Best resin for handling temporary high temps

Hi
I make earrings using paper images that I then build frames around using soft solder (soldering iron). I have been using a simple water-soluble sealant to protect the images but the heat from the iron’s proximity buckles and causes bubbles in the sealant layer. It’s “ok” because it works with the ancient look but it’s not completely what I want and I would prefer a more durable sealant. I am thinking “resin”

So what I would need is a resin that can be poured onto miniature detailed paper images (clear!) that will cure not tacky on surface — surface depth approx 1mm — and that will be the LEAST likely to be burned or whatever from the heat of the edges being in proximity to hot solder.

I know this is a crapshoot at best but willing to do a small test to see if it’s an improvement over the water based sealer effect.

Thanks!