How you know when you plaster is too old!

Question

Having listened to the various tales of woe regarding using old plaster, I wondered how old is "too old"?

Having just purchased seven bags of multi-finish and humped them up two flights of stairs, I popped out to the workshop to collect the plastering tools. Happened to notice that there was still a 1/3rd of a bag remaining that I had opened a few weeks prior. Thought, its not been there that long, should still be OK, might as well use that first.

Mixed to a nice creamy texture, I deposited it on a spot board and went to wash out the bucket... came back five minutes later to find a solid mound of plaster glued to the spot board! Guess that answers that question!

Mark S. · Accepted Answer

It's funny that isn't it. ;-)I did it once, mixed half a bucket and it went off by the time I'dcarried it upstairs. :-)Mark S.

Andrew Gabriel · Answer

Well, you did answer your question. There's normally a "use by" date on the side of the bag, and sometimes it's even readable ;-) I've used bonding coat up to a year after its "use by" date, but it had been stored in a warm dry location. I wouldn't use finish coat plaster after its "use by" date, as if it goes off too quickly after you get it on the wall, you're screwed. However, an out-of-date bag is useful for small patching jobs where you want it to go off quickly.

John Rumm · Answer

Yup - March next year it says!It was in a cool dry place - open for perhaps 4 to 6 weeks.Good idea.... unless it is sitting in a lump fixed to a bit of board! Still the other new bags seem fine.

How you know when you plaster is too old!

Join the Discussion

Didn't find your answer?