View Full Version : Soldering/Brazing aluminium

10-25-2006, 12:23 AM
Has anyone used AlSoder 500 or Al-Braze 1070 from Harris?


I've tried those magic soldering rods that you see at trade shows and have been disappointed with them. They plain simply don't work well on aluminiums.

I figure Harris is a reputable manufacturer so their stuff must work, and at least I'm hoping.

What I really need is A/C tig welder but considering how infrequently I'll be using it, I just can't justfy spending that kind of money.

10-25-2006, 07:52 AM
I've used Aluminium solder but the flux is very dangerous if memory serves it contains fluoride compounds but it definately works.
Better to stick to mig or tig welding

10-25-2006, 08:07 AM
The biggest problem soldering alumnium is there is a VERY narrow heat range from soldier to MELT DOWN! Lots of practice before doing anything important is recomended!


10-25-2006, 10:09 AM
The stuff that the local guy in Michigan sells works real good, Using only a regular propane torch. he does everything from pop/beer cans to alum castingings from lawn mower engines. He does stress that it will take some practise to do it. And above everything else, use only a stainless steel brush to clean the area to be soldered. And use it only for that. Also that you use a stainless steel fork to keep the scrum off the top of the solder pool as you work. My fork has only one tine and works well. I have done about 14 aluminum sheet cages bottoms as replacements for parrot cages with from for to six joints. in two years of use only one has broken. the second best thing for welding aluminum is the cobra O/A torch http://www.cobratorches.com/ I have one and it works great it is used by alot of Farriers for doing the aluminum shoes, the cleats and traction devives. Uses 4lb of oxy and Act at the torch tip, other than cutting then it uses 10lb. It does take a little getting use to with the pistol grip and all but I like mine better than the long style. the video they have is great. I haven't done alot of aluiminum welding with it but have been happy with the results. It does cast iron great to.:D
the other thing it costs a whole lot less then tig. if you don't have the use for it.

10-25-2006, 10:41 AM
I see Henrob has changed it's name. Those torches have always interested me, but I have never been able to justify the cost versus the amount of use I would get out of one.

The Mad Dog aluminum solder and others of that type are somewhat different than the Harris. As Glen says, they take practice and require cleaning of the area with a stainless brush, used for nothing else to prevent contamination. Use a low heat to melt the solder in the joint, and then use the rod or a stainless scratcher to scrub the joint under the puddle and it will work.

The Harris solder says it will work on solderable alloys. It does not say what these alloys are.

10-25-2006, 04:24 PM
Don't know if this is going to work as the print is small and the page is 14 " longI've loaded them to the bucket site
http://i35.photobucket.com/albums/d200/ptsideshow/insts01.jpg is the first part.
is the last part of the first page.
This is the other side. the only thing I didn't include is the add for product:D
I'm a friend of the guy that does the demo's at NAMES every year.

10-25-2006, 05:00 PM
I just ran across this website.


I've heard of Muggyweld stuff, but can't remember if 'good', 'bad', or ???
They list products for aluminum, pot metal, cast iron rods, and a heat sink/fixturing putty that looks handy. Of course they're not exactly giving them away for peanuts.

Anybody here ever use any of their products?
Their site does have a lot of interesting short video clips showing the techniques.

10-25-2006, 05:29 PM
Finally something I can offer some advise on.
You must make sure to brush the area to be soldered with a stainless steel wire brush that has not been used on steel or anything else.Buy a new one specifically for this purpose if you have to.I keep mine in a plastic bag to avoid any contamination.
I use the fluxless rod that has been around for years,it's called Ideal720.
The process goes something like this:
Scrub the area to be soldered with the SS brush.Heat with propane,or whatever you have,but don't put the flame directly on the soldering area.If you do ,brush it again.
Scrape the solder rod gently on the area until it melts,then run a short bead.This will happen very fast,so be ready.
Then you use a 1/16 piece of stainless steel rod to "scrape"through the puddle until you feel the aluminium softening underneath.What you're doing is scraping off the oxygen from the surface of the alloy,which is what prevents solder adhering.Now you move the solder along the joint with your ss rod,adding a bit more solder if required.
I generally use a sanding disk to clean up the area,since it will look as rough as a bear's behind.I have used this process many times,making alum. mufflers for model aircraft,and most are still in use after several years.
Hope this is of some use to someone.

ps.My apologies,this is exactly what has been described above:).
Oh,well,I got my name in the paper:D.

10-25-2006, 06:08 PM
For those of us who lack a tig welder:

I've used some of the goofy "fluxless" rods you talk about and was really impressed. From what I have read, these are not really fluxless--rather the flux is just imbedded in the rod material. Initial cleaning with a stainless brush along with lots of "rubbing" of the rod over the work to keep removing the oxide layer as it forms are both keys to making them work. You have to add new material below the oxide layer so rubbing the rod in the bottom of the puddle is the correct way to melt it in.

I saw them at tool shows and never bought the snake oil pitch. I once bought some fake chamois at a car show where the guy hawking them demonstrated them with diet coke. They worked great with diet coke in carpet and lousy on a car with water...but I digress

I found something similar at HF for less money and bought it with a healthy dose of skepticism. I used it to build up a broken mill knee handle which is more cosmetic than anything else, but it turned out OK. It involved building up a large portion of the boss through which the handle attached....a huge portion of it was just missing and allowed the handle to just flop around.


Since aluminum does go from solid to liquid in a very short temperature range, the propane torch is preferred to the oxy-acetylene torch for use with this stuff.

Edit-- I forgot to add that the handle involved was actually potmetal of some sort. Polishing made it very clear that it was not all aluminum. Potmetal, due to its zinc content welds even harder than aluminum since it has an even shorter temperature window before it turns into a puddle on the welding table.


10-25-2006, 08:00 PM
Then you use a 1/16 piece of stainless steel rod to "scrape"through the puddle until you feel the aluminium softening underneath.What you're doing is scraping off the oxygen from the surface of the alloy,which is what prevents solder adhering.

That's a novel approach. I still have some of those alluminium soldering rods which didn't work. I'll try your technique and report back. Thanks.

10-26-2006, 06:34 PM
The rods from the trade show guys are pretty much just zinc. It works OK if you don't put too much heat on it and burn the zinc, and you "scritch" at the aluminum with the rod as it all is being warmed up.
In my experiences with the stuff, it does not penetrate or flow into a gap worth beans, so veeing the joint almost all the way through is required if you expect a decent joint.
It is quite a bit harder and less flexible than aluminum.
Once you use the stuff on a part, you can pretty much forget about going back and welding it conventionally, as the burning off of the zinc will cause greif.
FWIW these can be had at Home Depot and other stores that stock Bernzomatic propane torches and rods.

There are a couple aluminum welding/soldering rods out there that use a eutectic alloy (or nearly eutectic) meaning that the alloy melts at the lowest temperature possible. They make a nice joint that is aluminum, but require flux, and heat rather closer to the melting point of the part than many wish to apply.
Beyond that, you have to go to an actual fusion weld process.

Trevor Jones