# Mixing Hot mud with plus 3



## naptown CR (Feb 20, 2009)

Here's a solution I have used in this situation sucessfully. If a repair whatever is going to take several coats or use a lot of mud I will mix enough 90 to do the job. I will then add some aluminum sulphate to the mud i put in my pan. This reduces the PH of the mud and will turn the 90 into 20 45 or 5 if you want depending on how much you add. This means I only mix one batch of mud and control set time in my pan. You can get it at most garden or farm supply stores and is much less expensive than the accelerator you would buy from the drywall supplier. Mix it in an old soda bottle with some water and add to the mud in the pan. It will take a little practice to get the right amount for the amount of time youu want it to set in but is a real time saver over cleaning the pans and buckets and mixing multiple batches.


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## BillD (Jun 9, 2008)

Anyone use Lafarge Rapid Coat? I have used it on several jobs and I like the fact that it works like regular mud but dries faster than green or +3.

Bill


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## SheetrockDoc (Mar 7, 2010)

Nope...never tried it.

I have a friend that used it a lot for a while...he told me to stay away from it do to call backs, but it might just be that he is a part time taper??

The stuff is very spendy here in Maine, can only get it at Hardware stores, so I have yet to venture out on that one.

Give me some wisdom about the product please :notworthy I am all ears


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## ProWallGuy (Oct 17, 2003)

I'm not a drywaller, but just a dumb-ass paperhanger, but I personally wouldn't mix the two. One dries by evaporation, and the other dries through a chemical process. Not really made for each other. I do know that hot mud really changes up the ph of a surface, and can cause all kinds of problems with an acrylic primer/paint. I generally use the hot mud to fill most of the repair areas, and then do a regular mud skim over the top of that so it doesn't interfere with my wallcovering primer.


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## SheetrockDoc (Mar 7, 2010)

Ah Ha...Now the truth comes out, I knew my gut was telling me that mixing chemicals was a no no...

Any more wisdom for the Doc? :notworthy


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## MUDBUCKET (Jun 9, 2008)

I've mixed easysand 45 and 90 with topping mud for filling beads and butts for years ,never had any issues with it,a lot less shrinkage on corner bead than straight topping, just make sure you do a final coat of straight topping mud for ease of sanding and painting. Easy sand will "flash" through paint and you will always see it.


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## SheetrockDoc (Mar 7, 2010)

Thanks for you 2 cents MB...starting to see the light here, any more takers on edjucating The Doc :notworthy


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## BillD (Jun 9, 2008)

SheetrockDoc said:


> Nope...never tried it.
> 
> I have a friend that used it a lot for a while...he told me to stay away from it do to call backs, but it might just be that he is a part time taper??
> 
> ...


I only used it on small jobs and had no problems. When I was a commercial super my drywaller used it all the time on large jobs and I do not recall having any problems with it there either.

Bill


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## Big Shoe (Jun 16, 2008)

ProWallGuy said:


> I'm not a drywaller, but just a dumb-ass paperhanger, but I personally wouldn't mix the two. One dries by evaporation, and the other dries through a chemical process. Not really made for each other. I do know that hot mud really changes up the ph of a surface, and can cause all kinds of problems with an acrylic primer/paint. I generally use the hot mud to fill most of the repair areas, and then do a regular mud skim over the top of that so it doesn't interfere with my wallcovering primer.


That has always been my take on this issue of mixing the two. I've seen it done over the years mostly on first coats of corner bead. But like you say ,the reg mud still has to dry.

I've never tried it,never had to or wanted to. Someday maybe.:surrender:


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## Axecutioner-B (Jan 28, 2010)

SheetrockDoc said:


> I often wondered...the manufacturer says do not mix the two togeather, but if people are having good luck and it has proven to last a year without call backs, I am up for it.
> The plus 3 is so easy to work with...I am able to one coat everything because it sets up very fast if the coats are thin, no drag marks, puddles or ridges.
> I typically do a 4 coat finish, which leaves hardly any sanding on small projects...adding hot mud would make it a dream I am sure, just kinda leary about mixing different chemical compounds togeather without some kind of blessing :detective: Guess I will do a little homework before trying it


I've read the back of a bag of 20 minute & it says NOT TO MIX WITH ANYTHING (& i think the +3 says the same)!! ... BUT like i said earlier in the thread, i learned this from what i consider a first class mud slinger & he has been mixing hot mud with +3 for years. IMO if there were going to be an actual problem with the mix it should/would happen right away because both ingredients are stable over time. I would recommend you experiment with it some in a small way to see if you like it. The less 20 minute you put in it the slower it sets & vice versa. I use this method almost everyday & i cant imagine doing it any other way, especially for these peice-rate apartment remodels. The faster i can get one done the faster i can start the next one & so on... Good luck !! Let us know how it works for you


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## Tim0282 (Dec 11, 2007)

Don't see that it does any good to mix the two. Your fast set still sets fast and your air dry still has to dry. So you only have part of the mud set. The other part still has to dry. :shifty:


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## SheetrockDoc (Mar 7, 2010)

6 of one half dozen of another...hmmm, guess I will try it on my own home first and see if it makes me happy...No sense in experimenting on a lifelong customers home :thumbsup:

Thanks for the input guys, I will keep you informed :thumbup:


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## SheetrockDoc (Mar 7, 2010)

I decided to test the hot mud and plus 3 mixture...lots of cracks, dries to fast and does not bond well...Practiced on one of the rooms in my own house where I am doing a remodel project.

Took 2 hours to dry thouroughly with 90 minuate that I had kicking around...Im thinking I like the old fashion way better.




> Rome was not built in a day, but it has stood the test of time


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## Drywall Meister (Nov 14, 2009)

While back I meet a guy who added Japan Drier to plus3 in each pan of mud (hand taping etc). He liked adding the japan drier because it was easy to add a few cap-fulls to a pan of mud; fast, clean and it saved him time on mixing hot mud. Never did see his results and never did try this myself but has anyone ever tried adding Japan Drier to plus3??


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## Tim0282 (Dec 11, 2007)

Surely not... :no:


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## Axecutioner-B (Jan 28, 2010)

SheetrockDoc said:


> I decided to test the hot mud and plus 3 mixture...lots of cracks, dries to fast and does not bond well...Practiced on one of the rooms in my own house where I am doing a remodel project.
> 
> Took 2 hours to dry thouroughly with 90 minuate that I had kicking around...Im thinking I like the old fashion way better.


How did you mix it? Why were there cracks, what were you mudding over? How thick? Does not bond well to what?

I NEVER have any of those problems. No cracking, no por bond etc.. I do believe it would take well over 90 minutes to set if you are mixing +3 with 90 minute, but even mixing with 90 minute there should be no good reason for any cracks  Hot mud doesnt crack as easy as +3 !!


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## SheetrockDoc (Mar 7, 2010)

Existing drywall...I only mixed enough 90 in to turn it to dough then thined with water and whipped it up to my normal consistancy.

The tape layed flat when bedding, but when second coat dried, the outside edges of the tape cracked...the rest of the wall looked ok, but every single tape did he same thing.

I only bedded the tape with the hot mixture...ran second coat with normal plus 3...then it cracked. The 90 I used was easy sand, maybe the two do not like eachother? Should I try Durabond since it hardens up more?


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## raven2006 (Dec 19, 2006)

So we're at at least 100 boxes of mud and 30 bags of concrete fill on our 10,000 sq feet of drywall house. Most walls have a good half inch of mud over the whole thing. There's a total of at least 4 coats, usually five. The first two are 3/4 box of mud to 1/4 concrete fill. If we'd used straight mud, we'd be waiting a year for it to dry..if we used straight concrete fill, well that'd be extremely expensive. But the two together work great, it does set quickly, but also dries faster, usually sandable the next day. While a half inch of regular mud would take days, especially in this cold house. It's also much more stable, there's less shrinkage too. We've used this method lots on high end houses, absolutely no problems. This house is costing like 7 million just to build, so we are using only tried and true methods.


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## SheetrockDoc (Mar 7, 2010)

Thanks Raven, I guess I will try it again, Im just not use to mud cracking when it dries. My coats are thin and when finish coat goes on, I have very little sanding. 
Does your mud mix crack when it dries?
I give a 1 year warantee on cracking and have had 1 call back in 10 years that I fixed for free, so I really dont want issues. Spread a little love here and give me heads up as to how you mix it. Send a private message if you dont want to give away a trade secret to a DIY


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## raven2006 (Dec 19, 2006)

This definitly isn't our usual method, we also generally put on about 3 coats of regular mud, they are thin and we have very little sanding as well. But with this house, alot of the walls are concrete, so in a room they will have two concrete walls and two drywall walls. In the kitchen it's all concrete, with a drywall ceiling, etc. Around the edges they have put a metal sort of bead to finish the drywall against the concrete. Now they want the walls perfectly even and flat, to the normal person filling the edging as you would a bead and filling flats and butts the usual way would be ok, but here they take a 8 ft straight edge and put it from one bead/edging to the other and there's a gap along the whole lenght of the wall. It's amazing the crookedness you'd find in a wall when you use a straight edge that big. There's a hallway that's about 40 ft long and 15 ft high, and the edging is around all four doors and at the top and bottom and around the sides, so the whole thing has to be filled to be level with the edging. Hard to explain, i will put some pictures up later...but bottom line..lots of filling..and for the foundation coat we are using the conrete fill/mud mix. It hasn't cracked at all, and once we get the wall to a fairly even state, then we start skimming it with the regular mud. On normal jobs, we don't use this as much, just for when we come across large fills.


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