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