PU is also used in the automotive industry. Metal shrinks/expands more under temperature changes than our glasfiber wings do. Is it too easy to say that if polyurethane works on cars than it certainly works on gliders?

I don't intent to do the paintjob myself, but I'll go to a professional EASA approved workshop, and they use T35 as groundlayer. Would that affect the crack resistance (against temp changes) in a negative way?