# setting type joint compound ready to paint in 90 minutes



## pman6

http://www.homedepot.com/p/Rapid-Se...oint-Compound-70020009/202207962#.UYY0xbU3uHc

This product says it's a 20 minute compound, and ready to paint in 90 minutes.

are all setting type compounds ready to paint in 2 hours?


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## user1007

I do not know this brand but you can buy hot mud by the curing times (do realize the curing starts the second you add moisture so allow for time to mix). They start at 5 minute and go up to 120 minute---5, 20, 45, 60, 90 and 120---for example. Not all places will carry all but 5, 20, 45, 90 are pretty common. If you have not used it before, you may find 45 a good starting point. Mix in small batches---like a drywall pan full at a time unless you are taping and can work with part of a bucket full before it sets up. 










5 minute is wonderful stuff if you can work really fast or have a helper mixing mud for you. 5 minute sets up near instantly. Its advantage is you can sand and prime it in just a few minutes. I had it on hand for quick, small patches but usually used 20 or 45. 

Anyhow, your other question as to how soon you paint what you are consideing will depend somewhat on how thick you are using it. A skim coat of 20 or 45 should certainly be ready to sand and prime in a couple hours, or closer to the cure time for that matter, unless you have deep patching going on. It will most certainly dry faster than pre-mix mud and you can control the consistency. 

Dry mud is a little harder to sand so you want to be sure to scrape off excess as much as you can.

Pre-mix mud is still a better choice for large taping jobs just because it is more convenient and you do not have to race it curing on you. Again, if you have someone helping you and use a hot mud with slower cure time it may work for you too. If you really cannot wait out pre-mix drying hot mud is your only other option. 

Buy an airtight Rubbermaid type container to store leftover powder.


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## ToolSeeker

I agree with SDS. The one mistake people make is when the mud starts to get thick they add more water. If you mix it too thin it will lose it's strength. And you must clean your tools and pan between batches. This is called setting or hot mud,as opposed to drying mud, because it sets by a chemical reaction. 
and as SDS said once water hits it this reaction starts and can't be stopped. The reason to clean between batches is any thing left on the tools or in the pan will greatly accelerate the process, as will mixing it with hot water. That ends HOT MUD 101:laughing:
I have never used or heard of the product you showed so I really can't comment on it.


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## chemman

Just because hot mud has set up doesn't mean it still doesn't have moisture in it that needs to evaporate. Might cause adhesion problems. I suggest waiting until the next day. It would be a shame to have the paint peel off after all that tedious work painting just to save waiting overnight.


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## ToolSeeker

chemman said:


> Just because hot mud has set up doesn't mean it still doesn't have moisture in it that needs to evaporate. Might cause adhesion problems. I suggest waiting until the next day. It would be a shame to have the paint peel off after all that tedious work painting just to save waiting overnight.


You are absolutely correct and I should have mentioned it. Just because it's hard does not mean it is dry.


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## pman6

well, I have some fake 1960's wood panels to remove from the drywall.

hopefully I can skim coat over the glue residue with 90 minute compound and primer the same day.


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## oh'mike

You will be pushing the job to fast----

If you are skim coating over dry adhesive--I would use the 90 minute for the first coat (or two) the top with Easy Sand----wait until that is dry--then sand and prime---
90 minute mud is hard to sand---

will waiting one day for the mud to dry cause you a problem?


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## ToolSeeker

Since your doing a _skim_ coat it is thin and will not take that long to dry. Just skim it with regular mud easier to work with and easier to sand.


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## chrisn

pman6 said:


> http://www.homedepot.com/p/Rapid-Se...oint-Compound-70020009/202207962#.UYY0xbU3uHc
> 
> This product says it's a 20 minute compound, and ready to paint in 90 minutes.
> 
> are all setting type compounds ready to paint in 2 hours?[/QUOTE]
> 
> 
> no:no:


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## pman6

oh'mike said:


> You will be pushing the job to fast----
> 
> If you are skim coating over dry adhesive--I would use the 90 minute for the first coat (or two) the top with Easy Sand----wait until that is dry--then sand and prime---
> 90 minute mud is hard to sand---



yeah, I was planning to use easy sand 90 only.


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## Amilsmithly

I've found that even the 20 minute stays a bit moist for hours. You can tell by the grayish color that eventually turns white when it's dry. 

I mix it with as little water as possible and this still happens.

A tip, for small patches mix it in a ziplock bag, this allows you to kneed it really well and it's easy to clean.


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## Dorado

It's weird that you have to add water to "setting" compound. I just bought a bag of the 90 minute easy sand and it says "low shrinkage" meaning it shrinks. I wonder if I should prime the drywall and the other substrates I'm using it on so the water will evaporate more into the air instead of being absorbed into building materials and causing cracking rather than sinking. Sinking can be fixed more easily with another coat.


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## pman6

Dorado said:


> I wonder if I should prime the drywall


I have read instructions that say to put primer before skim coats.


I'm going to bring a fan for faster drying.


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## ToolSeeker

Setting mud dries by chemical reaction vs drying mud that dries by evaporation setting mud is used because it gets hard and you can put a second coat on without it being dry. This is so you can put a couple coats on in one day and save trips to the site. But yes leave it over night before you prime and paint. A lot of people get bubbles and peeling paint by not letting it dry. And fans will do no good because once the top has set the air can't get to it anyway.


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## bjbatlanta

You CAN paint in the time frame you're talking about, but I would highly recommend against it. Setting compound often leaves more imperfections than ready-mix. I would recommend a skim with regular ready-mix prior to paint....


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