I'm making my own small resin jewelry pieces, using metal for framing them. I'm using Mercola liquid glass crystal resin that is advertised as being extra strong and ultra transparent. I mixed it at a ratio of 100:55, and sometimes months after curing, I see the jewelry starting to get foggy even though I'm protecting them from substances like perfume.
I need the resin to stay clear and not to get cloudy over time. Is there any solution for this? Maybe a varnish that keeps it clear?
A change after some time means there's something unreacted in there.
The instructions say 100:50, and imply that's by weight. Are you weighing precisely? An imbalance is likely to leave unreacted material. A set of 0.1g kitchen scales can be had for £/$/€10-20. But why are you using 100:55?
Are you mixing small quantities, thoroughly but by hand? It sounds like it's quite quick-curing, but you need thorough mixing to ensure it reacts properly.
Finally the instructions say to ensure absolute dryness and even low humidity. Bringing the epoxy from somewhere cold into a humid workspace would be particularly bad. Again, water in epoxy can cause cloudiness, but that's more likely to be immediate. If you're using dyes, make sure they're the proper ones, and not introducing water. Even alcohol-based products can draw water out of the air if left open.
I agree with Chris H. that it's probably inaccurate mixing. Imagine 2-part epoxy like one liquid with chemical locks dissolved in it and another liquid with chemical keys in it. It only hardens if one lock reacts with one key, so for a perfect result you want the perfect number of locks and keys in your mix. If you have to many locks and too few keys in the mix (or vice versa), some part of the epoxy will remain liquid, even though the object feels hard and sturdy.
So please try to mix both parts of the epoxy as closely as possible to the manufacturers instructions. Read the instructions carefully to determine whether you should measure the parts by weight or by volume, that can make a difference.
When mixing the parts together, make sure you scrape the sides and bottom of your mixing cup. Personally I find scraping the sides and bottom more important than mixing the center of the cup, because the center gets mixed automatically by that. Not mixing epoxy properly is just as bad as using a wrong ratio of the parts - you have the correct number of locks and keys in your mixture, but if they never touch they cannot harden properly.
Some resins change color while mixing, some are clear from the beginning. It's harder to see in clear epoxies, but if you look closely, you should be able to see that the resin looks foggy when you start mixing it. It's not opaque or even whitish, it looks maybe like a wisp of steam where the 2 parts touch. Once the resin is mixed properly this fog disappears completely.
One last note: Please avoid breathing in the fumes of the epoxy when looking at it, they can can irritate and damage your airways, even if the epoxy doesn't stink. You should only mix and cure epoxy in a well ventilated room or outside.
