Project 5 by cbmkr: Gas Welding Aluminum

Thought i would give some alternative to welding aluminum for those repairs where no power is available.

Oxy Acetylene Torch : Victor 100C W/ Victor #2-T-13 (Standard oxygen acetylene gas bottles)

Aluminum Gas Rod Harris Cor-Al 3/16" flux cored Aluminum Brazing Alloy Rod ( Gas welding rod not Solder)

Material 11 ga 3003 aluminum sheet

This product is not the same as the short 18" solder rods you see at trade shows ect, That material will actually overtime turn black and corrosion will separate it from the base material. It is a common material used in boat propeller repair.

I have done this for approx 35 years and in a pinch it will work just fine,I saw a body man at Peterbilt in Kansas City using this in the 70's repairing wrecked cabs, bought some rod and taught myself how to use it.

Normal cleaning is required if you can, if not heat the material if it is dirty and keep brushing with stainless brush until it appears clean. Heating is a must and the part or sheet in this case must be brought up to the molten state, this is where the tricky part comes in ( you can loose the base material real fast),the rod will melt quickly and when you see the material start to soften push the rod into the puddle pull out heat and keep on going.The puddle look will be determined by how molten the weld area is.

In this demo i had a lap joint to weld and added a couple of holes to repair.

The pictures show the progress and appearance of the weld, As you can see the finished weld is not clean at all the flux from this is nasty and flows everywhere.

But the weld ended up pretty nice , not tig quality but it works.

There is a pic of cross section after the welded sheet was cut and one after that piece was clamped and bent.
you can see from the photo that the weld held up just fine.

This is a great alternative to Tig repair on aluminum when power is not available.Works great on aluminum castings pipe sheet and extrusions.

Attachment 8035Attachment 8036Attachment 8037Attachment 8038Attachment 8039Attachment 8040

That flux sure will make a mess of your work (corroding and oxidizing it over time) if it's not completely removed after welding. I find in most cases, for most real world welding conditions, completely removing the flux after welding is not practical. I hear there are some strong acids that can remove the flux in areas where you can't mechanically scrub (high % nitric?) but I never tried it. How do you prefer to remove the flux afterward?

I used an old school "Purox" oxy-acetylene welding setup on aluminum before I got my TIG setup. I just started working again on one, really old cast aluminum project that I initially began quite a while back with oxy-acetylene welding, but had to table it because I couldn't finish it due to the heat control limitations of that process. I am finally getting around to finishing it off with TIG process. Encountering oxy-fuel flux inclusions inside aluminum when TIG welding is kind of interesting.

The flux turns back to a liquid state after the material cools down and then dries out,It is easily removed with water.I also forgot to mention after using the rod you must smash the end flat to keep the flux from leaking out and drying.Here is a picture of the weld cleaned with water and wiped with acetone, also included is a weld that was done earlier this year on my 34 year old water pump housing that was cracked from not getting completely drained.This one pumped over 90,000 gallons of water for us this summer with no problems at approx 90 psi head pressure.

Attachment 8049Attachment 8050

The weld on the left side looks like you've cleaned the flux off by a combination of solvents (water + acetone) and by mechanically scrubbing with a wire brush. That's the way that I also know how to effectively remove the flux, but mechanical removal is often not practical on the back side of many welds (such as on your water pump example.)

That water pump pic is also actually a good example of the aluminum corrosion that I was talking about (whitish powdery residue). While it hasn't eaten away enough of the aluminum to cause failure, it could do so eventually. And if you were to remove the corrosion that is visible now, it will just come back due to the unremoved flux. The flux/corrosion is like a "cancer of aluminum".

The corrosion will even occur on parts not directly exposed to water. Wherever there is flux in contact with the atmosphere, water droplets will form, due to the hygroscopic nature of the flux.

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Originally Posted by cbmkr

Thought i would give some alternative to welding aluminum for those repairs where no power is available.

Oxy Acetylene Torch : Victor 100C W/ Victor #2-T-13 (Standard oxygen acetylene gas bottles)

Aluminum Gas Rod Harris Cor-Al 3/16" flux cored Aluminum Brazing Alloy Rod ( Gas welding rod not Solder)

Material 11 ga 3003 aluminum sheet

This product is not the same as the short 18" solder rods you see at trade shows ect, That material will actually overtime turn black and corrosion will separate it from the base material. It is a common material used in boat propeller repair.

I have done this for approx 35 years and in a pinch it will work just fine,I saw a body man at Peterbilt in Kansas City using this in the 70's repairing wrecked cabs, bought some rod and taught myself how to use it.

Normal cleaning is required if you can, if not heat the material if it is dirty and keep brushing with stainless brush until it appears clean. Heating is a must and the part or sheet in this case must be brought up to the molten state, this is where the tricky part comes in ( you can loose the base material real fast),the rod will melt quickly and when you see the material start to soften push the rod into the puddle pull out heat and keep on going.The puddle look will be determined by how molten the weld area is.

In this demo i had a lap joint to weld and added a couple of holes to repair.

The pictures show the progress and appearance of the weld, As you can see the finished weld is not clean at all the flux from this is nasty and flows everywhere.

But the weld ended up pretty nice , not tig quality but it works.

There is a pic of cross section after the welded sheet was cut and one after that piece was clamped and bent.
you can see from the photo that the weld held up just fine.

This is a great alternative to Tig repair on aluminum when power is not available.Works great on aluminum castings pipe sheet and extrusions.

Attachment 8035Attachment 8036Attachment 8037Attachment 8038Attachment 8039Attachment 8040

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Just saw this link on gas welding aluminum. I gas welded aluminum before I Tig welded, I still do when I have aluminum auto body parts to do Tig is to Hard and to much grinding. Got taught by a English man who made airplane part for Rolls-Royce. We used a aluminum brazing rod with Aladdin welding flux you could hardly see the weld and strong number one trick was the welding glass you need cobalt lens hard to get have been banded in most places because people used them to drive to dark and can't see long distance very well. #LBX-5Attachment 8228 Cobalt Blue LBX-5

There is a big difference between a braze and a weld. Each has pros and cons. The right process for the right job.