Conversion Varnish on Marble Table Tops

How to make wood finishes stick to stone. August 16, 2012

This is a new one by me. I was given a bid proposal from a stone company to seal/topcoat 30" white marble cafe table tops. They are to be used in a bar setting and have been spec'd to be coated with 2 to 3 coats of MLC Krystal Satin.

I have recently switched over to Valspar (and am loving it) as my drug of choice, but can easily get MLC product for this one off. Stone company owner states that this type of work has been done before with Krystal, but the original shop he used is belly up. Sign of the times, bums me out...

Any input is appreciated. I get that the porosity of the marble will help the Krystal to initially stick/sink in, but how the hell will it stay on the surface for more than 2 months without cracking/peeling/flaking?

Forum Responses
(Finishing Forum)
From contributor L:
The acid catalyst might bite into the stone.

From contributor C:
You'll need a tie coat, an isolation sealer meant for good adhesion to the surface of the marble. I prefer XIM 400 clear which I have used with great success on marble, glass, and other hard to adhere to surfaces.

The trick is to make sure the surface is chemically clean - not even oils from your hands. I use alcohol for this mainly - several wipes with clean, fresh paper towels.

Next, apply the xim. Just one light wet coat only, not thick. Allow to dry overnight, then without sanding, apply your overcoats of finish. Again the first coat should be a mist coat, followed by a very light wet coat and then a normal coat.

I have not used Krystal or other conversion finishes with the xim, so do samples and test to be sure of the results and adhesion. Most of my work was with either nitrocellulose or acrylic.

From contributor T:
Thanks for the info. I had already figured on the clean surface prep before anything is applied. There are 12 tables to be shot. Since I will only lay down a mist coat to start, I think 2 quarts would be enough. According to the XIM site you can order direct, but I bet the shipping/Hazmat charge is steep.

You mentioned you had not used Kry as a topcoat over the XIM. What did you use? I cannot imagine in my wildest dreams a nitro would last long as a topcoat for durability. What type of acrylic did you use? As I mentioned, these tops are white, so a non-amber topcoat will be in order.

From contributor T:
MLC offers a products called Klearplast, which is non-yellowing and can even be sprayed over metals. Don't know if this type of product might help.