How to 'Weld' Aluminum Without a Welder

Brazing aluminum with a propane torch and brazing rods.

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[Pyroswmr]

Just a note, when brazing, the filler rod will always flow towards the heat. Had you clamped your setup vertically and gotten the joint a fair bit hotter, you could have drawn the molten filler towards the torch. could make for a significant;y stronger joint.

[captainKedger]

This process will not work outside in breezy conditions. Aluminum cools very quickly and melts at a relatively low temperature. For better results work on a ceramic topped table with a ceramic tile behind the metal you're working. Try to place ceramic on the sides also. This will reflect a good portion of heat which will otherwise dissipate very quickly.

[bkhalterman]

I’m not a welder, I’m a mechanical engineer. It really depends on the application, regarding the weld strength. Everything has an allowable stress; In the case of a full penetration weld, of course it is stronger than what is shown in the video. As an example, if I wanted to make anything that is structural, meaning to AISC standards, the soldering methods in this video would be a death trap. But if I am making an aluminum picture frame, the aforementioned would be a great bonding technique. No sense in attacking this guy, he’s done nothing wrong here IMO.

[DaTwistedOne]

I used to work for a company that Brazed fuel lines for International trucks. The sweeping of the brazing rod across the joint isn't necessary. Once you get used to it you'll be able to tell exactly when the metal is the right temp and you just take the brazing rod and set it in the center of the joint and it will flow on its own leaving a perfect seam.

[malochala]

Good video. I like your method.

As a maintenance technician, I have also used these (only when necessary!) in an industrial environment. I would advise against using these in any situation where high strength is needed. Only use these when you need a very light duty, low stress joint. They don't hold up well to vibration or in a load bearing capacity. Additionally, don't use them to stop leaks in aluminum tanks where you have a lot of water pressure. They don't hold up to that very well either.

[Leftism]

FLUX IS THE KEY...

After seeing your video, I bought a MAP torch and the same Bernzomatic brazing rods you used. But no matter how well I cleaned and prepped the aluminum, I found the strength of the brazing disappointing. The 'solder' just didn't adhere very well to the aluminum.

I then watched the YT video by Vulcan Systems showing their "G-51" flux + brazing rod demo. So I purchased their product to try it and compare. I just got it today, and as my control test, I used their powder flux with the Bernzomatic rods.

HUGE difference. I cannot rip the two pieces apart with a vice and pliers. It's just like in their video--extremely strong--effectively like a weld.

Besides the obvious benefit of producing much better adhesion, the flux is nice because it changes from powder to paste, then to liquid when the aluminum gets to the right temp. No need to guess whether its hot enough.

Also, the flux helps to produce the capillary action they show in their video--the solder just flows into the joint, whereas without flux, the solder seems to just sit on the surface or edges only.

I highly recommend picking up some aluminum brazing flux if you do any more Al brazing. The improvement is incredible.

Based on the quick shopping I did, the Vulcan G-51 flux + rod kit was a pretty good price--certainly much cheaper than the two rod package sold at Home Depot.

[ferrumignis]

These brazing rods actually work pretty well once you learn the right technique, it makes a surprisingly strong joint. Really useful for repairing alloy castings like the side covers on bike engines.

[spacial]

That was excellent. Thank you for getting straight to the point. Clear and informative.

[franklinprichard]

As a plumber this really excites me...the possibilities.

[invictusbpprop]

Use the smallest clamps and as far from the weld as you can. Aluminum transfers heat quickly so youll be heating your clamp to surface of the sun levels while the work is still too cool. This is particularly important when brazing a second joint next to or very near an existing braze. If you have clamps pulling heat off your joint it can pull it thru the other joint already done and cause it to hit temp before you're ready inn the part you re working on and next thing you know, you have aluminum dripping out of the other joint and it all falls apart in front of you. The temp needs to be just right...not too hot to release other work abd not so cool it takes forever and doesn't flow. If it looks ugly, heat it up again and get it to flow. You can even use w small screwdriver or something to swipe thru the puddle to get it to lay right. But don't get crazy. And dont keep pushing stick into the weld and make a big mess of it either. It doesn't take much. And remember the stick melts quicker than any material youve already laid down and If you melt stick into an existing welding will melt right away. Heat the work to tye point it will melt the stick and it will pull it into the joint. Don't just blast the stick with the torch because it won't flow into the joint and the work wont be hot enough to make it stick as good as it can.
Biggest thing to remember is to keep clamps away from the joint if possible and if your work can be clamped to something to support it with the clamp being 6-10" away, you're golden. All your heat will stay where you want it. Anything the work is sitting on or touching it within 6-10" is sinking heat from the work.

[nhjonesy]

6 years later and your video was still super useful - I didn't know I could do that! Thanks for sharing.

[chipmunkninjah]

I've always wanted to get into metal sculpting for making art, but it's always been too expensive to get a welding machine. This method allows me to try out sculpting in metal without too much of a "start up cost". Thank you for this! :)

[jcThib]

This is an awesome tip, David! I had no idea that aluminum could be welded without an expensive AC Tig welder. Definitely going to use more aluminum in my projects. Thanks to people like you, sharing free knowledge, humanity is less dumb every day :)

[AwakenedOnes]

thank you for this video and tips! I'm a diy queen 👸and this year the skill I wanted to add was beginner welding and this method will work perfectly for my tiny home conversion build where I'll use this method to repair furnace removal in the aluminum siding of my vintage rv and patch it! I'll also build a aluminum frame to house my generator I'm test the strength of course before using!😊

[koitorob]

I'd suggest using a good flux to ensure you get rid of the aluminium oxide on the metal surface and filing a bigger bevel on the tube ends to get more filler rod in the joint.

[paulmoffat]

I made a small tool to help in making a clean and strong joint in aluminum; I used a 1/8" Stainless Steel rod, flattened at one end like a screwdriver, and inset into a wood down for a handle. When the joint is initially formed, I use this took to scrape the base aluminum to remove any oxide layer, and to merge the brazing rod deeper into it. I can also use the tool to draw out the fillet and make a nice clean bond. Keeping the torch on the joint helps in the operation. One thing to remember - the brazing rod is a Zinc-Aluminum alloy and does NOT wick into the joint like a 'solder'.

[cadenceandfamily]

Amazing! Thiers nothing better than an honest instruction video! So far this seems like the most straight forward video. Nothing worse than buying a bunch of junk because thiers videos that make you feel you can't go without. I will try this method and see how this works!

[toolify]

This is awesome – being able to work with aluminum like this opens up so many possibilities!

[MrAabbccddeeffgg]

Interesting. A great solution for those of us who want to make aluminium artefacts but who also have a life which does not involve obsessing about becoming an expert on TIG or MIG, whatever their benefits to ones ego might be. Thank you.

[michaelt.]

This proces is not exactly brazing, the rods used are from a firm called Technoweld. The process is actually more than just brazing, there is a chemical reaction between the welding material used and the alloy. If done correct the joint is pretty strong.
If you want to make the joint even stronger than the weld demonstrated here you can scrape the weld with a thin stainless steel needle, this will mix the alloy and the welding rod even better, making the chemical reaction work better. Personally I have made welds using these materials which proved to be very strong indeed. But no they are no math to the real thing hens MIG and TIG welding. Never the less, when done properly the weld is really strong, not to be confused to soldering.
Brazing materials can in some cases prove to be stronger than welding, because less heat is used thus avoiding stresses and crystallization.