# drying time



## hozman (Oct 31, 2019)

i am using sheetrock 20 to patch a large hole in the celing. I used the mesh tape too. How long does it take to dry so i can sand it, or put another coat on. Also i need to prime and paint. Just wondering how long this job will take.


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## mark sr (Jun 13, 2017)

It should dry in about 20 minutes although it might take twice that long before you can do any light sanding.


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## hozman (Oct 31, 2019)

thanks. what about paint? how long does that take to dry?


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## mark sr (Jun 13, 2017)

It's best to wait a day before applying paint although I suppose priming it would be ok. Hot mud tends to 'burn' the paint when applied too soon .... but if it does - another coat of paint fixes it.


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## jeffnc (Apr 1, 2011)

It absolutely does NOT dry in 20 minutes. It depends on temperature, humidity and how much mixing you did.


It will set in approximately 20-40 minutes, depending on temperature and mixing (including temperature of the water you added.)


Drying can take from several hours to several days, depending. You said your holes were large, not really clear what that means.


So, you can put another coat on in about 20 minutes. This is the whole point of setting compound. However, in terms of sanding it's no different from regular premixed drying compound. So, you want to put your 3 coats on in about an hour and a half (what would normally take about 3 days with premixed compound.) Obviously you don't want to sand in between coats or else you lose the advantage of using setting compound. If you wait until it dries so you can sand between coats, then you might as well use premixed compound.


However you did use mesh tape instead of paper tape. Mesh tape is weaker, and setting compound is stronger than drying compound, and required for mesh tape. So you have to take all that into account when you decide what kind of joint compound to use.


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## siffleur (Aug 19, 2013)

*Which product?*



hozman said:


> i am using sheetrock 20 to patch a large hole in the celing. I used the mesh tape too. How long does it take to dry so i can sand it, or put another coat on. Also i need to prime and paint. Just wondering how long this job will take.


hozman, can you post a link to the Sheetrock product you are using?

siffleur


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## jeffnc (Apr 1, 2011)

*Re: Which product?*



siffleur said:


> hozman, can you post a link to the Sheetrock product you are using



Are you aware of multiple products called Sheetrock 20? I am not.


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## hozman (Oct 31, 2019)

https://www.homedepot.ca/product/sheetrock-20-setting-type-joint-compound-11-kg-bag/1000414533


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## jeffnc (Apr 1, 2011)

https://www.usg.com/content/dam/USG...mpound-data-sheet-en-can-patch-and-repair.pdf


Note:
-  If setting-type drywall compound dries before it sets, bond failure may result.
- Setting time is a range that can be affected by temperature, relative humidly and wet-thickness. Application to porous surface or at less than 3 mm (1/8 in.) thickness may prevent chemical setting and bond.


In other words, this stuff is similar to concrete, in that it achieves strength through a chemical process (not a drying process) and should stay damp until it is set. It is not like paint, or drying type joint compound.


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## hozman (Oct 31, 2019)

what is the difference between drying and setting? I thought it dries first then takes longer to set.


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## mark sr (Jun 13, 2017)

When it sets the mud is no longer workable but still soft enough to be gouged with your finger or knife. Dry means it's no longer pliable at all.


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## siffleur (Aug 19, 2013)

*Sheetrock vs Durabond*



jeffnc said:


> https://www.usg.com/content/dam/USG...mpound-data-sheet-en-can-patch-and-repair.pdf
> 
> 
> Note:
> ...


jeffnc, not totally sure, but I am guessing that the CGC Sheetrock is the Canadian version of USG Easy Sand and the USG Durabond is the same as CGC Durabond:

http://www.commercialdrywall.com/du...mpounds/cgc-128/joint-compounds/products.html

siffleur


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## jeffnc (Apr 1, 2011)

*Re: Sheetrock vs Durabond*



siffleur said:


> jeffnc, not totally sure, but I am guessing that the CGC Sheetrock is the Canadian version of USG Easy Sand and the USG Durabond is the same as CGC Durabond:
> 
> http://www.commercialdrywall.com/du...mpounds/cgc-128/joint-compounds/products.html
> 
> siffleur



Durabond is Durabond and Sheetrock is Sheetrock. Sheetrock is the Easy Sand. He said Sheetrock 20. Durabond does not come in 20. Durabond is hard as concrete, Sheetrock Easy Sand is only easy sanding compared to Durabond, not regular premixed All Purpose.


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## jeffnc (Apr 1, 2011)

hozman said:


> what is the difference between drying and setting? I thought it dries first then takes longer to set.



Absolutely not with respect to joint compound - just the opposite.

OK, let's get the basics here: drying and setting 101.


There are many materials that get applied and then harden. Examples: paint, grout, thinset, concrete, caulk, joint compound, glue, epoxy.



All of these materials vary in the way in which they harden. Some contain water and harden as water evaporates. Some undergo a chemical process and harden based on that chemical reaction. Some of these also contain water, but that is not how it hardens.

When they pour concrete, have you ever noticed they continue to spray it down with water for a week or so while it sets or cures? That is because it is supposed to stay damp for the chemical process to make it hardest. Drying does not make it harden, in fact it makes it weaker if it gets dry before it's cured (just like setting type joint compound, and other things.)



Water based paint on the other hand hardens by drying. Same with acrylic caulks and some glues (like Elmer's glue).


Joint compound comes in 2 forms: drying and setting. Both have water in them (just like concrete does). But for the drying type, water evaporation is what hardens it. For the setting type, it has different chemicals that hardens it. The water is just a vehicle for smoothing it, not for drying and making it hard.


The different types of compound, such as Sheetrock 5, 20, 45 and 90, have different amounts of these chemicals - the more it has, the faster it sets.


The premixed compound in the big bucket can only be drying compound. Obviously it can't be setting compound because as soon as they mixed it at the factory it would harden. Setting compound is _always_ dry powder and you have to mix it with water. However drying compound can also come as a powder that you mix with water. This is much less commonly used because it's a hassle to mix, but I suppose it's lighter to carry large quantities than the heavy premixed buckets.


Which should you use?


If you use drying compound, you need to wait until it dries for it to harden, which means you've got to wait about 24 hours between coats, depending. But you don't have to mess with mixing it and cleaning a paddle and bucket, etc.


Setting compound is stronger. Mesh tape is weak, and so you must use setting compound with mesh tape or else you run the risk of cracking joints. If you use drying compound you should use paper tape for strength (or else FibaFuse). Also setting compound hardens up very quickly (although it doesn't dry any faster than drying compound). Therefore you can put on 3 coats in one day. But you still have to wait at least 24 hours normally before you sand. Sanding wet compound just clogs up your sander, no matter how hard it gets.


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## siffleur (Aug 19, 2013)

*Re: Sheetrock vs Durabond*



jeffnc said:


> Durabond is Durabond and Sheetrock is Sheetrock. Sheetrock is the Easy Sand. He said Sheetrock 20. Durabond does not come in 20. Durabond is hard as concrete, Sheetrock Easy Sand is only easy sanding compared to Durabond, not regular premixed All Purpose.


Here in the Chicago are we have Durabond 20:

https://www.usg.com/content/usgcom/...sheetrock-durabond-joint-compound.381710.html

siffleur


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## mark sr (Jun 13, 2017)

I've also used the Durabond 20 minute mud. It's my preferred setting compound although over the last 10 yrs or so it's gotten hard to find locally.


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## jeffnc (Apr 1, 2011)

*Re: Sheetrock vs Durabond*



siffleur said:


> Here in the Chicago are we have Durabond 20:
> 
> https://www.usg.com/content/usgcom/...sheetrock-durabond-joint-compound.381710.html
> 
> siffleur



I stand corrected.

Upon further research, it also leaves me wondering why they even make this product.
https://www.usg.com/content/usgcom/...nt-compounds/sheetrock-mh-joint-compound.html


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## siffleur (Aug 19, 2013)

*Re: Sheetrock vs Durabond*



jeffnc said:


> I stand corrected.
> 
> Upon further research, it also leaves me wondering why they even make this product.
> https://www.usg.com/content/usgcom/...nt-compounds/sheetrock-mh-joint-compound.html


This is the first I have ever heard of Tuf-Set 20.

siffleur


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## ClarenceBauer (Mar 4, 2005)

Basic mixture is the same for all of the setting compounds.
Durabond 20 basic mix has less Mica 
Durabond 45 has perlite added
Durabond 90 has Polymer & Silica added
Tuf Set has a higher amount of the setting chemical.
JEFFNC has it about as close as you will get for setting & curing temp., moisture will have the most to due with drying.
When we would mix our plaster on a mortar board we would start with Lime Putty, Water, Guaging Plaster & Moulding Plaster.
A basic mix would be lime putty 60%
Water to fill the inside of the Lime ring, in side of lime ring 30 inches Dia. Lime ring walls 4 inches high & 6 inches wide. Than add Guaging Plaster until all water is absorbed Than add about a good double hand full of moulding Plaster.
The above mixture would give us about 60 min. to work it. If any thing else was added like sand , Mica or perlite it would slow the set time. Now to increase the set time we could use dirty water ( water used to cleanup tools ) also used hot water to increase the set. Aluminite would also make for a very rapid set. To decrease we would add Cream of Tartar like used for cooking.
Most things added to a plaster mix will retard the set time.


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## jeffnc (Apr 1, 2011)

Dang, you are old school. I know next to nothing about plaster, other than it sets!


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## Fman (Nov 9, 2018)

I worked for a guy who was wrapped really tight. He was a YUGE fan of 5 minute mud cause he liked things to be done asfastaspossible!!! 5 minute mud has it's uses but, it;s not very practical. Anyway, we had some night work to do and he hands me a bag of Sheetrock 5 minute setting compound. Problem was, I had 4 floors in an office building with various offices here and there, all of which had pinholes to fill. This was a job for spackle. I told him so but, him being the boss, he didn't want to hear that. If I had had spackle on my truck, I woulda been fine. I was about 10 minutes from home, BUT, with no key for the building, I could not in good conscience leave the building with the door ajar. Long story somewhat shorter, I wasted a lot of mud running around trying to fill the pinholes before the mud stiffened in the pan. I really should have walked that night because the guy did not get any better and I knew he wouldn't. He wasn't a painter but you couldn't tell him anything. I had 20 years at the time and his foreman had even more than me and he couldn't tell him nothing either. When I told foreman the story he just shrugged and said: "If they made one minute mud he'd buy it!" He would have too!

Moral of the story- take your time! The work will still be there while the 45 or 90 sets and dries and there is always something else to do in the meantime. 

The guy who was my boss? He went back to smoking crack and drinking after being clean for several years years. No surprise he liked that quick high.


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## jeffnc (Apr 1, 2011)

Yeah, 5 minute is really for very small patches. You have enough flexibility with water temperature that you can mess with the setting times for 20 or 45.


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