Today I was helping a friend finish some sheetrock, and we were using 90 minute setting compound. We went through two bags of that, and one bag of 45 minute stuff. We had a problem with the 90 setting too fast. Actually, it was looking like cottage cheese. Way less than 90 minutes. Sometimes in 20 or 30 minutes.
One time he used hot water, and we through that batch out after about 20 minutes and re-mixed with cold water. But it still happened too often. Why?
“When asked if you can do something, tell’em “Why certainly I can”, then get busy and find a way to do it.” T. Roosevelt
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Are you mixing it with a mixing blade in a drill? Potato mashers don't work well with powdered mixes. Variations in temperature and humidity can affect the set-up time. I generally mix hot mud 50-50 with regular mud. Set-up time stays about the same, but I like the way it trowels on better, and I like the way it sands better too. Blend the hot mud real good first, getting all the lumps out, then add the reg. mud and blend it in. We used to call it "spiking" the mud.
Did you clean your bucket between mixes?
What brand?
A great place for Information, Comraderie, and a sucker punch.
Remodeling Contractor just outside the Glass City.
Quittin' Time
I think it was sheetrock brand. Whatever HD sells, cuz that's where he does 95% of his buying. We used a drill motor and a spiral-blade paddle.
No, the bucket was not always cleaned out between mixes. Toward the end, I scraped out almost all of it, but it still occured. My friend likes to take short cuts, and he would tend to mix on top of whatever was left in the bucket. (Light bulb goes off in brain) Gee, maybe that's the problem ... contamination.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
If there was any leftover, I'd suspect that also.
A great place for Information, Comraderie, and a sucker punch.
Remodeling Contractor just outside the Glass City.
Quittin' Time
yeah, sounds like you figured it out. Bucket has to be squeaky-clean for each new batch.
Any residue will make it set alot faster. Bucket need to be cleaned after each use.
Headstong, I'll take on anyone!
I've had that happen on the first batch (and just about every other after as well,) and I use new buckets for each batch to minimize the problem, mixing it well. I haven't figured out why it does it yet, it could be contamination, but I'm not sure. It usually doesn't happen for about the first 15 minutes or so, so I thought that perhaps I was making the stuff too stiff. The thinner the mud, the less of a problem it is.
I think I'll try Huck's idea of mixing it with all-purpose mud; I didn't realize you could. If you come up with a definitive answer, let me know. The lumpy stuff trowels on terribly, causing more work prior to second coat.
"I am the master of my fate, I am the captain of my soul." Invictus, by Henley.
I mix it with all-purpose for the taping coat, then with topping for the last two coats
I just read the instructions last week and I thought it says right on the bag "Do not mix with other types of drywall compound" but I don't have the material in front of me. I think you are taking risks in mixing different types of compound that are not designed to be compatible.
Do you have any info on the durability of the joints using the franken-mud?
I've too noticed some batches of compound set quickly. I always thought it was contamination of already setting mud. I always assumed the almost complete chemical reaction of the old mud set off an accelerated reaction in the newly mixed mud. Not shure how much is required to do so, but it is the only solution I can think of. As stated temp has a lot to do with it too, but I kept the site cool just for lenght of workability.
TimYou buy a cheap tool twice and then you're still stuck with a cheap tool!
The reason why the bucket has to be clean is if any partially set mud is left in the bucket the little particles act as foci for the new mud to set. The same thing happens if you over mix a batch of hot mud.
Also remember to put water in first then powder. BTW, water temperature does not affect the setting time that much.
Ok, so what do you do when you have to mix up several batches? Use 3-4-5 different buckets, then not use those again until the next day? Cleaning hot mud buckets in a bank lobby at midnight is not an easy task.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
That's why we all have been saving our buckets. :)
Ok, so what do you do when you have to mix up several batches? Use 3-4-5 different buckets, then not use those again until the next day? Cleaning hot mud buckets in a bank lobby at midnight is not an easy task.
Since I usually only mix up a little bit at a time, I use a 2 gallon bucket with disposable liners. The liners are designed for the bucket and cost about $1.00 each. The Home Depot (Watchung Square mall, NJ) sells them.
Being disposable means that I avoid clean-up completely. I also use these buckets and liners for thinset, grout, small concrete repairs, etc.
-Don
I'm not supplying 3 guys, but when done I take the tools and bucket to the mixing station (sounds official) and pour in a couple inches of water out of the cleaning bucket. Clean the knives, brush clean the bucket, and pour the dirty water back into the cleaning bucket.
Now, I know that clean is the ticket, but I think your biggest problem is leftover mud and perhaps not starting with water, add mix........perhaps even not getting all the dry mix down in the bucket corner not mixed up. Over mixing can do it too (accelerate the set time). Dave the doctor of drywall scrapes down the bucket sides and discards but he's not into washing between mixes. He has no problem like you describe.
But then again, this from an older dumb carpenter. What's mooney's take on it.A great place for Information, Comraderie, and a sucker punch.
Remodeling Contractor just outside the Glass City.
Quittin' Time
Ok, now can you help me with my gravy ?
America is a country which produces citizens who will cross the ocean to fight for democracy but won't cross the street to vote.
I always start with water in the bucket, and too little powder, get a nice soupy mix, then add more powder. I learned years ago with a bucket of thinset that adding the powder first is a huge mistake. I (almost) never have a problem with unmixed thinset or durabond in the bottom of the bucket.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
When mudding, I always keep a trash box (usu. an empty mud box) and a sponge in a bucket of water handy, for cleaning tools between batches. A 6" blade should scrape the bucket pretty doggone clean when you're using up the last of the batch (any stuff that set up too fast goes in the trash) - then follow up with a sponge wipe-down from the water bucket. Takes a few seconds, and you're ready to mix the next batch.
This has me chuckling. I turned my friend Jim on to hot mud a few years back. He thought he'd found something really neat. Had a job that weekend helping his bro in law with a basement. Well heck, he called me Monday and he was disgruntled as all get out. "That durn stuff!" seems after the first batch, it kept setting too fast to get used, so they'd pitch it, remix it, and 20 minutes later, their 90 minute was a rock. I laughed. "Remember when I said you gotta get everything clean?" I asked. He'd missed that tidbit. Wasted several bags of mud in the process as well. Hey, at least, you ain't alone.
"If you pick up a starving dog and make him prosperous, he will not bite you. This is the principal difference between a dog and a man." - Mark Twain
Could be an old bag of mix.
I've taken to sifting the dry mix first thru a fine mesh screen (a mesh splatter guard for a frying pan). Also helps to make the mix very thin/watery at first then after mixing add more dry mix until the right consistancy. No lumps.
Everything clean as a whistle. Start with a few inches of cold water and add mix & water accordingly from there.
One of the reasons that bags set up so quickly is that the plaster in the mix has already been hydrated because of sitting around too long. If you plan to store any cement or plaster , the bag should be put inside a strong plastic bag and duct taped shut away from any moisture getting to it. Then it should be placed up off the floor in a dry area. Shelf life on this stuff is not very long and it should be bought when the stuff is fresh or a new load has arrived. Many times I will not buy plaster if it's the last of a batch because you know that it has been sitting in a damp bay for a while.