We are re-coating a section of oak bar about 7 ft long between two drink dispensers with a two-part epoxy pour on coating. This had been coated with the same thing 20 years ago.
FIRST COAT Temp approx 65-70
We hand sanded, wiped with acetone, mixed it thoroughly by hand as instruction, poured it on and squeegeed it out with wide knives.
Close to each end – which would be close to where drinks (soft drinks and alcoholic) were dispensed we had a cratering problem. We would level those out and it would return. Let me emphasize this is not bubbling – there is no gas coming up. It’s as if the epoxy in the middle of the crater is GONE and it seems there is a little rim around the edge of the crater.
SECOND COAT Temp approx 65-70
We thought we had misread it and it wasn’t sealed in those areas. So today we sanded, wiped with acetone, and re-coated. Same thing. We called the company in Calif for tech support with no clear answer. We tried filling the craters while still wet and they returned. They recommended very light “torching” with an lp torch which we tried with no noticeable result.
I hope somebody on here knows what’s going on and give us a clue on this. I also called the guy who originally coated the bar and he hadn’t had any problem like this. These pictures were taken during the second coat after efforts to fill the craters.
Replies
Had someone at one time siliconed in the joint on the left? Perhaps that's some slop from b/4 and it's causing it.
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Thanks, your post and the next one got me thinking about what's happening and I think you're right. I plan to do a test on another piece of wood today with some silicone drops on it. So as I understand it the silicon contamination is so slick that the surface tension of the epoxy trying to level out is greater where there is no silicone than where there is, so the leveling tension pulls the epoxy away from the slick spots. The thing that is vexing me about this is that I have heard that silicone penetrates DEEP and I'm not optimistic about being able to remove the silicone. Even if I had this down to bare wood it would be iffy and with at least 3 coats of epoxy pour on we're far from bare wood. I don't have confidence that I can rub a special thinner around in those craters and remove the silicone - but I would hope I'm wrong. Do any of you have any thoughts on how to overcome this? (I have heard about this problem on autobody - a guy told me you had to take it down to bare metal to get the silicone off)
What you describe sounds like silicone contamination. Could come from WD40 having been sprayed in the area, or a wiping rag contaminated with silicone or "dry" lubricant spray. Quite possibly the drink vending equipment was sprayed with silicone lubricant during routine maintenance. Acetone won't remove it but vinegar might. Also xylene may get it.
From WoodWeb http://www.woodweb.com/knowledge_base/Refinishing_contamination_problem.html
"SW makes a solvent specifically formulated to be used prior to refinishing. It will remove silicone. R7K156 "
"Just wash the furniture with mineral spirits and wipe with paper towel. Do this a few times. Mineral spirits do not neutralize silicone - they disolve it and must be removed with paper towels. If anyone ever sprays WD-40 in your shop, they must be banned forever. One small squirt of WD-40 can give you years of fisheye games. It is a good practice to alway wash with mineral spirits after stripping. It will also remove the wax left by the stripper. "
Good luck
Thanks and I didn't know there was silicone in WD 40. I think your post and the other one have identified the problem. I'm baffled about solving it. There is surely a way to neutralize this?
There isn't silcone in WD-40, it doesn't contaminate that way.
The common cure for "fish-eye" which is what you have, is to add silicone to the coating. It is called fish eye eliminater and sold as such. It will contaminate spray equip. and I have a gun that I use for refinishing type refinishing and one for new work.
A few drops in the new epoxy ought to fix it.
BTW, if you sanded with whiteish stearated sandpaper that too can cause what you see..stearates are like a soap and react with some finish..
It is said that a drrop of silicone the size of a pin head, can migrate and contaminate an entie VW bug with fish eye.
Relevel it, use black unstearated paper, buy fish eye eliminater, and recoat.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
Sphere,Thanks for the tip. We ask what is used on the top today (pledge and murphy's) and did a test. We got the same cratering with pledge, murphy's, silicone spray. The wd 40 didn't react.I'm including pictures. My wife looked up and pledge has silicone oil in it. So there's no way to remove the silicone from the wood right? Just add it to the finish.
Yep, Pledge is the culprit. You could seal the top with Sealcoat by Zinnser, I've pulled that off in the past. I dunno about adhesion isssues tho' with the epox.
The Fish eye eliminator is probably your best bet, mix it really well, it don't take much.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
Sounds like fisheye. Did you use sterated sandpaper to sand surface? They contain lubricants that can affect the adhesion of some finishes.
The time you'll spend fighting this might be better spent covering it....
An idea or two might be to take a flat bottom router bit and route away the finish and some of the contaminated wood to a depth of the thickness of what you will use. Try to find some type of pre-made inlay veneer pattern, a trim of matching face cards from a new pack of playing cards, or unsealed ceramic tile inlayed and that tends to relate to the theme and/or colors of where the counter is.
You are at a point where the depth of the clear coats can really take a good sanding to smooth and level the dried coats. Vacuum and Wipe away all the dust. Then, recoat the counter top with another coat of the clear epoxy.
Bill
You said you sanded first then used a solvent to clean ... try it the other way around. Solvent clean then sand. Sanding dirty surfaces only pushes the contamination further into the substrate.