How to Bend Metal Rods Using Heat
George VondriskaDescription
Yeah, we use our shops (primarily) for woodworking, but most of us have other things going on in our shops too. In my case, I recently had to bend some metal rod for a shaving horse project. Do you want to know how to bend metal? We’ve got you covered. Let’s turn up the heat on this topic.
The Setup
Don’t put that chunk of soon-to-be-hot metal in a vise with wooden jaws. Your best bet is a metal vise. Even though we’re going to be heating an area well away from the vise, the entire rod is going to get pretty warm.
Your vise can act as a HUGE heat sink, so keep the spot you’ll be torching as far from the vise as is practical. If you don’t the heat you’re applying to the rod you’re trying to bend will migrate to the vise, and you’ll waste a lot of gas heating stuff you don’t need to heat.
Flamin’
When you want to bend metal, you’ve got to get it hot. Red hot. Like a chili pepper. The best way to do this is with a torch, available at home centers or online. (I love the self-igniting kind) You can use a propane tank or MAP gas to fuel the torch. MAP will get you to the finish line faster than propane, but they’ll both get the job done.
Expanding your Repertoire
Now that you know how to bend metal, you can look for cool ways to incorporate this skill into your upcoming woodworking project.
Projects for You
You like to stay busy in the shop, and we like to keep you busy with woodworking project ideas and helpful shop tips. Have a look, you’ll like what you see.
Yeah, we're in a woodworking shop. However, sometimes you run into occasions where we gotta do a little metalworking. And that's what I wanna look at here. On this shaving horse I built, it called for a metal pin that acts as a retainer here. And it needed to be bent into an L in order to hold that board in place.
And then give us something to grab onto when we wanna remove it. So I learned a couple things when I did this. And I'm gonna pass this along to you. One, let's talk about gas selection. If you go to a big-box store or a hardware store.
Blue is propane, yellow is MAPP. So for years, in my shop. You know, I've done plenty of soldering in home improvement projects. And I always use propane for that. And then when I started poking around a little bit about.
I have seen these things. What's the deal? The MAPP gas burns hotter. It's a little bit more expensive than propane. But what it's gonna come down to is that because it gives us more heat, it's gonna get us to a point where we can bend metal quicker.
So I switched to the MAPP gas and it made a big difference. The same tip is compatible with both bottles. So there's no change there. So MAPP gas is a good way to go. Then too, when this half-inch metal rod goes in the vise, one of the things you wanna be cognizant of.
Is that we're gonna heat this out here. We're gonna do an L bend, just like I showed you. And if that bend point is too close to the vise, what's gonna happen is, we're gonna take forever to heat this up. Because that vise is acting as a big heat sink. And a lot of that heat is telegraphing to that huge piece of metal.
So that's very intentionally why I have my bend point projected out here, away from the vise. Just another word about metal vises. I love this setup. I don't use a metal vise often. But I use it, obviously.
So what I do with mine, is I put it on a piece of plywood. And then when I need it, I can bring that plywood to my bench. Clamp it in place. And I've got access to my metal vise. We definitely don't wanna have this in the wood jaws of my good wood vise.
Because of the heat that we're about to generate. Anytime you use a torch, doesn't matter which one it is. The hottest point of that flame is the very, very tip of the blue. So there's a little bit of a tendency to wanna bury that flame. Like that, up against the metal.
But your best bet to get this to heat up quickly. Is to get the tip of that flame on your bend point. In real time, it's been about 10 minutes. And I'm looking for, I want this to be red-hot. Like a chili pepper.
And in the world of stuff we need, the other thing we need is a grabby thing. Don't grab that with your hand. And when I first pull on this, if it's not- Oh, look at how easy that's going. If it's not inclined to go, apply a little more heat. That's perfect.
That's absolutely perfect. So a couple of tips there. In case you run into this in your shop. A MAPP gas. Portable vise, metal vise.
Grippy things. Give it time, let it get good and hot and it'll bend easy. Now another lesson I learned out of this, the hard way. When I went to the hardware store, they had two types of rod there. And the first one I bought, it was called welding rod.
Same deal, half-inch, 36 or 48 inch length. And when I went to heat that, it took forever. There was no way it heated in 10 minutes. And what I later learned is the metallurgy of welding rod is completely different than this stuff. So this silver, big-box store, hardware store rod.
When you're gonna bend it with a MAPP tank. It's definitely the way to go. You can get the welding rod to bend, but it takes a lot more heat and a lot more time. So some tips there to help make good, cool, hot things happen in your shop.
Having a container of water around is a good idea as well if only to dunk the bent rod (which stays very hot for a long time)
I agree with David about heating both sides but rather than getting two torches, simply rotate the torch so that it's heating from one side for about 10 seconds then rotate 180° to the other side for about 10 seconds, then repeat. As far as the "wrinkle" issue, I am not following him but if the metal is properly heated there should not be any wrinkles. BTW, the cones that you see (inner and outer) are actually hollow. If you place a metal window screen over the flame you can see the inner and outer rings of each cone. That's why placing the flame too close to the object is not going to heat it because there's no "there there" when it comes to the flame. Also, in that regard, it's better to be a tad from the point instead of a tad within the point.
Where does one go about obtaining one of those specialty "grippy" tools? I might never need one, but obviously NEED one! That looks like something a regular, run-of-the-mill pair of cheap pliers could never accomplish! Thanks George for introducing us to yet another fantastic tool "only for bending welding rods"!!
This will not play on my new iPhone. It goes to a Panera ad that also doesn’t play.
Why does my screen stay black? I can watch the ad, but when the movie starts, all I get is music and George's voice, but no picture.
Instead of slip joint pliers, try slipping a lengh of conduit or other pipe over the end of the rod. You can get closer to the bend, it doesn't leave tool marks and gives you great leverage.
I have another for holding a metal vice to my work bench I have the ply wood as you do but I also have a piece of 2x2 inch screwed to the bottom. I can clamp it in my wood vice and it means it can’t swivel if side ways pressure is required.
Hi George. Great tips on bending a metal rod. A couple suggestions is to use 2 hand held torches to preheat the metal & it will shorten the preheat time to less than 5 minutes, likely a couple of minutes for a rod that diameter. Also heat the inside of the bend to creat a slight fold of red hot metal as the bend is formed & do not put as much heat on the back side so it remains cooler & does not glow red. This allows the back side to hold its shape & form a wrinkle of red hot metal on the inside. Larger rod or pipe can be bent in 2 or 3 wrinkle bends to avoid over stretching the back side & maintain structural strength on the curve.