

 The Mustang and the Centurion water based conversion coating are available from my store as well as will be available on line at  http://annexpaint.com web site soon.

 Greg Saunders
Annex Paint

July 7, 2010 Posted by | CIC Centurion, water based Conversion Varnish, From the Chemist, Spray techniques, Tips and Tricks, Uncategorized, Water based Lacquers, Wood finishing | , | 3 Comments

Renner Acrylic lacquer -Tips for scuccess

 

This is a brief write-up from a finisher who has been successfuly using the Renner Low VOC Acrylic Lacquer

Dear Greg,

 As you requested I’m giving you a little write up on the Renner Low VOC Acrylic lacquer from that you have been supplying to me.

 I have been using the Renner Lacquer and really like this product.

 I wanted to detail some of the basic procedural points I employ when using this product that may help other people who use it:

  

  • I generally only need 2-3 coats of the Renner to get a beautiful finish. 2 coats are most common if you don’t thin the product. The product does not need to be thinned. I have thinned the Renner Acrylic lacquer but only on the final coat if you don’t wish to have any further build up than what I already have on the piece I am spraying. You shouldn’t this this any  more than about 5% per manufacture’s specs any way.

 

  • The key to spraying a good finish is having your gun set properly based on your spraying conditions ( mainly temperature and size and shape of the item you are spraying .) I generally have the PSI on my gun set between 20-40 no more than 40 psi. Then watch your spray in reflected light as you are spraying to ensure you have a wet coat over your whole job.

 

  • I have found that the Flattening agent in the Renner Lacquer tends to settle rapidly to the bottom of the can or spray gun. I have picked up a gun that I had sitting with the renner Acrylic lacquer in it for a few hours and sprayed it and the first thing that comes out is the white flattening past that has settled to the bottom of the cup. A light sand and then re-spray with the same product handled that for me. I have also had spots of white spit out of the gun these are just the flattening past that settled. You have to let the lacquer dry and then sand then off and re- shoot it. The over all handling is to stir and strain the materials well and then don’t let your gun sit for too long. If you use a pot system then stir the pot regularly. Shaking the materials well before you use them is also a good Idea. The flattening past goes back into solution very easily.  

 

  • I always test spray something before I lay on a coat and especially the final coat; I want toknow that the gun and materials are all dialed in before lay the materials on the final coat.

 

Hope this is helpful.

Tia D

 Tia has worked in a custom mill that produces a wide Varity of custom mill work that has been shipped and installed around the world. She has been applying high end finishes for about 4 years and is one of the best and most detail oriented people in the trade. I asked here for this little write up to help other customers with this product.  

  In addition to Tia’s Tips I wanted to add a few other characteristics about this material that I have found about it.

  •  This is an acrylic lacquer, the qualities of it are that it doesn’t yellow and it is nearly as hard as a Catalyzed lacquer, however, you can’t mix it with regular nitrocellulose lacquers. You have to keep these materials separate and do not mix them.
  •  You also don’t want to use this material over another lacquer it is self sealing and is used with it’s self spray in a light coat and lat that flash off and then your following coats to the desired build. You can glaze between coats.

 

If you have questions or comments send me a line I’m always interested in hearing what people are running in to.

 Best,

 Greg Saunders

Annex Sales Rep

greg@annexpaint.com

July 1, 2009 Posted by | Acrylic Lacquer, Finishing failures and the fix, Spray techniques, Tips and Tricks | , , , , , , , | 2 Comments

Spray Finishing Basics

Spray Finishing Basics

by

Thomas Craven

 

All spray systems attempt to achieve one thing, that is atomization. Atomization from the dictionary is to, “reduce to minute particles or to a fine spray”. Whether you chose conventional, HVLP, or airless spray equipment, they all achieve the same thing; that is atomization. A satisfactory finish is produced when the spray material is atomized to the point that the material will flow onto the surface and become a uniform and even coating.

 

Viscosity and pressurization are the two main factors that effect proper atomization. 

 

I looked up the definition of viscosity in the dictionary and found it to be just as hard to understand as the name itself. So I will tell you my definition of viscosity as it relates to spray finishing. Are you ready for it; it’s how thin the material is! Correct atomization occurs when the material being sprayed is just viscous or thin enough that the pressurization provided by the spray equipment in use can break up or vaporize the particles to produce a satisfactory coating. You only thin the material down enough so that your spray equipment will atomize the material while producing a coating that flows out onto the surface. Thinning the material too much will leave a coating that is spotty and runs down vertical surfaces. A coating too thick that is drying to fast will give you dry, rough areas and orange peel.

 

Now that we have our material correctly thinned how do we then atomize it? By pressurization. It is the air under pressure coming out of the front of an air gun that breaks up

 the material. Or in the case of airless spray equipment, it is the pressurization of the material itself in the spray line that is then forced out the front of the gun through a very small orifice or spray tip that causes atomization at the front of the gun.  

 

Spray Equipment

 

Conventional– High-Pressure, Low-Volume air spraying is out dated technology. Rarely in use in California any more. Produces a lot of overspray and hence wasted material. Material is presented at the front of the gun where air ports in the air cap at the front of the gun introduce a low volume but high pressure, (40 – 60 psi.), stream of air into the material to break it up and create a variable fan pattern.

  

HVLP– High-Volume, Low-Pressure, is the standard equipment in use today in California. It atomizes the material in the same manner as the conventional gun, by introducing a stream of air into the material that is presented to the front of the gun. However HVLP guns use a larger volume of air at a lower pressure typically 10-20 psi. Reversing the relationship between pressure and volume. This system decreases voluminous overspray and saves materials.

 

Compressors and Filters. Both of these spray systems need compressed air to operate. This air should be filtered as the action of compressing the air heats it up. While in the tank and hose, this air cools down. The moisture in the air then condenses in the tank and lines. In addition compressors will inject oil and other contaminants into the air supply. An oil and water separator / filter mounted close to the end of the airline is recommended. The compressor should be installed outside the building whenever possible. Remember it will be drawing air from the surrounding area you install it in and blowing it on your work. 

 

Spray cups / guns and spray pots.

 

A siphon cup gun has a one-quart cup attached to the bottom of the gun. When you pull the trigger on the gun, air is released out of the air ports in the cap at the front of the gun. This air stream siphons / pulls material out of the cup. The vent hole at the top of the cup must remain free and clear to allow air to enter the cup so that the siphoning action can take place.

 

A gravity feed cup gun is a new innovation in cup / gun design. The cup is mounted above the gun so that the force of gravity is used to bring the material down and present it at the front of the gun. You must keep the vent hole at the top of the cup free and clear to allow the material to drain into the gun. It is superior to the siphon feed cup gun design. Both siphon and gravity feed cup guns are best used for small amounts of material. Sample work, shading and toning procedures, etc.

 

A spray pot is a two-gallon or sometimes five-gallon pot or bucket that has a pressure regulator attached to the top of it. The regulator allows air to free flow through to the gun to atomize the material, but it also pressurizes the material in the pot. Instead of passively siphoning or allowing gravity to feed the material to the front of the gun, the spray pot will deliver material under pressure to the front of the gun for atomization to take place. This will allow greater production as less air is needed to atomize more material. In addition greater capacity is provided by the two or five gallon quantity of material in the pot.

 

Airless spray machines use a hydraulic pump to pressurize the material that is sucked up in a pick up tube from a five-gallon bucket. The material travels in a ½” diameter spray line that are available in fifty foot lengths. The material is forced out the front of the gun through a very small orifice or spray tip. This spray tip atomizes the material and shapes it into a spray fan of preset widths 3 to 21 inches wide.

 

 

The big advantages to airless spraying are,1. Dispensing with the need for compressed air to atomize the material. You get straight material coming out of the gun without the cold, damp, dirty air that is delivered by most compressors. 2. A uniform spray pattern delivering a consistent amount of material all the time. This spray pattern does not require constant adjustment like the conventional and HVLP guns do. 3. It is a closed airtight system so that you may leave material in the spray rig and bucket for extended periods of time. 4. Only one material line too the gun allowing for more mobility. Excellent choice for high production shops.

 

Spray Techniques

 

Spray finishing skills take a lot of raw gun time to be proficient at. You can speed this process up with proper training and coaching. A very simple concept I express to my spray man trainees is; Spray until the surface just gets wet, no more and no less. If you spray too dry, the material won’t flow and will be rough. If you spray too wet, it will and run and fall down vertical surfaces or pool and puddle. Your goal is to get the material to flow and become one even uniform coating with no orange peel, dry spots, runs etc.

 

Always start from the up wind end of the work and spray away from you towards the face of the booth. You don’t want to spray into the airflow of the spray booth as this will leave overspray on previously finished parts and the spray man too. Shoot all edges first and try to shoot your best surfaces last. Cabinet boxes should be shot from top down, working from inside out and horizontal bottoms last.

 

Lapping the material. The general rule of thumb is to overlap your spray pattern by 50 %. This is not set in stone. It can vary depending on the speed you are moving your spray hand. Just remember the basic principal. Spray until the surface just gets wet, no more and no less. Be sure to overlap the leading and trailing edge of a panel to apply a uniform coating to the edge.

 

Six to eight inches away? Again this is a rule of thumb that is not written in stone. Hold the gun the distance from the surface that produces a coating that is just wet.

 

Watch the material coming out the front of the gun. Don’t watch the gun or the surface you are spraying. Keep your eye focused on the material flowing out the front of the gun. This technique gives you a better perspective on how much material is being deposited on the surface.

 

Samples

 

To live or die by your sample? Variations between samples and finished product are to be expected in natural materials that are assembled and finished by hand. This is a concept that your clients need to understand. It should presented in an educational manner so as not to offend or lead the client to believe you will not try your hardest to achieve the look represented by the approved sample. Variations in color and sheen of finish occur do to variations in natural wood colors, variations in porosity of different wood species, changing lighting conditions, etc. You should express to your customer that every effort will be made to achieve the overall effect depicted by the approved sample. This effort is what differentiates between custom finishing and factory produced assembly line finishes.

 

Stain Finishes

 

Surface Prep – Filling nail holes and minor defects with solvent-based filler is the first surface prep step. You want to leave as little putty on the surface as possible as the filler is hard to sand. The entire surface should now be sanded with 180 grit sandpaper to remove residual putty, dirt, pencil marks, fingerprints etc. I recommend no fill paper as opposed to garnet. If your milling department is leaving too many saw and milling marks in the material, it should be improved. The milling department should be providing the finish shop with stain ready material.

 

Stain Types and Their Uses. The two types of stain we will discuss today are oil based and water based stains. The basic difference between the two will be in appearance and safety. Water based stains and their related finishes are generally milkier or waxy looking compared to oil based stains. However the water-based stains are safer to handle and are more environmentally friendly, as they have no harsh solvents or oil in them. Oil based stains and their related solvent borne finishing systems will produce very transparent and clear stain finishes. Stain rags should be soaked in water in a closed container and disposed of according local regulations.

 

Out Of the Can or Custom Mixed? Use out of the can stains provided by your supplier when ever possible to save time and maintain uniformity between samples and finished product. Mixing stains between stock out of the can stains to achieve a specific color is the next step in providing a custom color for your client. If you desire to take the next step in providing your clients with truly custom colors, you can dive into the world of custom mixing concentrated pigments into the appropriate stain bases. This process requires an understanding of color theory and how the basic ingredients relate to each other.

 

To stain or to glaze? That is the question. Stain open grained woods like oak, birch and ash to achieve a more natural and transparent look. Glaze closed grained woods such as maple, cherry, pine and fir to prevent blotching and promote color consistency.

 

Water based stains on raw wood tend to be blotchy and raise the grain. It is recommended to either glaze the stain over the sealed surface or spray shade the stain on the raw surface with the spray gun and leave it alone; that is no wiping.

 

Glaze is stain medium that is hand applied, “glazed”, (with brushes or rags), over and in between finish coats. This is what differentiates the glazed, finish from a stain that is applied to the raw wood. This finish is typically applied to softwoods or closed grained woods such as, pine, fir, maple and cherry wood. “Glazing the wood”, provides maximum color control and prevents blotching. In addition glazing naturally highlights all details and distressing and creates that warmly aged patina exhibited by fine old furnishings and cabinetry.

 

Sealing – A sanding sealer is usually the same material as the finish with the addition of a sanding paste added to it. It is a slippery soap like substance that allows for easy sanding of the surface in preparation for the topcoat. Some finish coatings like polyurethane will seal themselves with a thin first application. (Demonstrations)

 

Prep for Top coating– Sand with 220 or 320 grit sandpaper. Rub with red scotch brite.  

 

 

 

Top Coating – We will discuss three types of finish today. Lacquer, conversion varnish and water borne lacquer.

 

Solvent based lacquershave been the standard of the furniture and cabinet finishing industry for years due to their excellent clarity, ease of use and versatility. In California they are slowly being phased out as the SCAQMD has deemed them to have too many polluting compounds in them, (volatile organic compound or voc). In addition as they have decreased the voc’s in these products they have become harder to use and not as durable.

 

Conversion varnishis the finish that I am most excited about recently. It is essentially a catalyzed varnish that offers the ease of use of lacquer while eliminating the number of coats applied to achieve the same film depth and appearance of lacquer. My standard eight-coat lacquer finishing process has been reduced to four coats of conversion varnish. In addition as this is a catalyzed finish it offers superior wear and tear and durability. This product sprays and dries almost like a lacquer but has the build and full-finished look of varnish. It is voc compliant.

 

Water borne lacquer is the finish that we will be demonstrating today as it is the material that is used on a daily basis here at the Closet Factory. The paint industry has been continuously improving this product since the late eighties when the SQACMD pronounced that they would be slowly phasing out heavily voc laden finishes i.e. solvent borne lacquer. Many furniture manufactures and other heavy users of solvent based finishes relocated to Mexico and other U.S. states with less regulation during that time. Today some shops are returning and new shops are opening due to improvements made to these waterborne finishing systems. This is a superior product compared to what was available ten years ago and will continue to improve. The advantages of this product are, its very low voc content allowing shops in California to use this material virtually on an unlimited basis. The use of synthetic acrylic resins in this material yield a very durable non-yellowing finish product. In addition due to the minimal evaporative solvents in this material you need less applied coats to achieve an acceptable finish as compared to solvent borne lacquer. The primary disadvantage to this material is the drying time that is still slow compared to faster solvent borne finishing systems. The higher the humidity the slower the drying time. This slow drying time can be improved with warmer, dryer air ventilated through the shop. Heat lamps can be used for work that needs to be finished very quickly. Another disadvantage is the slightly milky or waxy appearance of the final finish detracting from finish clarity.

 

Paint Finishes

 

Essentially all of the information provided pertaining to stain finishes as far as surface prep, priming, (which is basically the same step as sealing), prep for top coating and top coating are the same for painting. The materials are essentially the same with the addition of titanium dioxide and pigments to provide the color and hue.

 

 

Touchup

 

For holes, scratches and minor defects, I use colored wax sticks and putties that are available from furniture finishing suppliers. For larger repairs it may be less expensive to simply replace the part instead of spending hours on repair and touchup that may never be acceptable to the client anyway.

 

Minor color touchups can be performed with colored dye stain markers available from furniture finishing suppliers and art stores. My most often-used touchup marker is a black Sharpie pen. Dab the pen onto the area to be touched up and quickly rub it out with your finger to blend into the surrounding surface before it dries. For touchups that require more than what a marking pen can provide; I use straight concentrated Universal Tint Colorants, (UTC). The dry powder touchup kits that are available are great but they are expensive. I use the UTC stain pigments because I stock them any way for the custom mixing I do. In addition they are ready to apply straight out of the can, thinned with a little paint thinner or naphtha if necessary. 

 

Feather outthe area to be touched up with 220 or 320 grit sandpaper. If you leave a sharp, distinct line between the raw wood area and the adjacent stain it will be very difficult to blend that new touchup into the existing stain color. To feather the area you must sand the affected area until the underlying raw wood color graduates slowly from the raw wood color into the fully stained surrounding area.

 

Start applying colorthat is lighter than the surrounding color. Pad or stipple the color onto the effected area. Simply brushing color evenly onto the surface is usually ineffective as it appears like a paint smear. Padding and stippling the color on diffuses the color onto the surface. You want a slightly busy application that will blend the touchup into the surrounding area. Allow to dry for a little while then apply a couple of coats of finish. Apply your final color to blend in with the surrounding area again padding and stippling as necessary for texture. Apply finish. Rub out and polish to remove overspray and blend finish.

 

Standard rub out materialsare 0000 steel wool with a good quality furniture cream or polish. A lot of polish and light rubbing is usually enough. If the 0000 steel wool produces a sheen that is to shinny try 00 wool; be careful not to rub too hard or you may remove your touchup. Buff with a clean rag. 

 

Reference Materials / Trade Magazines

 

Professional Refinishing is a new free trade magazine. I have been impressed with the quality of the articles. (81 8) 715-9776 / www.prorefinishing.com

 

PWC / Painting and Wallcovering Contractor is another free trade magazine that has good articles once in awhile. (314) 961-6644 / www.paintstore.com

 

Finishes and Finishing Techniques and More Finishes and Finishing Techniques are two books that are compilations of articles published in Fine Woodworking, another trade magazine with some great articles in it. ©

 

Thomas Cravens Shop address

15746 Arminta Street · Van Nuys, CA 91406

Cell # (805) 341-7713 · Fax # (81 8) 908-8061

Email: ThomasCraven@msn.com

Web Site: TCWoodFinishers.com

© November 2008 by Thomas Craven ©

 

 

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January 12, 2009 Posted by | Spray techniques, Tips and Tricks, Uncategorized, Wood finishing | 1 Comment