Conversion Varnish Glaze

Advice on applying CV glazes. February 29, 2012

I just picked up some Van Dyke brown for use on my first glazed conversion varnish finish for an island. Up until now I've always used Mohawk aerosol glazes under pre-cats because it was easier and the pieces didn't require conversion varnish.

I’m working on a pigmented finish (primer, 2x pigmented cv, glaze, cv top coat), and the glaze seems to be thicker and dry faster than the Mohawk glaze. What is the most popular or easiest way to apply/remove this product? I usually work with a rag and soft brush but the results aren't the same with this stuff.

Also, I always sand with 280-320 between every coat of sealer and conversion varnish - what is the proper prep work before the glaze step? I don't sand when using pre-cat because even with a fine scuff pad it tends to show the pattern, and I'm concerned about getting the proper bond between the layers of conversion varnish. I've always been very happy with Sherwin Williams products.

Forum Responses
(Finishing Forum)
From contributor M:
You're right, you don't have to sand your pre-cat when glazing because that finish burns into the last coat even if you have used a wipe-off glaze between coats, and you wipe off the excess glaze well. You're also right that this is not the case with conversion varnish. It does not burn into the last coat of finish, so you have to scuff up that last coat either before or after glazing.

To solve the thick-glaze problem I thin it with paint thinner which is slow drying. If I want a heavy-glazed effect, I scuff the prior coat of finish before glazing. If I want a light-glazed effect, I scuff after glazing.

If I want just glazing on edges or recesses only (crevice glazing), I do not use regular glaze, but just mix pigment with acetone and spray it where I want it with a narrow-pattern gun without scuffing the prior coat. Scuff after this glaze and you will have glazing just in the crevices and edges. The scuffing removes the excess glaze and prepares the surface for your final clear coat as well.

From contributor W:
S-W has two types of glaze - Sher-Wood Glaze and Sher-Wood KemVar Glaze. The KemVar glaze will give you good adhesion without sanding, and is suggested for use with their catalyzed systems, like conversion varnish. If you have the standard Sher-Wood Glaze, most use fine grit paper (320 grit) or Scotch Brite pads (maroon #7447 from 3M). Keep in mind that if the glaze has dried for more than four hours, then too fine of a grit may not be sufficient.

As far as reduction, both of the glazes may need reduction or retarding for more “open time” on some applications. You should use aliphatic naphtha. Your supplier should have Mineral Spirits (medium) or 140 Flash Aliphatic Naphtha - R1K140 (slow). These can be used in any proportion depending on the desired open time or rate of evaporation. Once the glaze is reduced, you should be able to resume your normal technique with a rag or brush. Keep in mind that the glaze will re-wet as well. Another application to the glazed surface will wet the existing glaze so it becomes workable again, just be sure to wipe all excess from your board to avoid adhesion problems.

Pay close attention and note that film thickness of the finish and/or glaze, shop conditions and time allowed between each step can impact your results. The difference is that the Mowhawk aerosol glaze must be pre-reduced in order to be filled into a low-pressure aerosol can versus getting S-W concentrates and reducing to your liking. S-W can have glazes filled through their finish repair program. Any of their Product Finishes facilities will be aware of this program. This package would be more comparable to the Mowhawk product.