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Quick and easy brazing aluminum, copper and nonferrous metals

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Brazing is a quick and inexpensive alternative to welding. The equipment in this project can be bought for as little as $30 dollars. Brazing is also much easier then welding, it's a lot like using a glue gun. Brazed metal can also be stronger then welds. And for personal projects and small production runs, brazing is much more cost effective.

In this instructable I'll show you how to fix a bicycle kickstand, make bi-metal candle sticks, show you a few examples of other things you can make. There's a lot more you can do, this is really easy and I hope this will get you started.

I think many instructable projects on this site could be simplified with this technique. Basically, with any project where you want to make something strong out of metal like aluminum or copper. A couple ways you might use this include mechanical uses like adding a foot to a bicycle kick stand, making a bicycle cart or part on a lawnmower, and uses in electronics like soldering copper to aluminum to a solar panel backing. Brazing is just great for a lot of things!

Brazing, means melting an alloy to join two metals. There are a few different brazing systems out there. My favorite is low temperature brazing using an alloy called HTS-735-II. It brazes at low temperatures and makes it easy to connect all sorts of metals and the welds aren't brittle.

Project Materials:
* Propane torch
* Low temp fluxless brazing rods (These are hard to find so I listed a couple places people can get them.)
 - Alumiweld 730 rods from Harbor Freight Item #44810, they cost about $14 bucks for an 8 pack.  To braze a kick stand you might use 1/4 a rod. 
 - You can buy pounds for around $35 a pound from alumiweld.com this is where Harbor Freight orders from.
  - Or HTS-735-II welding rods  can be ordered from these companies in US and a UK seller. These companies charge around $70 for a pack, so it's not the best deal though this is what I used in my projects.
* Pliers
* Protective Gloves
* File or steel wool to clean the joint surfaces.
* A brick or steel can or tray to braze on.
* Metal pieces you want to connect together like: aluminum, magnesium, zinc, brass, copper...

Note:
* Not for food grade applications.  Having called the manufacturer of  the Alumiweld product, they said they are not selling a food safe product yet, though they will be. So I'll update this instructable when they do. But with the current product I wouldn't let the product have prolonged contact with skin or food since I don't think it's designed for that.

If you do want to join pipes for food applications here is an easy to use product for that purpose:
#450 Soft Silver Solder
96.5% Tin / 3.5% Silver
Melting Point: 430° F
"Use: Ideal for electrical work, utensils, and dairy and food equipment."
http://www.aladdin3in1.com/catalog5.htm

FAQs:
* There are two methods I use for welds, melt and blob methods. Both are described in their own section.
* I use the term "welded" instead "brazed" a lot for a few reasons. First it's common language and people who are starting out with this will be confused by technobabble. The Second, I use the term "welded" because that's how the product I use describes itself.
* This is low temperature so there aren't a lot of fumes or uv light dangers. I often use this indoors, though a garage with good ventilation is probably recommended.
* The weld point tends to be stronger then the base metal, if the metal is aluminum or copper. So you can fill in gaps like dents in propellers and holes or cracks.
* The alloy I'm using here can be used at sea, it won't disintegrate from electrical differences. So you can fix propellers and things with this.
* Making an odd sized nut. Because this alloy does not stick to iron or steel screws, you can melt it onto an aluminum or brass washer and build it up around the threads. Then give it a twist with a wrench, it comes free and you have a nut.
* Making bushings or custom threaded screw holes. This is also usually hard to do. But if you have a piece of steel you can put in a hole and you fill around the hole with this stuff, this alloy won't stick to the steel so when you take out the screw you had in the hole you will have a  it will make a threaded screw hole. If you used a smooth steel bolt then you will have a close fitting bushing.  Though the hole will be tight so you may need to sand it if you want to use it as a bushing.
* FYI I don't sell this welding product and I'm not associated with the companies that do. This technique is just cheap, easy and awesome! Enjoy!
 
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gathem1 year ago
I have tried some brazing, but I always ran into one major issue... warping.
Every time I heat aluminum with a torch it warps terribly. Most of the time I am working with 1/8 L stock or 1/8 plate stock.

Any tips for avoiding this?
steam_cannon (author)  gathem1 year ago
Hmm, I think I know what you mean. Most of what I've done has been with rod stock and not plate stock. With rod stock, I'd suggest wafting your torch over the aluminum and testing the temperature with the brazing rod. I often wave the flame back and forth "a lot" over the whole piece so I don't overheat the aluminum and wave the flame over the whole surface area as much as possible. I was doing that kind of by instinct, but that's how I avoid that problem.For your plate stock problem, another way might be to put the piece into an enclosure and heat the enclosure slowly. When I make a ceramic cup in a bbq grill, I put the cup in a closed metal container so drafts don't warp and break the piece. Along that line of thinking, perhaps heating the plate in a kiln or oven might help reduce the heat difference causing your warping problem. Once the piece is heated, then finishing the brazing process with the preheated metal.
Brazing rods are also Called Soldering rod consist of fine metal ingredients. These Brazing rods are used for the special purpose of hard soldering, welding and brazing. These brazing rods are highly durable and reliable as it is made up of strong alloys.
Kevanf13 years ago
Any idea what these rods are known as in the UK? I have tried both an eBay search and looking them up on Google but didn't find anything. eBay came up with zero :)

Excellent 'ible' though, this will come in very useful for aluminium work I have to do.

Kevan
Dr Qui Kevanf13 years ago
Durafix easy weld is what you are after.

eBay has the best price by far, sadly i found this out after i had bought from the official dealer
steam_cannon (author)  Dr Qui3 years ago
The prices on eBay aren't bad. :)
Yeah, I've found this too. I haven't bought any yet as I'm not ready to do the repair (part of the aluminium bodywork on my 40 yr old Land rover) but eBay is something like at least 50% cheaper than buying from elsewhere including direct!!! How can that be? However they do it I shall be getting my rods from eBay.

Unless, that is, I can get set up with aluminium welding on my mig welder.... I ought to have done an Instructable about this I suppose as I've just fitted a Euro torch socket to it.
An aluminium bodywork can be repaired (if it's only repairing small holes and dents) with tin-lead and a good flux for aluminium (Harris). Zinc alloy (alumiweld etc) are pretty hard, do crack and sanding can be a pain. Tin-lead if far softer, malleable and won't crack. Plus it melts under 200°C.
steam_cannon (author)  Ilan Voyager2 years ago
That's a good point. I mostly use zinc alloy for structural work. So if you want to do body work then soft and malleable metals like tin-lead would be a better choice.
Tin-lead has been used in body work since ages, with steel, irons and later aluminum. The advent of polyester paste, easy to use by non skilled workers, has made obsolete the use of tin-lead. Unhappily polyester with fillers is not good material for that work as adhesion is very poor and has no resistance to water. For a true job you have the choice between soldering (the old fashioned way) and a good epoxy resin with specialized fillers as we do on yachts and ships.

What do you call structural? I would not use zinc alloys on structural works where a failure would be catastrophic. The adhesion (if no flux is used) is rather impredictable and zinc itself is a source of worries with galvanic corrosion, specially when in contact with copper or its alloys.

For example on frigorific works tin-silver is preferred. A zinc join would not be reliable because of the possibility of stray currents.
steam_cannon (author)  Ilan Voyager2 years ago
Regarding stray currents and degrading in sea water, that's what I thought too, but I was also wrong. Alumniweld can be used for repairing boat propellers in sea water and other marine applications. So it tends not to have a stray current/battery degradation problem. It's a very stable alloy.

Regarding structural capabilities, it can be used for repairing engine casings which require significant structural strength and vibration resistance. It is used for repairing propellers as well. In my experience working with it, it seems fit for use for structural components such as connecting supportive pipes/bars. Now if it was pure melted zinc, then I would agree that wouldn't work. But the alloy seems to work much better then pure zinc, which I use regularly for metal casting.
There is a difference between claims and reality (I'm a retired naval engineer and worked mainly in warships building, so I have some lights about metallurgy).

Alumiweld (whatever they claim), Aladdin 3, Welco 52 and all that stuff are made basically of an alloy of zinc at 96-97 %, aluminium around 3% and a bit of copper and other metals. This alloy has been known for more than 80 years.
The best proof is all that stuff melt at the same temperature; 490° C, have the same use and solder the same metals. There are no miracles in joining metals.

Whatever the -small- variants in composition it's basically zinc with an electrical potential lower than aluminium. Briefly an anode in case of electro-galvanic corrosion.

The lone true fixing on aluminium propellers and casings is welding mainly with a 4043 or 4047 alloy, but the zinc alloy works in most cases as most of these repairs are not structural (a hole in a casing does not affect its structural integrity, a long crack yes and in this case you have to weld), and are made on not highly stressed small structures.

The great advantage of zinc alloy is the low temp, so it requires a simple torch. The inconveniences are corrosion and sometimes resistance at long term.

The stress performances are not sufficient and reliable enough for structural purposes. By structural I mean a joint able to withstand the stresses, vibration cycles, and corrosion effects of a structure stressed at the maximum possible. You'll never see zinc alloy joints on aluminium boats, planes and even race bicycles.

I almost forgot: 490° C is enough to temper (=soften) heat treatable aluminiums like the 6061. (have you remarked that industrial aluminium ladders are never welded ?)
steam_cannon (author)  Ilan Voyager2 years ago
My experience is this product worked better then expected for many repairs. So you're saying a cracked bike frames and ladders can't be fixed with brazing because it will ruin the temper. Ok. No product can fix everything.

Anyway I've had some great experiences with Alumniweld and I would recommend it for all sorts of projects. Some more great project ideas:
* Building a light metal frame for a robot
* Building a metal frame for a picture
* Build a roof rack
* Make metal green house shelves
* Make an angled plant hanger
* Make metal toy boats
* Build a fishtank or speaker support.
* Fix a lawn mower wheel bearings or bolts
* Build a small engine support

And "yes" it is a miracle to make basic repairs without spending thousands of dollars and hours of training on the equipment.
I do agree totally with you as I use myself zinc alloy to fix on or make objects as you described. I do not see the need to take the TIG on light work when a zinc alloy or a tin-silver will be strong enough and simpler to make with a cheap torch.

All that I wanted to point that zinc alloys cannot be used in stressed structures where a failure could have catastrophic consequences like on a mountain bike, a ladder, or inside an engine. That bothers me to read impossible claims or to see videos of the kind of a guy fixing a crack between the two valves of a car engine...it's simply outside the possibilities of zinc alloy soldering.

Also some prices are simply...let's say puzzling: the Welco 52 can be bought at 10.05 USD a pound...
I found e bay from France best prices, but then I've got it near my home in Tenerife which is fairly strange to my. but dinkum. (true)
Kevan,
I saw something very similar to this product at Sandown Engineering Exhibition December 2010.
The guy will probably be at Alaxandra Palace Engineering Exhibition from fri-Sun 21-23 Jan 2011.
Sorry I don't recall the name of the product
Jack
steam_cannon (author)  Kevanf13 years ago
I called around and got some info for you.

You should be able to order a cheap 8 pack of rods from Harbor Freight for like 15 dollars plus shipping. Harbor Freight also gave me their international orders number (805)388-3000.

For the exact product I used in this instructable, you would order from these people in the US or here for the UK.

And FYI, I'm not associated with either of these companies.
Have you seen the butane micro-torches?
I got one about 11 years ago while I was in Australia. Pencil shaped and pretty good once it's lit. I find I have to cover the vent holes at the bottom of tube to light mine though. Perfect for this sort of work.
Wow! Cheers 'steam_cannon' this goes above and beyond the call of duty and I'm very grateful for your hard work.

Thank you and have a great new year.

Kevan
Reffner3 years ago
I love brazing. I learned it back in school in shop class and most of the time prefer it over welding for it's simplicity and strength. If done correctly and with the correct brazing rods it's stronger than welding, and the only way to affectively secure dis-similar metals together. Thanks for sharing this.
I do agree!
shilohjim3 years ago
Is it food safe? Can I join copper tubing with it and be safe about what goes through it?
Bare copper and Zinc are not safe with food. If you use copper you can tin it inside with pure tin or 96-4 tin silver and flux. It's valuable on small pieces but on long pieces that becomes almost impossible. In this it's better to use stainless steel 304 which can be soldered with 96-4 tin silver with Stay Bright Harris Flux; that's perfectly safe.
Never use plumber tin as many times it contains lead.
steam_cannon (author)  shilohjim3 years ago
No, I don't think so.

You probably want to use a food safe solder for that like "450 Soft Silver Solder". I wrote you with some more details...
pfred23 years ago
You got guts. Is that bushing on the left in your top picture even connected? Some borax or something might help your flow out a little. It can't hurt to try.
steam_cannon (author)  pfred23 years ago
The bushing is connected quite well, though normally you would weld a container for a bushing and not directly to a bushing itself. So in part that was an experiment to see if I could weld to a powder cast bushing and apparently I can. I'll keep the borax idea in mind, but really this material flows quite well without any additional flux.
You think? Because I think you're not doing nearly enough prep work. Try this:

Clean your weld area with a stainless steel brush that you only clean aluminum with.

Clean your welding rod with garnet paper or something that isn't oxide based. Plain sandpaper is aluminum oxide so it is no good. Plain Steel wool is no good either as it has carbon in it that may lead to weld contamination.

Get back to me and let me know what if any differences you see. I'm going to bet on night and day ...
steam_cannon (author)  pfred23 years ago
I think you must be pushing the issue because you're experienced in other types of brazing and welding, as am I. However with products like Alumniweld and Duraweld, the oxide coating is not much of an issue. So I think you need to read more about these products or try them yourself. You could even follow their instructions and see how that works out for you. ;)
Sure just as soon as my Miller TIG welder breaks down. Ha!
steam_cannon (author)  pfred23 years ago
Regarding your argument, basically it sounds like what I hear from the snooty guys who work in bike shops that give my girlfriend a hard time over her $300 bike because she didn't pay $3000 for it. What's more important then snootiness are the real problems this method solves for people.

So I think you're being old fashioned. I can TIG weld in the shop, but I can also keep welding tools in my toolbox , fix parts right on the dock, you can't. I can also work with fine jewellery size parts and thin metals that you can't. Your methods are limited. But to each his own.


I guess you never saw this:


p9290011.jpg
steam_cannon (author)  pfred23 years ago
I have an oxygen torch too. So what. My point stands, you're old fashioned.
You can make perfect welds on aluminium with a oxy-fuel torch. Even superior to TIG in some cases like "dirty" castings and sheet metal work with a 2XXX alloy..
Oh come on I have quick disconnects on my mixer how old fashioned can I be? When I saw someone else with them on a job I just had to get me some. They're nice they let the hose swivel.
Aluminium oxide is a big issue. No metal apport will stick on oxide. Clean, clean and re-clean. Rubbing with methanol followed by brushing with a SS brush,
For Zinc-Al rods (a very old method for joining aluminum and pot metal) the cheapest at my knowledge in the States is the Welco 52 at Welding Supplies. About 10.05 US dollars a pound...compare with the others!!! Melts at 732 F
(390 °C)

All the other stuff have similar composition, there is no brevet as it has been used for more than 80 years. Warning: it's a soldering/brazing rod, not a welding. Do not use it for structural purposes, and it's not resistant to corrosion (salt water etc...).

Also for joining copper to aluminum; tin 95-5 antimony, and tin 96-4 silver can be used also, and it's food grade. For some applications in corrosive medium it's better as the tin is almost impervious to corrosion. Melts at 225° C. Fluxes required.
bobzjr2 years ago
Thank you so much for putting this info up!
On many occasions, I have wanted to join metals without using screws.

But I thought it would require a much more complicated traditional welding process. This opens up many more avenues for making things!

I'll be running to Harbor Freight this weekend.
steam_cannon (author)  bobzjr2 years ago
Have fun and let me know if you have any questions.
tonyscott3 years ago
hi guys, there's a product called DURAFIX and you are able to sold togheter alum to aluminium with a butane torch it needs only 390 degrees celsius. ther are many videos abuot it on you tube. for does who don't know! of course.
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