One of the most asked about and experimented with in the alcohol ink communities is all about sealing tiles and YUPO paper.
Step 1:
 Krylon Kamar for the first coat. I like that it because it does not disturb my signature or the painting.  I usually do two coats. (Even if you decide to try resin use this spray first.)

Step 2:
After Kamar varnish, I now use Rust-Oleum often found at a hardware or automotive store.

Step 3:
Alcohol inks will fade in direct sunlight. I tell customers not to have the tiles displayed in direct sunlight so I usually skip this step. However many artists do include this step to help protect against fading caused by harmful UV light rays. It is also moisture resistant and smudge-proof. link to UV Spray

Another Option:
Art Resin
https://www.artresin.com/
To protect artwork from heat many artists are swearing by using Art 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. Here are a few links to some YouTube videos on how to use Art Resin. Â (Even if you decide to try resin use one or two coats of Krylon Kamar spray first.)
Video to use on tiles. https://youtu.be/i0JBSxDIUsUL
