DIYbanter - View Single Post

In article .com, wrote:
[snip]
My problem is that the
original bag of unused grout seems to have gone bad. Does unused grout
go bad? [...] Also I can't
believe grout has an experation date but I guess it does. This stuff
has begun to clump and I have to sift it before mixing to get the lumps
out.

Yes, it does go bad. Grout cures because it undergoes a chemical reaction with
the water that you mix into the powder. (The same is true of plaster of Paris,
mortar, cement, plaster, etc.) It undergoes the same chemical reaction, albeit
at a slower pace, with water *vapor* that is present in the air. That reaction
happens only once -- in other words, after the grout has been exposed to
humidity for any length of time, it's no good any more. There's no practical
way to rescue the grout you have now; the best you can do is replace it. To
prevent the problem from recurring, store the unused grout in an airtight
container. That won't make it last forever, but it will extend the shelf life
considerably.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.