What happens if I *heat gun* joing compo
chefwong
| Posted in General Discussion on
I was testing this spot where I had to make a patch and had just bucket Joint Conpound. Used a heat gun, etc and the top skin dry. If I tap on it, I know the inside is still wet….
Because the top is skinned hard….will it take longer for the *inside* to dry or just as long as if I had not taken a heat gun……
I’ve got wood flooring guys coming in on Thursday and need to prime/paint before then.
Or do I just knock it all down, and go out and buy some spackle….
Replies
Use Durabond it comes in a powder that you mix with water. It dries in 1/2 an hour to an hour.
I think the heat gun stuff is going to crack.
What's wrong with me? I could ask you the exact same thing.
Man, we used 20 minute setting mud (Durabond) and it wasn't dry at the end of the day! I had to wait until the next day to paint it! Maybe it was the humidity, but I always thought it set through a chemical reaction that got faster when it was hotter and didn't have anything to do with humidity. Anyway, my recent experience with Durabond certainly destroyed my faith in its setting rapidly!
I think Stilletto meant that it was hard in a half hour not dry. durabond is a setting compound and hardens not by drying but by crystallization, a molecular change if you will, like plaster of paris. It hardens before it dries,.
"Man, we used 20 minute setting mud (Durabond) and it wasn't dry at the end of the day! I had to wait until the next day to paint it! Maybe it was the humidity, but I always thought it set through a chemical reaction that got faster when it was hotter and didn't have anything to do with humidity. Anyway, my recent experience with Durabond certainly destroyed my faith in its setting rapidly!"You mentioned too completely different things.SettingDrying.It should have been set after the 20 minutes, more or less. That is it is HARD.But it an still be wet and if you try to sand it the wetness will allow it to clump and gum up the sandpaper.
If I need to quick dry mud, I use either a fan or a dehumidifer. Think about it. Its not heat that allows the mud to dry, the mud needs to release its moisture and its easier for it to do that in a dry room. The fan will circulate the air helping to move the moisture and the dehumidifier will just plain eliminate the moisture.
Try it.
it'll probably alligator on you
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We have forced "all purpose" green top USG dry with a heat gun for years with no consequence. This is especially handy in small repairs.
With a large area it isn't practical - takes too long. Use fans.
Don't use a heat gun on the taping coat with paper tape - pretty good chance of "dry tape". It's ok on fiberglas tape.
We don't get it too hot. We heat it then turn it on cold - back and forth.
I don't see the advantage of using the "setting muds". You can't do anything until the water is out of them anyway, so what's the advantage? Plus I wouldn't be confident about the next coat sticking good if the "setting mud" wasn't dry.
"I don't see the advantage of using the "setting muds". "
It gives you the opportunity to double coat within the hour. If you know how to float and sponge, you can do a repair with p.o.p. and j.c. and be totally done with the job in one shot, no sanding involved at all. And yes, you have to wait for it to dry. This is actually plastering.
I do plaster repairs in my sleep.
If it's a small repair we use fiberglas tape, all purpose, force it dry with heat gun and a fan present too, sponge or lightly sand with heat gun pulled away "per stroke", stop heat gun long enough to make sure it is dry - prime with kilz or usg "first coat", and bam bam bam - we can apply finish coat. It looks good even under a bare bulb. We sand or sponge with a bare bulb.Obviously you wouldn't do all this in most situations. But for the situation that it fits, know that we have tried and proved that this works with no consequence. (I am assuming everyone realizes that you can't have a "deep fill" here where mud is going back in and will hold water which will come to the surface later)(edit) I keep forgetting to mention that for some reason the heat gun doesn't seem to work at all on "light weight" muds. They seem to have an "insulating quality". We don't use them any more - or setting muds.
Edited 8/1/2006 8:28 am ET by Fonzie
As you said most situations dont require a heat gun or IMO hot mud on repairs.
I think this poster has more time than that too. A high speed fan will get reg mud dry in a couple hours while you are working on somthing else . [if its not a deep fill like metal]
Time has always got to be figgured in dealing with hot mud mixing and cleaning up.
You can pop the lid on a bucket of mud and do the coats at leisure . Ive even put the pan of mud in a walmart bag if not in a bucket of water and Im doing somthing else with no time lost.
Of course that doesnt work if you are only there to do a repair . Still it takes more rigging and unrigging time than the work itself.
You are right in situations are different .
If Im taping a room at 3 pm and going home . I dont need to mess with hot mud if my fan is handy.
Tim
Those little expensive fans that tilt ? They do a nice job in an hour or two on a big patch.
Durabond is good for setting tape and filling . They make it in different minute times . If you want to speed it up add hot water .
To answer Fonsie , no the water will be in it still and will look "green or wet" . But as long as its firm you can cover it with anything and it will dry before the top coat . You dont want to screw up here and put durabond over wet joint mud.
They also make Quick Sand which is really a timed finish topping mud. USG brand . It wont bleed through paint like durabond . So yes Durabond must be covered and not used as a top coat . Adding hot water to it does the same thing .
Using fans in any application will quicken the process .
Ive used a heat gun to set durabond and it has never cracked although joint compound would on a heavy fill .
Tape helps wick out the moisture quickly with reg joint compond .
Tim
reason I say it will alligator is with his description of tapping and feeling it dry on top and wet under neath makes it sound like he has it too thick and trying to do whole job in one coat.
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And it probably would .
It still has to dry sometime but I dont like the heat gun method on a heavy fill. Since it was reg mud it wasnt helping anything to dry the top of it off first as you say. I really dont mind the alligatoring if it will just dry so I can recoat it . Metal does that a lot on deep fills if its not side taped . Its just part of it .
Tim
The dry mix doesn't shrink as much as the bucket mix, especially if the patch is heavy and thick.
If you put it on thinner, it dries a lot faster and you can do three coats in a day, more if you put a fan on it. For small patches, they make 20 and 45 minute setting time and if you want to make it seet faster, use hot water but be prepared to work fast.