# Airdry & Setting Muds.



## cazna (Mar 28, 2010)

My baby girl has been moaning every 40mins all night, Nappy rash and some tummy ache i think, so its 5am so i thought i may as well start this thread i have been thinking about.

Notice its heading it Airdry AND Setting muds, Not Airdary VS Setting muds. Depending on your climate you will use either to suit your needs so no fighting please, Lol yeah right, ding ding goes the bell 

I dont think anyone is right or wrong whichever they use, They both have there place but im interesting to who uses what, and were and for what reasons.

I used one tape coat setting, 2nd coat setting then one air dry system all by hand for 10 years, and had almost no problems. This is common practice in nz and oz i think.
Been on the airdry stuff and machine tools for about 3 years, had a few problems, Mostly shrinkage issues due to cold damp weather then underfloor heating cooking the houses out, Its not common practice to heat and dehumd homes here NZ or run machine tools.

Some of you say hot muds cause trouble, some of you say its great as it does not shrink, Some of you add hotmud to your air drying to hold back shrinkage. I have heard airdry stuff keeps on shrinking for years.

So hotmuds expand when setting, and airdry shrinks when drying, Both have advantages.

It been interesting to read how you guys are doing things, Its all a bit scattered around the threads so please post here what you prefer and why so we can get an overall picture of whats getting used.


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## M T Buckets Painting (Nov 27, 2010)

I do use setting compound for pre-filling, just so that I can get on with the taping process. I strongly prefer air drying compounds for everything else. Most of the time I don't need dry time to be that quick. Regular compounds are so much easier to work with. They sand much easier, don't flash, etc. I have on a couple of occasions have had hot muds kick off on me in minutes. When 90 minute mud is rock hard in 5 or 10 minutes, it is a pain in the backside.

On the occasion that I do use hot muds for coating, I mix them differently. I will mix in a 2 gallon bucket with a paint mixer on a drill. I also add a couple squirts of dish soap and two 5 inch knives of all purpose. By doing this I get a more workable compound that is mixed better. The all purpose doesn't seem to affect the set time too much either, since proportionally I am not adding that much dilution with it. When mixed as I stated the mud may last a little longer before setting but, not that much. It sands a heck of alot easier and tools off much better.

I guess that my mix of all purpose to hot mud would be about one pint of AP per gallon of hot mud.

The only time that I do use the afore mentioned compound mixture is on a small room or repair that I want to get done in one day. Or else I would be using air dry compound.

The bottom line is that air drying compounds are the way to go in my opinion. I don't have any problems with them not drying, with the exception of a few angles on exterior walls from time to time. Nothing that a fan wouldn't take care of.


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## cdwoodcox (Jan 3, 2011)

I use a combination of both. All prefill is done with quickset, all taping is done with all purpose. All first coat is done with quickset, after first coat second and third coat are done with plus 3. with the exception of angles which are skimmed while taping and then ran with plus 3 through angle box. All vinyl bead is ran twice with all purpose then third coated with plus 3.


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## mudslingr (Jul 18, 2010)

I use hot mud for pre-filling all the time. I consider 1/3 of a bag (15kg) to be average on a decently boarded 5,000sq or less. 
On smaller commercial jobs I'll use mesh on the true flats (usually stand ups) and load them with 90 or 45 depending on how many there are so I can sling a coat of AP on the same day. 
When I do vinyl arches I always use hot mud for the first coat. I find that arches usually have a deeper fill so using some 45 is great. You really have to bash that thing to scar it when it's done. Durabond is also great for arches. That stuff is pretty darn hard when dry but doesn't sand easily so you have to get it right the first time.
A quick fill on any bullnose adapters with hot mud also makes the first coat of mud fill nicer and keeps it solidly in place.
I rarely do angles with hot muds but if I'm just doing a small washroom I'll tape it all out with 90 so I can coat it with mud when it sets.

As far as AP goes I use it for everything else other than taping mud which has more glue in it.
No water for first coat on beads or butts which helps tremendously against shrinkage.
I'll add water to AP when doing flats depending on which brand I'm given to use. Synko can get up to 4 pop cans of water. It's terrible IMO. One and a half cans and maybe a remix in between is ideal for me.
My machine mud gets whatever amount of water is necessary on any given day depending on heat and humidity.


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## moore (Dec 2, 2010)

M T Buckets Painting said:


> I do use setting compound for pre-filling, just so that I can get on with the taping process. I strongly prefer air drying compounds for everything else. Most of the time I don't need dry time to be that quick. Regular compounds are so much easier to work with. They sand much easier, don't flash, etc. I have on a couple of occasions have had hot muds kick off on me in minutes. When 90 minute mud is rock hard in 5 or 10 minutes, it is a pain in the backside.
> 
> On the occasion that I do use hot muds for coating, I mix them differently. I will mix in a 2 gallon bucket with a paint mixer on a drill. I also add a couple squirts of dish soap and two 5 inch knives of all purpose. By doing this I get a more workable compound that is mixed better. The all purpose doesn't seem to affect the set time too much either, since proportionally I am not adding that much dilution with it. When mixed as I stated the mud may last a little longer before setting but, not that much. It sands a heck of alot easier and tools off much better.
> 
> ...


I'll try that... thanks


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## moore (Dec 2, 2010)

I tape all seams and butts with 90. year round . I never spot screws with hot mud,I never let hot mud touch the no-coat.. In the dead of winter ,,,, house , no heat ,,yes I'll use a bit more hot mud than i should . I have too. On butts ,and seams [block coat only] ,,,, AIR DRY MUD:blink:. I use bucket mud a/p as often as possible ,hot mud is a pain,,,yes ,and I wish I didn't have to use it ,but I do.. with the crap material ,and weather it's a must. Just a little diddy..... other d/c here have lots of call backs due to cracks in seams ,and peaked butts,, my call backs are truss lift[ walking trusses]
hot mud has it's place,,, and I'm still learning where it can and cannot be applied .Most ALL machine finishers will say hot mud is a crap,a no no .... that's because it can not run through that bazooka , or boxes .. I get it. 
my biggest problem have taping with hot mud ,, It does swell . with butts it's a bitch ,,, but butts are a bitch anyway.


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## 2buckcanuck (Jul 9, 2010)

All purpose all the way









I even pre-fill with it, with straight stiff right out of the box, why bother with the hot muds. Drywall is specifically designed so the mud dries faster. The paper design is a big secret to those drywall companies, so....the rock draws the moisture from the one side, well air dries the other side. With in the 1st half hour of pre-filling , the mud will shrink back to as far as it will go, then dry.

Other reasons why ????
you go through less water
your not constantly cleaning tools
No matter how well you clean your tools and buckets, lumps of hotmud magically appear in your all purpose:furious:
hotmuds cost more than AP
It's too time consuming
I want my tape to shrink, not expand
I want to control the product, Not the product control me,,,,example,, coffee truck shows up, but your F'n mud is setting up
I hate mixing mud (that's why there's a 2buckjr) then I'm to screw with powder mixes.....nope
the sanding properties are too drastically different between AP and HM....ex...miss one little lift mark of HM, then good luck at sanding that out from underneath of the AP.

The only time I use hotmud, and the captain has stated this before, is as a accelerator. I will mix one or two cups of hotmud into the AP well mixing. it does help with the drying process. Also , your bucket of AP will not set up on you, you can remix it the next day, but if you put 4 cups to the AP, (if I remember right) it will set up like a rock. It really does help with the drying process:yes:, I think it causes the moister to evaporate faster from the mud. thats my guess why.

And cazna, yes AP and HM do keep shrinking over time, but so does the drywall and wood. What I don't get is guys saying oh hotmud or mesh/paper tape stronger, so my work won't crack blah blah blah.....Bull sh1t
I don't hear framers saying their studs never wrap, or concrete guys saying their foundations never crack. But tapers yak like as if their pissing work is holding the house together:furious:.......NUTZ


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## SlimPickins (Aug 10, 2010)

2buckcanuck said:


> What I don't get is guys saying oh hotmud or mesh/paper tape stronger, so my work won't crack blah blah blah.....Bull sh1t
> I don't hear framers saying their studs never wrap, or concrete guys saying their foundations never crack. But tapers yak like as if their pissing work is holding the house together:furious:.......NUTZ


When I defend my methods against cracking, I'm usually responding to the "mesh tape cracks....period" crowd. I'd never be so brash to claim that my method won't ever crack, that would be ridiculous....houses move, and there aren't many materials that can withstand the forces involved. But, you can defend against folks who think that every joint will get a hairline crack if you use mesh (improperly).

Speaking of cracks, I had my first call-back the other day. I was so bummed out...I went over to check it out and the edge of the bead was cracked, and a couple inches away there was a wavy line that looked like a sine function. (this was a drywall to plaster transition near a tub). So, I masked the area and started digging in....holy moisture. The mud was full of water....turns out there's a failure in the tub seal. I think I would be safe in saying "yeah...this one's not my fault":thumbsup:

I use glass and set muds for seams, paper and taping mud for angles (I like to avoid set muds for angles but will do if needed), AP for skim, and light topping for T/U if needed (then I can sand the t/u without getting the layering typical of light topping over light topping). My top coat is my pre-fill and I'll tell you why....I believe that if you work your set mud into the gap a little, and then coat as normal, you've created a near monolithic structure with your mud....One continuous blob of mud that runs into the crack (and hopefully has some grab on the backside too...like lath and plaster) and has a comparatively deep face that adds support.

Now, when I get on much bigger jobs than I am used to, it's set mud pre-fill and paper on everything. I guess size DOES matter after all


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## cazna (Mar 28, 2010)

Thanks for the replys guy, So Air so far seems to dominate, It would be good to hear from Final touch drywall, I have to admit hes interesting with his methods but he prob cant be bothered with the throw backs we might give him, Yes im guilty of that. Sorry FTD.

And step up you auzzies, i know your mostly setting mud guys, Why havent you guys embraced Air dry?

Im setting mud flats tape and second coat with fibafuse now, Banjo, its going good, There does not seem to be much extra time needed over the zooka, Yes more clean up but thats fast with banjo, and im not waiting so much for the taping to dry as if it was taping mud, started yesterday, by the end of today all flats will be second coated and all screws first coat, 250sm floor area house 2.4 stud, Only 2 days so a zooka would not be much faster and i know come wens when i zooka the corners with air dy it will run really well over the hotmud flats, No catching of semi dry flats with the angle head.

And the screws are fuller with first coat, Air dry seems to keep shrinking in,
And the setting mud has so far been more economic, Bags seem to go further the boxes or buckets.

Im not looking an argument, And im neither right or wrong, These are just some points to make.

The house i did prevous would have been harder with setting muds as it was raking ceilings mono pitch and the zooka reaches better, It was big so i had more time for the airdry to do its thing so i would still air dry mud that place again.


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## Goodmanatee (Sep 24, 2010)

I use mesh and hotmud for seams and butts (1st coat). First pass do all seams, fill bad bits. Second pass, butts and 2nd fill the bad bits. 
Tip you want your hotmud to go off in 10 mins add some table salt. (for that quick patch)
Screws, hotmud (1st coat). mud (2nd coat).
I pin my bead with mud, coat with hotmud then finish with mud.
Angles taped and finish with mud.
Then 2 coats of mud on the joints. (10",12")
Never leave any hotmud to be sanded all covered with mud.
We don't with the same choice off mud over here. I guess what we use is all purpose. We don't have taping mud, green top,blue top. nothing like that.
Hotmud for base coat, wouldn't want it for the finish.


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## gazman (Apr 29, 2011)

Hot mud is the prefered system here in Au. We dont have any taping mud from the three main manufacturers. They all make a AP but I would not trust them for taping.
We prefill where needed with cornice cement which is a hot mud that can be accelerated by mixing, we usualy mix up some in a dish take out some of the mud mix it on your hawk as you are filling and it goes offin 5 min while the stuff in the dish is still fresh so you just repeat the until filled.

Taping is done with base 45, 60 or 90 (hot mud) with either a banjo or Apla zooka (It is time to run)
Second coat depends on the weather conditions. When warm sept - April AP. During the cooler months base is prefered. Unless you can leave it to dry over the weekend. Builders dont supply heat.
Topping is done with with AP or a Topcoat which is sanded.
Builders are not prepared to pay for a level 5 so that does not happed.
There is no texture everything is flat and painted.
We also use cornice on 99% of jobs which is installed with cornice cement. (dont mix to much as it will go off like a bucket of prawns / shrimp in the sun) DIY guys get themselves in a world of trouble with this stuff. But when you know what you are doing it is the bomb.
I think the main reason base is the prefered option here is .
1. The quality of it is very good as that is what the market dictates.
2. The drying conditions (no heat in the cooler times)
2. Our AP is not strong enough to tape with.
So I think if we swaped the mud / base that is available we would probably use each others system. It comes down to availability.


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## Kiwiman (Jun 14, 2008)

I tried some taping mud through the bazooka on a couple of houses recently, good stuff to use but maaaan does it shrink. I've always used hot mud for taping all year round (not through the bazooka) except for the times I've experimented with A/P's or taping mud etc If hot mud or A/P is going to last 30 - 50 years then use whatever suits your style, most homes seem to be redecorated or renovated after 15 years around here anyway.
I also did a new relocateable house recently, I used Fibafuse and hot mud for taping the flats followed by 2 coats A/P, and used A/P for taping and finishing corners, and installed 55mm gibcove (crown moulding), the house is getting moved in a few weeks and I'll be there to inspect it....I'll post the results, it should be interesting to see how it copes.


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## 2buckcanuck (Jul 9, 2010)

Has anybody ever checked out the warning label on a bag of Hotmud, the one we use a lot is sheet rock 90 made by cgc. and cgc is basically USG. It has this symbol on it








*CLASS D: POISONOUS AND INFECTIOUS MATERIAL
Division 2: Materials Causing Other Toxic EFFECTS*
These materials can cause life-threatening and serious long-term health problems as well as less severe but immediate reactions in a person who is repeatedly exposed to small amounts. ​


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## gazman (Apr 29, 2011)

2buckcanuck said:


> Has anybody ever checked out the warning label on a bag of Hotmud, the one we use a lot is sheet rock 90 made by cgc. and cgc is basically USG. It has this symbol on it
> 
> 
> 
> ...


Never seen that on any of our hot mud. Anyway dont believe everything you read mostly they are just covering there but.


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## JustMe (Apr 17, 2009)

*What is a Class D - Poisonous and Infectious materials?*Class D materials are those which can cause harm to your body. They are divided into three major divisions.
*Division 1: Materials Causing Immediate and Serious Toxic Effects*







​These are materials that are very poisonous and immediately dangerous to life and health. Serious health effects such as burns, loss of consciousness, coma or death within just minutes or hours after exposure are grouped in this category. Most D-1 materials will also cause longer term effects as well (those effects that are not noticed for months or years). Examples of some D-1 materials include carbon monoxide, sodium cyanide, sulphuric acid, toluene-2,4-diisocyanate (TDI), and acrylonitrile. The symbol for Class D - Division 1 (D-1) is a skull and crossed bones inside a circle.

*
Division 2: Materials Causing Other Toxic Effects*







​These materials are poisonous as well. Their effects are not always quick, or if the effects are immediate but they are only temporary. The materials that do not have immediate effects, however, may still have very serious consequences such as cancer, allergies, reproductive problems or harm to the baby, changes to your genes, or irritation / sensitization which have resulted from small exposures over a long period of time (chronic effects).
Division 2 of Class D has two subclasses called D2A (very toxic) and D2B (toxic). While it is not a legal requirement for the WHMIS sub-classification to be reported on the Material Safety Data Sheet (MSDS) nor is it a requirement for classes D2A or D2B to be distinguished on the label, it is often possible to make this distinction using the health hazard information on the label and/or the MSDS.
Products are typically classified as D2A (very toxic) if the chemical has been shown to be carcinogenic, embryo toxic, teratogenic, mutagenic (to reproductive cells), reproductive toxic, sensitizer (to respiratory tract) or chronic (long-term) toxicity (at low doses). Subdivision D2B (toxic) covers mutagenic (to non-reproductive cells), sensitization of the skin, skin or eye irritation, as well as chronic toxic effects.
Examples include: asbestos fibres, mercury, acetone, benzene, quartz silica (crystalline), lead and cadmium. The symbol for materials causing other toxic effects looks like a "T" with an exclamation point "!" at the bottom inside a circle.


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## SlimPickins (Aug 10, 2010)

2buckcanuck said:


> Has anybody ever checked out the warning label on a bag of Hotmud, the one we use a lot is sheet rock 90 made by cgc. and cgc is basically USG. It has this symbol on it
> 
> 
> 
> ...


I'm guessing, and it's just a guess, that up there in Pinko Land with your Universal Health Care that there's a little more truth in labeling. I think our muds have a label, in very small writing that says something like "this product has been found to be carcinogenic by the state of California"


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## Cratter (Sep 6, 2010)

SlimPickins said:


> I'm guessing, and it's just a guess, that up there in Pinko Land with your Universal Health Care that there's a little more truth in labeling. I think our muds have a label, in very small writing that says something like "this product has been found to be carcinogenic by the state of California"


I always joke good thing I don't live in California.


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