Need to stick some metal to metal but don’t have access to a welder? You’re not necessarily out of options. Welding is usually the best way to go, but there might be a few alternatives that could work good enough for you.
In this post, I’ll outline three options, along with their pros and cons:
Ways to bond metal without welding:
- Epoxy
- Riveting/bolting
- Brazing
- Or just get a welder anyway.
Epoxy
This is probably the most popular option for beginners. It’s definitely the easiest and cheapest solution, but it doesn’t always hold up as expected.
This can be a good option for non-structural components, though. If you need to just need something to stick in place, and it doesn’t need to hold any real weight, then this might work just fine.
The Pros
Stupid easy. Mix the two parts of the epoxy, then glob them on the pieces that you want to stick together.
It’s quick and convenient. It’s usually a pretty decent way of doing a temporary fix until you can just buy a welder.
The Cons
Don’t take those “thirty kazillion PSI strength” claims. They usually don’t mean much.
While it can adhere well, the stuff is super brittle. It doesn’t take much to snap it in pieces. Glass is strong too, but it also breaks.
Tips for Epoxy
First off, it won’t properly adhere to all metals. For example, polished aluminum is nearly impossible to bond to.
If you’re bonding metal with epoxy, it’s extremely important that you thoroughly clean the surface of the metal. If the metal is smooth, it probably won’t stick very well. At the very least, scuff it up with an abrasive pad or some sandpaper.
Alternatively, you could etch the metal surface. This will give a nice, bumpy surface that the epoxy can really bite into. If you haven’t already, check out my article on saltwater etching. It’s stupidly easy, and you probably already have everything you need to do it. It’ll give the epoxy lots of surface area to hold on to.
The hands-down #1 mistake that people make when using epoxy is to not properly prepare the surfaces. Make sure they’re dead clean and oil free. Ideally, use a metal prep to get adhesion.
In terms of epoxy, make sure you’re using the right stuff. Lots of the “general purpose” stuff out there just doesn’t work that great on metal, despite what the label might say.
If you’re trying to bond metal that won’t get hot, this is the epoxy I recommend. For metals that will hit higher temperatures, this is the one to look at.
Riveting or Bolting
This is a definite step up from epoxy if you’re able to do it. Rivets or bolts won’t snap (hopefully) and can take significantly more abuse. Having a mechanical connection will nearly always be stronger than simply gluing something together.
The Pros
This can totally be a permanent fix. Pop riveting is actually pretty easy to do, and the tools are cheap. Bolting has the advantage of being optionally non-permanent. You can always take it apart later.
The Cons
It’s not always practical. For example, pop riveting tubes together is very straightforward. Even if you can do it, you might not like the results. And riveting is pretty well just for sheet metal.
Bolting can possibly be a bit more versatile, but you’ll also have to install either a nut or put threads on one of the pieces of metal. It’s basically just more work.
Either way, you’ll need to drill some holes and line things up.
Tips for Riveting and Bolting
Pop riveting is by definitely the easiest kind to use. The tools are cheap and it’s quick and easy. Here’s the setup I recommend.
Bolting is straightforward. Just pick up what you need from the hardware store, and talk to a team member if you’re unsure of something. There are lots of types of screws and bolts for different applications, so just explain what you’re trying to do.
If you want something that’s a hybrid of the two and really cool, try out a rivet nut inserter. It installs a nut in a piece of metal using the same principles of a pop riveting gun (squeeze the handles and the nut expands until it’s firmly stuck in the metal) and the result is a threaded hole that will accommodate a machine screw. It’s very strong and it’s extremely popular for automotive repair/modifications.
Here’s a video that’ll show you how this works:
Brazing
This can be a lower cost option in terms of setup. It’s a solid way of joining pipes together, too. For brazing, you use a flame torch to heat up the two pieces of metal with a flux to protect it from corroding. Then you use a braze (a dissimilar metal with a lower melting point) to solidly stick the two pieces together.
The result is basically a really solid metal “glue” that can take a lot of abuse.
The Pros
It’s very strong, it’s not that hard once you get the hang of it, and it works extremely well for joining pipes. This is what plumbers use to join copper pipes, and they last for decades under high pressure.
This can work especially well for nonferrous metals like copper.
The Cons
It does take a bit of practice, and the material needs to overlap to be effective. It’s not a good solution for metal that needs to be joined end to end (for example, two tubes that don’t fit one inside the other).
It also doesn’t work great for all metals, and some need a pretty powerful (and more expensive) torch. For brazing iron and steel, you’ll usually need an oxyacetylene torch, which will set you back a few hundred bucks for a beginner kit.
Tips for Brazing
Watch a few videos to see how to properly clean the surface of the material and ” wet” the areas to be joined. Make sure that your torch and braze is appropriate for the metal that you’re working with.
Here’s my recommendation for a torch kit that’ll cover you for the large majority of applications.
For smaller projects, or for simply joining copper tubes, get this torch and this fuel.
Are You Sure You Can’t Weld?
Honestly, welding is usually the best solution, especially for joining steel to steel. A beginner’s welding machine that will get the job is surprisingly cheap (although, of course, everything is relative).
If you want to just take a peek at what you could get for a small, inexpensive welding machine, check out this one on Amazon. It’s really cheap, and an absolute beginner’s kit, but you’ll be up and running pretty well instantly. I’ve had a similar model for several years for the occasional project, and it’s worked just fine.
All of these solutions are a heck of a lot better than duct tape and gum, but each application has a different solution. If there’s one option that stick out to you, do a little extra research to see if anyone’s using that method in a similar way.