Minwax Polyurethane

[Beeg]

I made the mistake of being lazy and not testing before applying to a project. Petroleum based Minwax Polyurethane will yellow in about two days. I used the gloss spray which goes on very nice and smooth hoping for a nice gloss finish for crisp mask lines. It is smooth and masks very well but on a white surface the yellowing is very noticeable.

In the pictures below you can see the white on the main wing which I clear coated before wanting to apply the blue has yellowed. Compare it to the white on the stab which isn't clear coated and the piece of paper. Bummer, have to repaint the white.
I have not seen this kind of yellowing with water based Minwax Polycrylic.

Here's the evidence so don't make the same mistake.

[CT]

Solvent based coatings are notorious for yellowing white or light colored foam. I have used spar varnish on my black colored rebel and is tough as nails and a bulletproof coating, but now have given up on applying poly and instead use Oracal which provides a much smoother overall finish, and provides great structural stiffness to the components.

[weedsnager]

This is what you want to use

[Beeg]

This is what you want to use

Yes, that is what I usually use. I just wanted to try a petroleum based product. Should have just stuck with what works.