Craft finishing

[wrmnfzy]

My wife and I do some craft fairs. I do the woodworking and she does the painting. She uses acrylic craft paints and then finishes with craft urethane matte varnish. We have noticed that when temperatures get very hot the varnish appears to turn a yellow tint most noticeable on the white painted crafts. Any ideas how to stop this. I have never been much of a finisher.

[ERLover]

Not know what type of Varnish, oil or water based, Shellac?
Oil based Polys/Varnishes do add a yellow tint no matter what the temp. Water based Poly is the clearest of any finish, it will not add yellow.
Shellac comes in different tints and can add a lot of toning and if applied in humid weather, can dry cloudy.

[wrmnfzy]

It says it is a polyurethane varnish that is non-yellowing.

[ERLover]

It says it is a polyurethane varnish that is non-yellowing.

Water base or oil? Which brand?

[wrmnfzy]

Water based. I've attached a picture of bottle.

[ERLover]

I dont have an answer, other then try a different brand of water base poly and try it on a sample piece. I have used MinWax and did not have much yellowing, but it was not over white.

[Gene Howe]

I have never seen or used any poly, oil or water based, that was truly non yellowing.
You might try spray lacquer. Or, if you are satisfied with the durability of the paint, wax does great.

[wrmnfzy]

I might try another brand if wife goes along, she resists change. Can't use was many small raised parts and letters that would make it hard to get between.

[wrmnfzy]

Oops, forgot the most important part, thanks for thoughts.

[Gene Howe]

The brand will likely make little difference. Try a can of lacquer instead of poly. I use the Ace brand. Cheap and effective.