One of the most asked and experimented with in the alcohol ink communities is all about sealing tiles and YUPO paper.
1. Many artists swear by Krylon Kamar for at least a first coat. I now do this also. I like that it does not disturb my signature or the painting. I usually do two coats.
2. Next, I use Krylon Triple Thick Crystal Glaze. I may use several coats. Spray lightly from about 12 inches away. Let each coat dry thoroughly before adding another coat. Once I seal the tiles I let the art cure for about a week before letting anything touch it.
After at least one coat of Kamar instead of Krylon Crystal Clear Triple Thick spray an inexpensive alternative is Rust-Oleum often found at a hardware or automotive store.
To protect against fading in sunlight use.Provides a permanent, protective gloss coating which protects art, crafts, and valuables against fading caused by harmful UV light rays. Moisture resistant and smudge-proof. link to UV Spray
To protect artwork from heat many artists are swearing by using resin. This one is very popular and I just got some. It does look simple to use. They have great videos on how to use it. I just got mine and look forward to trying it out.
Link to buy Art Resin