Quick and Easy Brazing Aluminum, Copper and Nonferrous Metals

Intro: Quick and Easy Brazing Aluminum, Copper and Nonferrous Metals

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!

STEP 1: Melt Brazing - Making Candle Sticks

My first weld type I will describe here is typical "Melt Brazing". It's just heating the metal then touching the metal with the brazing rod to see if the rod starts melting everything together. In this example I'm making some candlesticks welding copper to aluminum. Typically that would be very difficult to do, but with this system it's very easy.

STEP 2: Melt Brazing - Making Candle Sticks Part 1

Select the materials for your project.

Here I cut two pieces of aluminum stock metal (2’ x 3’ x 1/8’) and picked out some copper 3/4' adapter pipes.

STEP 3: Melt Brazing - Making Candle Sticks Part 2

Here I’m heating the metal on a heat resistant surface. I’m heating both pieces with a hand torch and rubbing the brazing rod against the metal. When I'm not applying heat, I touch the metal with the brazing rod to see if it will melt. When the rod starts to melt then the metal is hot enough. So I’m wetting the copper and the aluminum with this melted metal, like melting a crayon. Then I'm applying a little more heat so everything melts together.

STEP 4: Melt Brazing - Making Candle Sticks Part 3

Then I let the parts cool, it's best to let the metals cool slowly in the air. Then I test the welds.

STEP 5: Melt Brazing - Making Candle Sticks Part 4

Then I clean up the copper with fine "0000" polishing steel wool. Salt and vinegar can also help to clean it up. Then I file off any burs and it's good to go. 

This is about as easy as soldering, but works on metals that don't easily accept solder. In fact if I was soldering copper to aluminum or aluminum to aluminum, this would be my preferred method since it requires no flux.

STEP 6: Blob Brazing - Bicycle Kick Stand

Here I'm adding a foot to a bicycle kick stand so it doesn't sink into the grass. Most kick stands are aluminum like this one so here I'm brazing aluminum to aluminum. I call this the blob method because the alloy is melted and applied as a blob. This is my own method, though I'm sure other people do it too.

STEP 7: Blob Brazing - Bicycle Kick Stand Part 1

I briefly filed the surfaces of the kickstand since it wasn't too clean. Then I broke the alloy stick into segments and put them in place to melt with the flame as I heat up the metals. Also I'm moving the metal pieces a little to be sure the alloy gets everywhere it's supposed to. Though if the pieces are secured in a vice then I'd just poke the blob with an unbroken alloy rod to move the metal around if needed.

STEP 8: Blob Brazing - Bicycle Kick Stand Part 2

Here you can see the metals melted together by the torch. This is very strong. This upgrade took about 1 minute of time to set up and get the metal in place. Then another minute of cooling time. 

STEP 9: Some More Examples

Here are some more examples of both melt and blob brazing methods. Each example is challenging in it's own way, but possible using this brazing method.

* Cup: This cup is made from a discarded can. The metal is very thin so I cleaned it and used the blob method to braze a handle onto it. Though keep in mind that this cup is plastic lined as contact with this particular alloy is not intended for food use.

* Coin: This is a coin for a magic trick. I used a blob welding method, but blob or the touch &  melt method would work. (Note: The depicted big-y coins are not us-currency.)

* Bushing: This is a powder cast brass bushing. It would be easier to use a copper tube, but if you wanted to weld on a bushing like this it's not too hard. It is saturated with oil so first you need to burn the oil with the torch. Then position it and braze it. After the item has cooled, polish it and oil it.

Comments

[heathersharmony]

I’d like to join old copper pennies and old silver coins together. The pieces needs to withstand a gentle bend to curve. Would this work?

[InstructablesSA123]

Hi. How do I solder/braze copper pipe to stainless steel
pipe. What is best, solder or braze and what type of materials do I use, re. rods
with flux or without - high flame or low flame? I am a total novice in this regard. Thanks.

[terrybb]

I want to join copper rod to copper angles. I do stained glass and plan to creat a support for butterflys on the copper rod and support them by soldering them to an elbow rod. What do you recommend to join the copper rod to the copper elbow?

[SabinaCowan]

wonderful, thanks for the info.

[NickS21]

I want to make this from galvanized chain, would this method work, thanks.

[lowiron]

Hi,

I would just like to add a few comments here. I am a maintenance tech and do most of our welding and fabricating at work. A few years ago newbie in our maintenance department introduced me to the HTS 2000 aluminum repair rods. I had heard of this type of material for years, but had never actually used it. One night an aluminum casting on a conveyor roller support had been broken during a mechanical failure of another part of the conveyor. It just so happened that we were out of all types of our aluminum brazing/welding rods, and the supervisor said to toss the part because we can get a new part locally the next morning.

The new kid called me over to the weld area and showed me that he had several sticks of the HTS 2000 in his tool box. He asked if he could try joining the pieces of the support back together so they could operate the conveyor. I told him to go for it because I was curious. I have heard professional welders refer to this type of filler metal as "aluma-crud" and other derogatory names. The kid used a stainless wire brush and brushed the snot out of the pieces. he then soaked the pieces in plain rubbing alcohol, then blew them dry with compressed air. He borrowed my small Smith Aircrafters torch and got busy. When he was done he bounced the support on the cement floor and it held together. That same support was put back on the conveyor, and is still function today running almost 24/7.

I agree that this type of filler metal should not be used in critical areas where failure may lead to injuries or expensive repairs. However, I find that it is very useful when used within it's limitations.

I would also like to point out that I would not use this type of filler in medium to high vibration scenarios. It appears to leave a somewhat more brittle weld joint especially when used on some types of cast aluminum. Here is a little secret I will share with others who are interested in aluminum repairs.

There are several name brand types of flux cored aluminum rod. Some will flow at around 800-900 degrees F. Others flow anywhere from 900 -1150 degrees F. I have found that these flux cored rods/wire are less time consuming because of less preparation needed, and that a few of them will be a closer match to the metallurgical properties of the item needing to be repaired.

AL-Cor made by Harris flows in the 700-800 degree F range with excellent results...Approx $17.00 for a roll that is 36" long. It sounds like quite a bit for so little, but a little of the AL-Cor goes a long way because it flows so well.

Other higher temp aluminum filler metals that are flux cored would include Aufhauser 1/8"x20" flux cored rods at approx. $50.00 per 2 pound package. Another product by Harris is their CORAL60. This too is 1/8"x32" rods at I believe approx. $55.00 for 3 pounds. I actually prefer the Aufhauser because it seems to flow a little better than the CORAL60. These flux cored aluminum rods/wire are great for those who are not well versed in welding, and often result in strong permanent repairs. I have used all of the above with excellent results, but usually only when I have a serious case of the lazy bones. Normally I prefer the good old tried and true Oxy/Acetylene torch, bare aluminum filler metal, and flux. To me there is something relaxing about gas welding/brazing. So.........pick your filler, and happy aluminum joining.

[gathem]

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]

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.

[Vijaykumar123450]

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.

[Kevanf1]

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]

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]

The prices on eBay aren't bad. :)

[Kevanf1]

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.

[Ilan Voyager]

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]

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.

[Ilan Voyager]

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]

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.

[Ilan Voyager]

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]

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.

[Ilan Voyager]

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...