I've seen this happen quite a bit actually, and you're onto something with the temperature swings. Porcelain can be tricky because it expands and contracts more than you'd think, especially in colder bathrooms. Honestly, epoxy kits vary wildly in quality—some hold up surprisingly well, others just don't seem built for long-term fixes.
Have you considered the thickness of your application? Sometimes, thinner coats flex better with temperature changes, while thicker layers might crack easier. I've also noticed that prepping the surface thoroughly makes a huge difference, but even then, porcelain tends to be stubborn.
Material compatibility definitely matters. In my experience, certain brands just bond better to porcelain sinks specifically—it might be worth checking if there's an epoxy formulated explicitly for ceramic or porcelain fixtures. But yeah...sometimes these DIY fixes are just temporary band-aids. If the cracks keep coming back, it could be time to bite the bullet and get a pro involved.
"Have you considered the thickness of your application? Sometimes, thinner coats flex better with temperature changes, while thicker layers might crack easier."
That's a good point about thickness. I've found that applying multiple thin layers, allowing each to fully cure before adding the next, tends to hold up better over time. It takes patience, but it can make a noticeable difference in durability.
Also, surface prep really can't be overstated. I once rushed through sanding and cleaning a porcelain sink before applying epoxy, and sure enough, the cracks reappeared within a few months. The next time around, I took extra care—used fine-grit sandpaper, cleaned thoroughly with rubbing alcohol, and let it dry completely. That repair lasted significantly longer.
Still, I agree that DIY epoxy fixes often end up being temporary solutions. If you're seeing recurring cracks despite careful prep and application, it might be worth considering a professional refinishing service. They typically use specialized coatings and equipment that can handle temperature fluctuations better than standard DIY kits.
Good call on the surface prep—it's amazing how much difference that makes. Still, I'm a bit skeptical about DIY kits long-term.
"DIY epoxy fixes often end up being temporary solutions."
Exactly my experience too. Sometimes it's better to bite the bullet with a pro job...
Had a similar issue with a cracked porcelain sink in one of our rental units. Went the DIY epoxy route first, thinking it'd save some cash. Looked great initially, but within a few months, the crack reappeared and actually got worse. Ended up calling in a pro who explained that DIY kits rarely penetrate deep enough to stabilize the crack properly. He redid the job, and it's held up perfectly ever since—almost two years now. DIY kits can be decent for minor cosmetic stuff, but for structural cracks or anything that sees daily use like a sink, I'd lean toward a professional fix. Saves headaches down the road...
Yeah, been down that road myself—DIY epoxy kits can be pretty hit-or-miss. Had a hairline crack in our bathroom sink, thought I'd nailed it with a DIY fix, but nope... couple months later, same story as yours. Ended up biting the bullet and getting a pro in. Cost more upfront, sure, but it's been solid ever since. Lesson learned: sometimes saving money means spending a bit more at first to avoid headaches later. Glad yours worked out in the end!
