Hot Mud MAY FAIL if You Make This Mistake.  That Kilted Guy Drywall School

Hey, did you know that if you use the fast-setting joint compound or hot mud as we call it, that a lot of you are using it wrong and you could be causing failures? I'm going to tell you why right after this. Okay, this is not clickbait or something. This is something that a lot of you probably don't know. I kind of knew this, but I recently read it a few years ago and confirmed it. And that is that if you use hot mud, you have to put it on a certain thickness. But first, let me tell you why you might want to use fast-setting joint compound if you don't already. It's a fantastic product if you know how to use it. But if you don't know how to get it on nice and flat the first time, you probably don't want to use this. You've got to be real careful because it is really hard to sand, despite the fact that the bag says easy sand. That just means it's easier to sand than a rock. I mean, that's about how it is. It sands, but it's really hard to sand. So you've got to put it on nice and flat. But the advantage is, it's a setting type mud. It doesn't dry much faster. It does dry a little bit faster because the fast-setting joint compound, the way it works is through an exothermic reaction, it's a chemical reaction, and it generates heat. That heat will cause it to dry a little bit faster, but mainly, the advantage is it sets up quicker. So, let's say you use a 20-minute hot mud. There's like 5-minute, 20, 45, so on. If you use a 20-minute hot mud, that generally means you have 20 minutes of working time. And in about 30 minutes after you've mixed it up, you'll better come back and put another coat of mud on it. It doesn't have to be dry. Just set up. When it sets up, it is firm. The reason that works is because normally, with regular joint compound, if you just let it dry a little bit, you haven't allowed it to finish shrinking. Regular joint compound shrinks a lot more than hot mud. So when hot mud sets up, it quits shrinking. It's locked in place, so it has very little shrinkage. Now let me show you. I put together these little molds a while back, and I put different ones in different... I made a number of different molds, so this was all-purpose. And it says I put mesh in here, but I can't see it. But that's not really the point today. The point is, this one was hot mud. Let me get a little bit closer for you. And this is all-purpose. Now, do you notice all the cracking and shrinkage? If you look at it, I don't know if you can tell on camera, but it shrunk in there a pretty good amount. Now, usually, it likes to focus on me, so hopefully you can see that gap under there. That has shrunk quite a bit. This has almost zero shrinkage. And it's much tougher. I could probably hit this quite a bit harder, but I don't want to break it because I got uses for it. This one, I've tried taking it out of the mold, and it just falls apart. It's way weaker. It shrinks a lot more. It takes forever to dry when you put it in here this thick. That took like a week to dry. So when you're going to put hot mud on any thicker than an eighth inch or so, butt joints, repairs, things like that, this wins every time because of that low shrinkage and that quick recoating time. That's the main reason we use it. If you're going to use mesh tape, you have to use hot mud with mesh tape on the first coat. So it's a great product, but if you don't know how to put it on flat and you put it on a little too heavy, you're going to sand your life away, so be careful with that. But here's where a lot of you are making a mistake. Now this is from the manufacturer. They say that this has to go on thick enough so that it sets up before it dries. So if you're putting on a thin, skim type coat, whatever it is, over joint tape that you've already coated a few times and you put on a thin coat with the hot mud, it may not be adhering well because it requires that chemical activation in order to get the bonding strength. It won't bond well if it doesn't cure. So if it air dries, it hasn't had time to chemically activate and it just doesn't have as good a bond. So I would stick to, if you watch a lot of my videos, you'll see on the last coat when I'm doing a repair, I do hot mud and hot mud and then I break out like plus three for the last coat because I've always done that. So I always kind of knew that you need to put it on with just regular joint compound on that last coat. If you put a fan on it, you'll get it done just pretty much the same time as if you try to use hot mud. So just be careful with that. Use hot mud for everything but that final coat. Never skim coat walls with it, joints. Don't even spot your screws and nails with it because it goes on too thin, at least after the first coat. You might get by with the first coat, but after that, you're putting it on too thin. Use regular joint compound. It'll save you potential failure. Oh, and hey, I'm going to be putting out a video soon with about something like 10 or 15 tips about hot mud that most of you, there'll be some of those tips you don't know. You may not know a lot of them. There's a lot of secrets to hot mud that'll help you out. Be watching for that video coming out sometime soon. And hey, if that video helped you out, here's another one right here. Check that one out and I'll see you on the next video. Take care, everybody.