Why nobody warns you about mixing wet mud brands on the same job

Used to grab whatever joint compound was cheapest until last month when I mixed USG and ProForm on a ceiling in Phoenix and ended up peeling tape off 4 sheets after it wouldn't cure right - has anyone else had that screwup or just me?

2 comments

2 Comments

adam_thompson5316d ago

Melted a 5-gallon bucket of USG by accident one time when I left it in the truck on a 95-degree day and it turned into watery soup. Tried to save it by mixing in some DAP from a half-full bag and ended up with this weird crumbly paste that dried like old playdough. Actually had to chisel that mess off a whole closet ceiling with a putty knife and a lot of bad language. Idk what it is about mixing brands but it's like trying to combine Coke and Pepsi in the same glass - you just end up with a sad drink nobody wants.

clark.robin16d ago

Funny you bring up the Coke and Pepsi thing, but I actually think that proves my point - people who swear they can tell the difference in a blind taste test usually can't, and the same goes for mud. I've been mixing whatever leftover buckets I have for years (USG, ProForm, Sheetrock, even some no-name stuff from a hardware liquidation sale) and never had a single fail like you're describing. The chemistry of joint compound is basically the same across brands - limestone, latex, and a few thickeners - so unless you're mixing a fast-set with a drying type, which is a whole different problem, I think the real issue here is probably more about bad technique or maybe a contaminated batch. People love to blame the materials when their tape bubbles or their mud cracks, but more often than not it's something like an unprimed surface, wrong water ratio, or just working in Phoenix heat without a wet edge. So I'll be the guy saying "go ahead, mix your brands" - it's not a magic potion that's gonna blow up in your face, it's literally just plaster.

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