Dealing with Silicone Damage
A refinisher asks how to get silicone off a conference table he's refinishing, and gets a handful of ideas. June 28, 2005
Question
I am refinishing a conference table, and I've been having a difficult time with silicon damage. I have tried silicon washes, washing down with ammonia (which usually works for me), and spraying light barrier coats of vinyl sealer. Are there any other tricks or products that anybody may know of that might work?
Forum Responses
From contributor D:
I would suggest that you ask your distributor for a bottle of fish eye killer or similar product that breaks the surface tension and allows the finish to flow smoothly.
From contributor S:
Rather than vinyl sealer, which can float the silicone oils to their surface instead of forming a film barrier over the oils, spray on shellac. Zinsser seal-coat is premixed and thin, and ready to spray. It is a dewaxed pale shellac.
The idea of a barrier coat is to keep those contaminants underneath them. Any coating can do this (usually) if the coating material dries quickly after landing on the surface, quickly enough that the silicone oils do not become part of the coating. That way, the silicone oils stay underneath the dusted coating, and you will have something to scuff.
Shellac works because the solvent for shellac is alcohol and the shellac has great adhesion properties. The bad oils tend not to mix into the shellac spray, but you still must apply light coats. Spray on a couple of light coats. Barely scuff the second coat to create a tooth and continue your finishing from there.
If the surface needing cleaning is a conversion varnish, use xylene as your solvent wipe. It has more solvent strength than naptha and mineral spirits. The problems with xylene are the toxic nature of this chemical. And even though your xylene rag will dry out it will still stink. The xylene stench is a stubborn one. Wear gloves when using xylene.
You can also add fish eye eliminator to your coating if you are using lacquer, pre-catalyzed lacquer, or catalyzed lacquer. As a prepping wash, TSP and water will have an effect on the presence of silicone oils, and it may likely soften the finish as well, so this is not always the best on-site problem solver.
From contributor T:
I tried fisheye removers and additives and they didn't work everytime. What does work for me is misting the finish on. After I spray the first coat, I look for any fish eyes, and if any appear I simply go back and mist the surface from further away with a low material flow out. The thin coats seal the fish-eyes. Lightly sand when dried, and with the next coats you're back to a leveled surface.
From contributor M:
To Contributor T. I use that same misting and fogging technique over all of my stains, glazes, toners, shading stains, opaque colored coatings, gold and silver leafing, etc. That also includes my sealers and clear coats.
From contributor P:
To contributor M: Why do you use that misting technique over all those finishes?
From contributor M:
To contributor P: I found that by misting over all the finishes first, I set the stains, glazes, etc. with the misting, and this prepares them for the coming flow coats of sealer or clear coats. I can use this misting technique as soon as I complete my glazing, no waiting for the open window. If there is contamination, the misting in most cases will not bring it out, but will seal it in.
From contributor B:
We used to use the misting method before we had the silicone additives. If you have a lot of time its fine, but you can only fight silicone with silicone. And of course, take it easy on the mileage on the first several coats. Also, taper off the silicone additive as you apply more build coats and ect.
From contributor M:
The big problem with silicone additives is that once you add it, you need to add it to every coat. Reducing the amount helps, but you will need some in every coat. There are times when you have to either add the silicone additive, or strip the piece. Refinishers live with this problem on every piece they work on.
From contributor B:
I would rather add some additive thin strip the pieces. Plus, if you strip it, the silicone is still there and always will be. One trick I use to cut way back on the silicone additive is to reduce it in a thinner. Sometimes its just a drop of additive in a gallon of reducer and the problem is solved.
Plus, many coating formulations have some silicone in the formulation already.
