Welding Aluminum

[aeronca65t]

I've been wondering about welding aluminum (without a fancy MIG or TIG welder) and I've heard that there are aluminum welding rods that can be used with Oxy-Acetylene. I was having my Oxy-Acet tanks re-filled a few weeks ago and I asked the guys at the gas place about this. They ended up selling me some rods called "Aladdin Aluminum Welding Rods" (for Oxy-Acetylene). Weren't real cheap and I was wondering if they were a "snake oil" product. Just used them a few days ago and they work great! I'm not sure about tensile strength or brittleness, but they seem to do a decent basic job for repairing or joining aluminum pieces. For non-structural repairs, I'd say they do a decent job!

 

[DougR]

I can't remember the product name of the aluminum BRAZING rods I got. They melt with a propane torch, and can repair aluminum or pot metal. The pot metal brazing is trickey because it requires supporting the metal before melting. A fun product though.

 

[Lotus]

i know that you need a special type of aluminum, but thats it.

 

[piman]

I owned an aluminium bodied car that needed some welding done to it. Being fairly accomplished in oxy acetylene welding of steel I thought I would try. It does take some practice as it does not change colour with temperature as steel does.
You need a special flux and it helps to use blue
lenses in your goggles as the flux is very bright.
Old metal is harder to weld than fresh (my car was over twenty years old)but I managed what I needed to do. Practice on some scrap and use a soft flame. Good luck.
PS there are some aluminium rods that can be used on castings etc that other respondents mentioned; these are not true welding rods as the parent metal does not melt, but I don't think they will work well on sheet aluminium.
Piman.

 

[CraigFL]

A lot of the rods they sell to "weld" aluminum are Nickel which actually is more like brazing since you generally don't melt the base aluminum. This works good for parts that aren't under a lot of stress. If you need structural welding, it needs to MIG or TIG.

Also, you can solder aluminum but it can be tricky. I used that to fix pinholes and attach ground wires...

 

[aeronca65t]

You are correct....the Alladin "welding" rods are more like a form of brazing (mechanical heat bonding) than true welding......the AL base metal should not reach melting temp in the process. These rods contain nickel, zinc (and some other stuff I can't remember at the moment) and involve "tinning" both base pieces with the rod material (and then heat bonding).
I've tried true AL welding, using a rich torch with oxy-acetylene.....I'm useless at it!

 

[piman]

AORONCA65T
Stick at it; because aluminium is a good conductor of heat you need a bigger size nozzle than for the equivelant gauge of steel. Initially it takes time to reach fusion temperature but then you need to be careful, especially with thin gauges, and be ready to back off the torch.
I found that thicker material was relatively easy to weld with oxy (say 1/8") so practice with that.
As I said earlier blue lenses make a big difference. I believe that inert gas welding processes have aproblem on vertical welds, exactly the sort of work you may need to do on a car.
Alec

 

[aeronca65t]

Thanks for the encouragement, but after 30 years of trying, I'm willing to admit it's not one of my strong points! I've done oxy-acet "spot welds" in AL and then hammer-welded the joint together, but it never looks that great. I just replaced a "scab patch" riveted plate (non-structural)on my Aeronca last week using these Alladin rods and it looks great(that was the reason I bought them in the first place)....we'll probably try this on other planes as time goes on. I do have access to a TIG welder for bigger jobss....TIG is pretty easy, but I don't have a real need to weld "thick" aluminum.
You're right about the blue lenses....much better for aluminum!

 

[tlthorne]

it can be done with just some of the same metal
(sheet) cut into thin strips, the flux is very
important, there are some differences in brazing
and welding flux, the blue(cobalt) cuts out the orange flare produced by the flux. if you are going to do alot of aluminum welding please note
that colbalt glasses do not filter U/V from the
flame, it can cause early developement of cataracts(not good) dimimium(sp)lense are recomended! i use a henrob(dillon) torch but any oxy/acet torch will work. practice is the only way
to learn. getting the metal clean is very important for making a good weld.
the rods that you use with a propane torch are
high in Zinc, it makes for a brittle weld, proably
need the softer weld as to hammer it smooth when
metal finishing. i dont have the numbers in front of me here, but if you would like more info i can pass it along.
Good luck with your project!

tt