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.
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.
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.
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.
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.