mold in joint compound

[BobShep]

Has anyone else had this problem?
I'm a finish carp, and don't use joint compound on a regular basis. But the last two buckets of +3 ended up getting moldy after sitting around for a month or so. Both were opened, and maybe 1/4 to 1/2 empty. I seal them up, and store them in my basement.The first bucket I threw out when I saw the mold , and I bought the second one, thinking that the mold in the first one was a fluke.
Today I opened the 2nd bucket for a patch in my own house to see a layer of green mold on top.
I've had part buckets of compound sit around for months without getting moldy. Did USG change the formula somehow?
And how can I keep any new mud from getting moldy? I know that a bucket of mud isn't all that expensive, but I dislike wasting materials. Will mixing in some bleach affect the compound, and keep the mold from growing?

Thanks, Bob

[Toolwhore]

Re: mold in joint compound

Bob;

Go to the USG website. I was looking at it the other day and it has info on storage and mold. If I remember correctly, it said if it has mold, to throw it away.
www.usg.com
Click on construction handbook.

[Mike from NH]

Re: mold in joint compound

I have a friend that had me tape a closet for him about 3 yrs ago. He had an old bucket of USG green lid in his basement that was I would say 10 yrs old, it didnt have the current label on the bucket it was that old!. It was about 2/3 of a bucket, no mold so we used it. No problems reported yet, it has been 3 years now. So good chance the formula has changed, like removal of a mold additive that was always in it to then come out with a new mud with a mold additive and charge extra for it?

[BobShep]

Re: mold in joint compound

That's what I was thinking.
I've been in this business over 30 years, and its just these last 2 buckets that I've had problems with.
It looks like I'll be wasting a lot of joint compound in the future. I'm going to have to start using setting compound again.

[mudmastah]

Re: mold in joint compound

I will dump a little bleach in it, mix and go with it, it does not take much. I don't know if this is right or not but I don't like wasting materials either. Usually we get into a mold situation in the warm summer months with the stuff sitting in the back of the box truck. Sometimes I will forget about a mix of orange peel and it will get soupy black with a mother floating on top of it, that stuff gets pitched. Good luck, Ed.

www.themudmasters.com

[Ruud_Dawg]

Re: mold in joint compound

Hey Bob. I've been essentially rebuilding my house for the past few years due to damagd caused by a roof leak and also a poor attempt by a former owner to finish the basement. The secret for keeping your compound mold free is so easy you will probably kick yourself for not thinking of it.
Take a sheet of cling wrap and press it down firmly on top of the compound, making sure to get the bigger air bubbles out. I've found this to be a perfect solution so far. When you want to use it again, pull off the plastic wrap [some compound will come with it but that's okay], fold it up and toss it. I use a fresh piece of plastic wrap each time I reseal the bucket.
Good Luck!!!

[frenchie]

Re: mold in joint compound

I don't think they changed the formula. I've seen mold form in old half-buckets, 10-15 years ago.

I was taught, when you close up a bucket of mud for a long time, to pour a little water on top of the compound first. Not a lot, just enough to cover the surface, to avoid getting a crust or little ****z when you re-open it. A capful or two of bleach, mixed into that water, prevents any mold growth.

Nowadays I just use setting, so it's a non-issue.

[mudmastah]

Re: mold in joint compound

I add a little bleach and use it...smells good, peace Ed.

www.themudmasters.com

[Joepro0000]

Re: mold in joint compound

I'm sure everyday there trying to find cheaper products/chemicals to make a less expensive formula to save money. Look at Coca Cola, they changed their formula so many times to save a few bucks.

[DickyD]

Re: mold in joint compound

I see that Ruud Dawg recommends placing plastic wrap on the surface of unused mud. I've been doing that for years with success. However, I recently opened a USG Green Cover that was half used. The mud is probably five years old. Upon opening, the inside surfaces of the bucket was a petri dish of black mold. The covered mud showed black spots of mold. The mud has been stored in a cool dry basement. Having stored mud in this manner for the past forty years without a problem, I'm tending to think that the formula has changed. BTW, the mud was still of good consistency, but black mold, not in my house!

[Tbone613]

I purchased a 2kg bucket of mud and used roughly half of it and then just thru the lid back and stored it for probebly over a year. When I took it out again to use it was perfectly fine no mold or anything. It had started to dry out a bit so I just added I small amount of water and mixed it up and it worked perfectly. I had maybe 20% of mud left. This time I decided to put cling wrap over the remainder to try to keep it from drying out. I took it back out today it was only stored for 6 months and it had black mold all over the top layer. So I think that means it's not a different formula it was the same batch. I feel it might be best to let it dry out a bit and just add water when plan to reuse since the mold needs moisture to grow.

[Michael Mraz]

I had 75% of a 5-gallon bucket of USG all-purpose that had been "hiding" for about 10 years. Opened it up a few weeks ago and gave it a stir thinking that I'd use it for a small (closet) remodel job. It was fine when I opened it, no mold whatsoever. A week later I opened it again to do some taping and there were mold spots on the surface. I'm going to have to pitch it unfortunately.

Can anyone recommend a lightweight easy-sanding compound in powder form? The setting compound I use to embed the tape is too hard for the fill and final coats. Thanks.

[dany ethical]

Add little beach and use it and it's gonna smell good.

[Kevin Skogg]

One thing I question. The source of the mold is not in the wall, mold needs the water to be active. Mold spore are floating all around, that's why they get in bucket. Really, if the wall is dry and no additional source, the mold from the bucket wouldn't propagate without moisture. If there is moisture there, the mold in the air would find it anyway.

Just asking, not making any claims.