Alternatives to conversion varnish

Is there a less-touchy alternative to conversion varnish? January 24, 2001

Q.
I make architectural woodworking products and use Sherwin Williams WW conversion varnish, which Iím not getting consistent results with. I chose conversion varnish for durability, but am wondering if thereís a better product out there.

Forum Responses
With conversion varnishes, you must maintain a very stable temperature and humidity. Catalyzed lacquers are less picky when it comes to swings in temperature and humidity. They also flash quicker.



The water-white qualities of conversion varnish give the wood a very "dull" look and not the warm amber cast most catalyzed lacquers give. The conversion varnish is used where you want extreme durability without the amber color, over light-colored stains or as a clear over a pigmented product.


Is there a way to tint conversion varnish to get a little of the amber color?


You have to check with the tech support from the manufacturer of your particular conversion varnish, to find out if you can tint it.

In general, add a small amount of dye (not aniline). Transtints are concentrated dyes that can be added to a variety of vehicles and coatings, conversion varnishes included. Some dye types may color-shift when added to catalyzed coatings. Transtints should not do this. In general, metalized dyes shouldn't do this. To insure no funny reactions, test.



Iíve switched from conversion varnish to ICA polyurethane and would not go back to anything else.



I prefer urethanes because my eyes burn when I spray varnish, and the smell lingers.
Bob Niemeyer, forum technical advisor


Conversion will tint with lac. dye stains and MEK based dye. It will also tint very well with 844 colorants (most good paint stores use this UTC-type colorant for epoxy).

My problem with shading/toning with conversion varnish is the inherent slow dry time and poor sanding quality. I have used a vinyl or non-sterite to seal, shade/tone and clear coat, then conversion varnish. You lose some durability from possible delaminating, but get better color.



I decide what finish to use on a job based on whether or not it has to be installed in the field (base and crown moldings, chair rail wall paneling). If these will be field cut and nailed, there will be extensive touch-up or a full-on re-spraying.

Conversion varnish is a definite no-no in the field. In these situations I have found a pre-cat lacquer that will re-wet with lacquer touch-up sprays for field touch-up. For free-standing furniture or casework, conversion varnish is fine.