Bar Top Finishes
Here's some practical info on using two-component polyurethane or epoxy bar-top finishes. April 10, 2008
Question
I am building bar tops for the service bar and also a bunch of the table tops for a commercial coffee bar/deli. Against my advice, the client wants all these table and bar tops to be constructed from 3/4" oak plywood with a solid oak edging. These will be subjected to the usual washings between customers and coffee spills, etc. What type of finish would be the norm for this type of application? If it makes any difference, they will be stained as well. I currently use a Binks pressure pot and 2000 spray gun to apply mostly lacquer finishes.
Forum Responses
(Finishing Forum)
From contributor D:
Lacquer will not do on these surface. I would consider, at the least, conversion varnish or 2k poly. I would also consider what glue you will be using to attach the edging to the plywood tops. There are other finishes which would be suitable for these surfaces; some can even be brushed and poured.
From contributor C:
Ditto on the 2 pk polyurethane.
From the original questioner:
One of you said "2 K" and the other "2PK." What does this mean? Can I spray this finish with the above equipment? I need a finish that will be correct and hopefully not too difficult to apply.
From contributor C:
Same product; both mean a two component urethane. One can is the acrylic polyol, the other can polyisocyanate/polyurethane. Make sure you clean your equipment up well, then you can use in your pot. No easier or more difficult to use than, say, cat varnish or other cat finishes. But make sure you get and read all the info from the supplier so you know the ins and outs of that particular product. Sands and buffs well to a high polish. You may have to get a larger fluid tip and needle assembly and possibly an air cap change also, but you may have to do that with any higher solids coating you deem to use.
From contributor A:
Did the same job 3 years ago. Used conversion varnish and it did well, until they started using an ammonia-based cleaner. Now I need to go rub some acetone on it to re-dry the finish on the tables. But the bar (they polish with Pledge every day) has done wonderful. I'd look at a poured finish.
From the original questioner:
Can you recommend any names on poured finishes? Sounds expensive, but worth looking into.
From contributor C:
glueproductsplus.com carries epoxy table top finishes. Almost everyone in south Florida uses their pour products. I don't remember the name, but they will be of great help - ask for Charlie.
I was looking at your initial post again and wondering about the specs. 3/4" ply with solid molding? Is the molding also to be 3/4", so that it looks like a solid 3/4" top? Or is it to be wider to give the appearance of a thicker top? If pouring or building a thick coating on something that thin, remember to pour both sides, or it may give a warped appearance. Just a caution - happened to me once when I first tried pouring over thin top material. I had to flip them all and pour the bottom side to even out the contraction caused by the shrinkage of the top side. Was not bad - but enough that it did not look glass flat.
From the original questioner:
Your thorough help is much appreciated. The tops are constructed with 3/4" thick oak plywood and edged with 3/4" x 3" solid oak lumber. In other words, the tops appear to have an apron or seem to be 3" thick on the edge. Anybody else have warp problems with one side pour finishes? How will the 3" vertical edges be finished in this case?
From contributor C:
If by chance you do have the warp problem, only the flat underside would need to be poured as thick as the top pour. The edges coated with the top pour will be sufficient with a hang coat from the bottom pour on the underside. In other words, you don't have to fill the whole cavity on the underside, just put close to the same amount as the top. Again, this is only if you experience any bowing from contraction; you may not.
From the original questioner:
Rest assured I will not pour a 2 3/4" thick bottom coat on 20" x 30" tables! I am curious how the pour-on finishes work on vertical surfaces such as my table and bar top edges? What is the procedure?
From contributor C:
The process itself is not complicated, but there are many factors to consider. First, you have to have an area which is dust free - a clean room - then you must set up tables smaller than your tops to put your tops on, and they must be as level as possible. Mix the components together and slowly stir, not causing any bubbles to be formed. After the required mixing, I started my pours in the middle of the table. (Note: you'll have to do small pours on a small surface first to determine how much you'll need to mix per table to acquire a 1/8" or 1/4" thickness.) Starting in the middle, I apply enough to ensure it will run over the edges all the way around. At times I have to help it along - the coating on the edge will be thinner than that of the top, but this is fine - no need to worry about the edge having the same mil thickness. The coating is heavy enough to totally build up over the pore structure and smooth out nicely. After that, it's just a matter of letting it cure. Also instructions for the product will be available for other anomalies such as bubble formation and its cure.
From the original questioner:
Thanks. Now the main question in my mind is the cost of such a finish. Is this the most common finish for a commercial wooden bar top? I am just not sure there is enough money involved in this project and the dust factor scares me. It is so cold right now that the dust will have plenty of time to find the finish before it hardens.
From contributor C:
It's not cheap - but your best bet is to call for present pricing, as I have not poured any since 1998.
As to the cold and dust, if you cannot set up a clean room, I would advise against its use. I don't think you'd be happy with the end results. Maybe our first thoughts are best as to a 2 component urethane, but here again, if you're saying your shop is cold (below 70 degrees), this might not be viable either, depending on the product. So if you go that route - 2pk - make sure it can be sprayed at the temperatures you're experiencing. Remember that whatever you use, the air temp, item surface temp, and material temp all have to be and stay above the minimum requirements stated by the manufacturer! If this cannot be accomplished, I would not take the job on until you can do it without worries like these.
The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).
Comment from contributor A:
I've used these two part resin finishes before and it is almost impossible to mix them and pour without getting bubbles into the mixture. Many will rise to the top themselves and dissipate. The others will have to be coaxed out by using a hair dryer to blow cool air across the top of the drying surface. The bubbles will magically rise to the surface where they can escape. It takes a while but keep at it.
