Woodfinishers Weblog

Wood finishing forum for professional finishers

The importance of clean air for your wood finishing

Just when you think you know it all, you learn something new. Truthfully, once you get over the notion that you know it all the learning really begins.

Experience is a great thing and is something  you gain after putting in your time, But true wisdom is always keeping and eye out for what more there is to know about something and how might things be done better.  With that bit of wisdom I’ll tell you about having clean air in your wood finishing shop, something that I have recently gotten a greater appreciation of.

Clean Air does several things for your finishing, all of them good,  dirty air is a combination of three things.

1. Oil,
2. Dirt,
3. Water or moisture.

Oil can come from your compressor or from oils in the air  the compressor suck in, Likewise, Dirt comes in to the compressor or can be from the compressor, little metal flake from the inside of the tank or little rubber from the hoses that need to be replaced. all of these things can land in your finish and screw it up making you have to wait for it to dry sand it down and then reshoot it. Added time and lost money.  Lastly water and moisture, comes from the condensation of the air when it is compressed and
un-compressed and is something that you will always have a degree of, more in the colder humid months.

In the automotive industry and when spraying urethanes and high-end finishes this is vital as the tiniest amount of moisture will ruin a finish. In the wood finishing industry the importance of clean air is often not stressed enough.  but that being said when you start getting over 15% humidity in your air you clear coats won’t dry as quickly and wont be as hard or as clear. If you look at a clear coat that is cloudy under a microscope you’ll thousands of tinny bubbles  that are quite often  water drops that were trapped inside the finish,  With water based products you can get away with more humidity but despite that all of your coatings water base or otherwise will dry faster and harder when you have decreased the humidity below 15% for the high end automotives you want to be blow 5%

There is another benefit to having dry air and that is your air tools will last longer.

We installed the RTI PERF 50 system in Thomas Craven’s wood finishing studio and here is a video of him telling you what the system does and how much it has improved his finishing.

The Perf 50 system is great unit designed to handle the air flow of a two booth shop.  there is a smaller unit for a single booth application and you can go with less expensive systems than these. minimally you want to have a three stage system that removes oil, water moisture and dirt. the oil and dirt filters are sometimes combined.

I ‘m now certified by RTI to do air quality testing and have the tools to come out to a shop and test the air to see how much moisture and dirt are coming out of your hoses.

If you have any questions about the matter please feel free to send me an email or leave a comment. In the coming months I start having RTI parts and equipment on the annexpaint.com web site for sale.


Greg Saunders

February 6, 2014 Posted by | Finishing failures and the fix, Spray techniques, Tips and Tricks, Uncategorized | Leave a comment

CIC Coatings Water based Conversion Varnish test

I apologize for having been remiss in my blogging duties it has been a busy year. I have a new camera and as well some new things to share.

I went back to a job that a customer did a year ago to see how the CIC acrylic coatings were holding up. In general the CIC 3022 Acrylic lacquer was doing great, on verticals and in bookshelves it looked great. however on counter tops after a year of being in side of a well attended church there were some signs of wear. Jody Toole of Jody Tool’s finishing started to do some tests to see what he could apply that would be harder yet easy to apply and yet not change the color or appearance.

the following video is the test that he did. for reference in the test he used the CIC acrylic lacquer, a 550 VOC pre-cat from mohawk and the CIC coatings water based clear Conversion Varnish. all of the panels were sealed with a vinyl sealer first. He them wiped them down with an lacquer thinner on a rag to see how fast the coating would degrade.

Additional note: although it is not shown here Jody did a separate test where he applied the water based conversion varnish directly over the acrylic lacquer and it looked great and stuck well.

If you are interested in knowing more about these products give me a call.

Greg Saunders
Annex Paint

December 6, 2012 Posted by | Acrylic Lacquer, CIC Centurion, water based Conversion Varnish, Conversion varnish, Finishing failures and the fix, speciality finishes, Water based Lacquers, Wood finishing | Leave a comment

I’m new to the Finishing Game and have questions

The following are a few questions sent into me by a new finisher  I am posting with his permission.

Hi Greg

I am new to this spraying game and wondered if you could let me know what flash off means, also I’m using Sayerlack Hydroplus: waterborne clear self-sealer and so far so good, the finish is great, though i am working in a cold barn with a home made spraying booth and even though I have extraction and filters I am finding particles on the finish. Also what is a good grit to sand in between lacquer coats?

Hi Loukas,
Ok, the term “flash off” is the term referring to the solvents evaporating generally used in reference to solvent based coatings but does in fact apply to water based materials, the solvent being water.

There is the first period after you have sprayed something; its wet, and the solvents are evaporating, i.e. its drying. After that point the coating continues to dry but at a much slower rate. That first stage is the time the solvents are “flashing off”. After that point it might be dry to the touch but still soft. In essence the top layer of the coating has dried but the deeper layers are still drying. Most all coatings dry from the top down unless they are epoxies and urethanes that dry internally with a chemical reaction caused by mixing a part A and B.

Water base materials generally dry slower than solvent based materials but will dry even slower in cold or humid conditions. To speed things up you do two things; heat your materials and or heat your spray area. As you are using water base materials you don’t need to worry about having explosion proof heating (which is something you do have to have when spraying solvent based lacquers.) heat and low humidity with air flow will dry your work faster. That it is drying so slowly makes it more susceptible to dust landing in the still wet finish.

You can also heat your lacquer. For one, don’t store it on the cold concrete floor over night. Minimally keep it off the ground. Warm it up before using it by sticking your gallon pail in a tub of hot water. Or wrap a heating blanket around the can. There are more expensive fluid heaters that heat the liquids as they are going through the hoses to the Gun, Those things are for the pro shop that you aren’t going to need for a while (you can look up fluid heaters or pail heaters on sites like Grangers, Northern tools, and Mc Masters-Carr)

 Just getting your water based materials above room temperature is gong to make a significant difference in the flow out and drying time of you work. Cranking it up to about 98 degrees and you’ll see a finish like glass. When you start heating up the materials that much however you need to have the ambient air temperature and the work piece temperature relatively high other wise your hot materials are going to start pulling moisture out of the air and that will cause you finish to have a slightly milky appearance, which in essence is moisture trapped inside the coating.

Ok the next question: what grit sand paper should you use in-between coats, good question. I use 220 silicone carbide paper 220 is the grit you need much higher than that and you are wasting your time. the silicone carbide is a great paper as the tiny little particles that make up the sand in the sand paper break down evenly so you get and even scratch. There are other fancier papers, Abernete and garnet some people thing there the best others don’t. The other thing you can use is a scotch bright pad there are several different brands 3M makes a few and Mirca (another abrasives company makes a few)

Hope that helps, send me some picture of your operation in exchange for the free advice I would love to hear how it all turn out.

I’m going to post these conversations for others to view, if that’s ok with you.

Best of luck,

Greg Saunders






November 25, 2009 Posted by | Finishing failures and the fix, Tips and Tricks, Water based Lacquers | 3 Comments

Bubbles in the finish

The following is a problem a follower sent in as a question, while it may be long I thought I should publish the diolog for all to have the benifit of: 

I am posting his question with out contact information for his privacy


From: Antonio  
Sent: Sunday, August 23, 2009 7:10 PM
To: info@annexpaint.com
Subject: needing advice and supplier


Hey guys,

We are a medium sized kitchen manufacturing firm based in the Bahamas.  Stumbled across your forums while looking for advice in solving some problems we are having which also haves us seeking new suppliers for professional finishing products.  Can you offer some input on the following problem?
For most of our darker Cabinetry finishes we stick with basic MagnaLac finishes, working from oil based stains to lacquer sealers then on to lacquer clear coats and the only problem is the occasional white cloudiness that is a pain in the a** to get out, usually this is when we spray in cooler weather, right now we still spray outdoors and have our drying racks indoors.

Now here is where the problem comes,  for our lighter colored cabinetry we stick with waterborne clear coats (minwax polycrylic) over water based stains with no problem but lately we have been trying to use the same clear coat system over waterbased paint.  For some reason we get constant bubbles.  We do everything by the books,  lacquer based (pratt & lambert) white undercoater, 2 coats of water based (benjamin moore) paint then after 24hrs of drying,,, the clear coat,,, and the BUBBLES!! We thought maybe it was reacting to the lacquer primer underneath so we re-prime with water based primer then final coat but still bubbles!! We use a basic compressor system with a devilbiss siphon gun (1.7mm nozzle). 

I know polycrylic is not exactly pro stuff but being a small island we are veryyy limited to the products we have access to, and would have to spend alot on importing tons of different products to test.  What do you think is causing the constant bubbles?  We spray polycrylic straight out the can.

any input would be appreciated.


Here was my reply:

Hi Antonio,

 Thanks for the data, that’s and interesting one, Bubbles come from a number of things usually it is because it is too hot and the top most layer is drying faster than the bottom of the layer which is still off gassing and so you have a gas trying to come through a layer of almost dry material which then forms a bubble.  The common solutions is to use a retarder or spray when it is not quite as hot. Out here in California there are a number of shops that do there spraying at 4 in the morning.

 You might want to try thinning the material down with what ever the manufacture recommends, sounds like just water will do, the next thing is getting a retarder for the material. I have found that regular Lacquer retarder works well as a retarder for water based products. That however is not a manufacture recommendation and would be something you would want to test first. Best Practice is to use the retarder the manufacturer recommends. As a point when adding a retarder to a water based material you should mix the retarder 50 /50 with water first and then add it to the lacquer. And you would use more than about 4% retarder other wise you are

 The White haziness is a similar thing, Moisture entrapment. As the lacquers is evaporating it is cooling down the surface and condensing the moisture in the air which them is trapped in the coating. You can do a few things for that, again adding retarder, or you can heat your materials i.e., the lacquer or you can move into a climate controlled space (sometimes not possible)

 Another thing that can cause bubbling is air pressure too high on your guns, another is a that you have seal leak on your gun on the fluid side that is letting air in to your fluid mix and frothing it up in the can. That doesn’t sound too likely.

Let me know how that goes and if you can send pictures and I’ll post it.

 If you want me to ship you materials I can do that.

 Greg Saunders

August 25, 2009 Posted by | Finishing failures and the fix, polyurethane | 4 Comments

Finishing failures and their fix

This page and category is going to be dedicated to the disasters that we as professional finsihers have all had, seen had to fix, and have heard about. I think the point here is to give others a heads up and possibly avoid  the shoals that various projects have run aground on.  I have found that most failures have come about from not knowing or not understanding  the basics of what you are doing. Too many times I have had “Do it yourselfers” come in with the attitude that there is noting to the business and it simple as pie. Finishers just charge and arm and a leg for nothing. 

It is simple and the fundamentals are fundamental but you have to know them and it does take a certain amount of skill and practice, to add to that, the materials are changing all the time and what preformed one way last year has now been reformulated to be compliant now preforms slightly differently. After a Do it your selfer has had a little trouble and has seen what it really takes to do the job they tell me they would have prefered to have paid a professional. That being said you can learn the trade and it can be rewarding. Just don’t set your self up for a loss by walking into the business arogent and uninformed, thats like a  virgin making an incausious  visit to  a military brothel.  the out come is not going to be pretty. 

I have more things to add to this catagory  but I would be interested in your comments and your failures send pictures if you can and we’ll post a few light houses to save others the disasters that we have had to weather.


Greg Saunders

August 25, 2009 Posted by | Finishing failures and the fix, Uncategorized | Leave a comment

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.


 Greg Saunders

Annex Sales Rep


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

Acrylic Lacquer: A new, low voc clear coating for wood.

    No two finishing lines are exactly the same. Nor are the finishing standards or production goals identical from facility to facility  or shop to shop. To satisfy a wide range of variables relating to application, curing, finish durability, appearance, environmental requirements, “green” sustainability initiatives, and cost, I have been on a constant search for the different coatings out in the market.  To this end we have brought in yet another product for our customers to use.


   First of for those who may not be  familure with some of the other products that are generally use in the world of finishing to day.


   Nitro cellulose Lacquer, the basics.

Nitrocellulose lacquer is made by mixing fast-drying solvents generally know as lacquer thinners with wood and cotton pulp containing cellulose that has been broken down by acids. A chemist working for the DuPont Chemical Company, is credited for inventing nitrocellulose lacquer in 1921. It was quickly picked up by Henry Ford for his mass-produced automobiles because finished cars could come off the assembly line faster. Not long afterward, nitrocellulose lacquer replaced shellac and oil-based varnishes and became the preferred finish and the industry standard for furniture and cabinet manufacturers.
: nitrocellulose lacquer is relatively inexpensive and dries quickly. The cured resins provide a reasonable protective layer of film over the wood. After the hard film cures, it rubs out well and provides it signature  smooth and silky surface that, Also, because it is an evaporative finish, each new coat of lacquer blends into all the previous coats, making it easy to repair.

The benefits for large and small production shops are considerable

The disadvantages to using nitrocellulose lacquer are also notable. The film yellows as it ages, and it can eventually shrink to the point of causing cracks (often called crazing) to form in the surface. Generally this occurs when you have over built the coating. As well, it does not hold up well in moisture i.e. your kitchen and bathroom.  Best results fore application are by spraying it on; but the overspray is highly flammable. (The same ingredients that go into nitrocellulose lacquers are also used in the manufacture of some explosives.)

Because it dries so quickly, when applied under conditions of high humidity, the lacquer film can trap condensed moisture and cause the finish film to appear cloudy — a problem referred to as blushing. You can overcome that finishing obstacle by adding a slower-drying thinner, called a retarder, which allows the moisture to escape before it gets trapped in the film.


  The need for something that doesn’t yellow and has a greater moisture tolerance.


Acrylic lacquer


  With the increased popularity of using unstained, light-colored woods (such as ash, birch, and maple), woodworkers and furniture manufacturers wanted to avoid the yellowing problems associated with nitrocellulose lacquer as it ages. The finishing industry responded by developing lacquers containing acrylic resins that are truly “water-white.” Acrylic resins go on crystal-clear and stay that way over time. The most widely used of these products is called CAB-acrylic lacquer, made with cellulose acetate butyrate and acrylic resins.: it is best applied by spray equipment, diluted with regular lacquer thinner to obtain the ideal spraying viscosity, and it is fast-drying. Acrylic lacquer is often used as a protective topcoat over colored pigment lacquers to make them wear better and to enhance their resistance to scratches.

Acrylic lacquer dries to a less brittle and more flexible film than that of nitrocellulose lacquer. It is also more expensive. Otherwise, the working properties are much the same


The acrylic Lacquer I like:


Renner the Italian wood coating manufacture has long provided me with exceptional water based products wanted to get into the American nitro cellulous lacquer market and released their “JL” series 161 VOC acrylic lacquer. Why they had to go and name it like that is beyond me, I would have preferred a snazzy marketing name that I could refer to it as, but, oh well.


Here are the qualities of this product:


Low VOC, more environmentally friendly and you can reduce it and still be compliant; a word of caution though, over thinning it has caused problems. Suggested total amount you thin it is not more than 5%.


Low Odor, It does have a smell but it’s not half as bad as other products.


Self Sealing, You don’t need a different product to seal this with. Best practice is to lay down two thin coat and then sand it as if it were a sanding sealer.


Non-Yellowing, what else do you say this doesn’t yellow as any regular lacquer or Pre catalyzed lacquer will.


Dies Quickly and Hard, I have had a hard time digging my nails in to this stuff, so it is almost as hard as a pre-cat if not harder. As well the acrylic is much more UV resistant,


18% Solids, this is a term that a lot of people don’t get but is a very important datum when evaluating a coating. Basically it’s thicker and so you get more square foot coverage. For reference the most common lacquer on the market is 11% solids it’s cheaper but you have to spray twice as much. For most shops there labor is more costly than there materials and so the few buck you save on materials ultimately cost you more in the long run.  



Cautions I have found:


Don’t over thin it. With a lacquer thinner, you can thin it 5 or 10% but not beyond that it will blush and do strange things. In essence when you thin some materials you are trying to increase the viscosity and make it come out of your spray gun better. If you over thin it you begin to alter the chemical make up and that is where you get into problems.


Don’t apply it over another manufactures sealer. A, you don’t need to use a sealer and B, the acrylics are not compatible with the lacquers when you do this the nitro-cellulous  in the earlier coating get re-wetted and then reacts with the acrylic resins and does weird stuff.


I now have several large manufactures using this product and having great successes with it.


If you are interested in this product give me a call if you have had successes or failure with this product I would like to know about them. One of the things I have learned in this business is that you test always. The greatest test of a coating is the test of time. How long did it last and where?









April 22, 2009 Posted by | Acrylic Lacquer, Finishing failures and the fix | , , , , , | 65 Comments

a few things to be aware of when using waterbase finishes

I have just come  from a mans house who recently refinished his kitchen cabinets, he wasn’t a professional finisher when he started the project but was interested in the game and had the spirit to jump in and figure things out. He came into the store and asked for a water based material as he was going to be doing this work in his house and garage while the family continued their daily lives. choosing a water based material was a correct choice.

The gentleman was friendly, enthusiast and good spirited but not at all familiar with the trade so I told him that if he were to have any trouble to give me a call. Sure enough Saturday morning I got the call. He was having troubles for sure but they were easily resolved with the right spray gun that I lent to him from my collection.

Having the right size gun is essential with water based materials a 1.7 mm tip or a 2.0 is what I prefer.

Now then, all went smooth from there on out until his wife got a little glue on the surface of the finish and tried to take it off with 409 and a rag. To her great shock she took off the glue and all the finish right down to the bare wood. That was the living end, after all that work! the wife was in tears, the husband was in despare after all that work and both decided that the sales guy was going to have to be shot for this grieviouse mis-repesentation of the product!

The next day I got a call from the husband who was now under the impression that the whole system was a failure and that it all  had to be redone — Why was the coating so soft ?

On close inspection he did apply the material correctly and didn’t over load the materials on the surface, he used a water based grain filler and so was OK there (  had he used a solvent based grain filler and had not let that fully fully dry, like 48 hours or more that  would have caused problems). So what was going on here?

The answer?  nothing was wrong! the materials just needed a longer cure time. Mrs Enthusiastic scrubbed the glue a mere 48 hours after it had been applied.

409 shouldn’t be used on your new cabinets in the first place even when they are fully cured.

The point here is that you have to let the water based lacquers fully cure.  and full cure comes after 30 days! not that they are not hard enough to install in a few days but if you think that you are going to have immediate abuse then you should hold the parts a few days longer before installing them.

After 4 days of curing the finish was twice as hard. it still loosen up a little and lost some finish with vigorous scrubbing and 409 but it was twice as hard.

On a close study of the KCMA ( Kitchen Cabinet Manufactures Association) tests that the materials passed.  they make the point in  the tiny fine print that the doors tested had been let allowed to cure for 30 days befor they were subjected to the chemical testing.

When you think about it, the water-based materials have to be allowed to air dry. There are no other solvents other than water. The other thing you have to think with is the fact that the materials are going to dry from the top down, I.e they are going to dry on the surface with the deeper and deeper layers drying last.

I have found that once you have let the stuff fully cure it it actually far tougher and far more chemically resistant than their solvent base counterparts.  Ya, just have to let them dry !  

I have promised the homeowner that I would return in 30 days and would test again the hardness of the materials at which point We’ll have full dry and one heck of a finish.

There are two lessons here:

  1. You have to figure in to your equation letting the materials fully cure. That doesn’t mean that you can’t install them until then but if your do install the cabinets you need to know that you have to be gental with the finish for a month or so.
  2. Have the right equipment and read all the printed materials about the materials you are going to be using so that you know what you should expect.

I’ll post the pictures when I get the from the homeowner after the first of the year.

The water based lacquer by the way was Gemini’s titanium white with the white sanding sealer under that

Greg Saunders
Reseda, California

November 20, 2008 Posted by | CIC Centurion, water based Conversion Varnish, Finishing failures and the fix, Tips and Tricks, Water based Lacquers, Wood finishing | , , , | Leave a comment