Totally agree about the epoxy discoloration—seen it happen a bunch of times myself. Another thing worth mentioning is temperature swings. Epoxy repairs on porcelain can sometimes crack again if the sink regularly switches from hot to cold water. As for fiberglass mesh patches, they're okay-ish on fiberglass fixtures, but on porcelain they usually don't bond well enough long-term... better off biting the bullet and going pro if it's a high-traffic area.
Good points about temperature swings, hadn't really thought about that before. Makes sense though, porcelain expands and contracts differently than epoxy. Wonder if anyone's tried using a flexible sealant or something similar underneath the epoxy to help absorb those temperature changes... might give it a bit more durability? Curious if that'd even work or just create more issues down the line.
"Wonder if anyone's tried using a flexible sealant or something similar underneath the epoxy to help absorb those temperature changes..."
I've actually experimented with something similar on a porcelain sink repair last year. Used a thin layer of silicone sealant under the epoxy to give it some flex. It held up pretty well initially, but after about 6 months, I noticed some slight lifting around the edges—probably due to moisture getting between layers. Might work better if you can ensure a perfect seal, but honestly, long-term durability might still be questionable...
I've actually experimented with something similar on a porcelain sink repair last year.
Tried something similar myself, but silicone under epoxy is tricky. Silicone tends to repel adhesives, so even a tiny gap can let moisture creep in. If you're set on DIY, maybe try a flexible epoxy instead—might hold up better long-term.
Yeah, silicone under epoxy is a pain. I learned that the hard way when I tried patching up my mom's bathroom sink last summer—thought I'd nailed it until she called me two weeks later saying it was leaking again. Turns out water had snuck right under the epoxy through a tiny gap. Ended up redoing it with a flexible epoxy, and it's held up pretty well since then. Lesson learned: silicone and adhesives are frenemies at best...
