Welding Aluminum

[fitzgr8]

I need to tig and old bulkhead from a snowmobile for a friend of mine and was wondering if anyone has any tips. I know how to weld new/clean aluminum but am not used to old dirty stuff. I do have a stainless steel wire brush to clean the area up good. What filler rod should I use.

Thanks,
Fitz

 

[MoonRise]

Tips?

Clean it. Clean it really-really well.

Remove grease, oil, dirt, paint, etc, etc. That usually means using some sort of solvents, so Be Safe.

After you remove any and all 'foreign' stuff, then you can get to wire-brushing (or using a carbide or steel burr in a die grinder, etc, etc) the aluminum oxide layer. Then wipe it down (both sides!) with some more solvent such as acetone (again, Be Safe! ).

Then you can get to the welding aspect of the job.

Filler? That depends a LOT on what the original (parent) material is.

 

[USMCdodge]

make sure you are using the right settings on your machine. if its dirty, set the balance to cleaning, use the green tungsten and I would NOT use solvents. when you burn them they are very bad for you. try pre-heating the metal, run an arc over the area your welding before you weld it. Not hot enough to melt, just to make the metal shiny and get the white oxide on the sides. you really have to take your time. I usually don't weld more than 6 inches before i let it cool down for a minute. The cleaner you can get it the better
Good luck!

 

[54stude]

Do not use brake cleaner to clean the metal before welding!!!
Check out this link to see what could happen.
http://www.brewracingframes.com/id75.htm

 

[gbsmithy08]

If you can fully tear it down to were there is nothing that warter will hurt you can take it to a place like some Napa auto parts that has a parts washer and have them clean it. Which is steam cleaning it. Like others have said do not use chemicals as it is bad for your health.
One other way is if you have a Oxy Acetylene torch setup you can light your acetylene only and run the torch over the bulkhead, coating the aluminum with acetylene soot. By doing this it will tell you how hot you can heat up the bulkhead with out melting it. You will beable to set your torch setup with a rose bud (big heating nozzle) to heat the bulkhead with.
When the soot starts to disappear then the aluminum is getting hot enough to clean it and also weld it better as it will be pre-heated.
Once your done welding it you might want to wrap it in old leather welding coats or fire bricks to let it cool slowly so it wont crack or warp.
This was the way I used to weld aluminum heads for sprint cars or motorcycle motors in college shop classes.

 

[dkGoodrich dot com]

Use acetone to clean prior to welding.

Tungsten color depends on what kind of machine you are using, inverter and transformer based machines call for different kinds of tungstens.

If this is your first shot at welding old aluminum, you should practice on some scrap first.

Type of filler depends on type of aluminum.

You can make light amperage passes across the material with no filler, not hot enough to pool the material, this will help clean and preheat the material before you actually weld it.

Setup wise, it really depends on machine.

 

[zmotorsports]

Clean it, clean it, clean it and then when you think it is clean enough, clean it again.

As far as tungsten, if using a transformer machine use pure tungsten (green band) and if lucky enough to have access to an advanced squarewave inverter machine the use either Ceriated (orange or gray band) or 2% lanthanated (blue band) tungsten. Personally I think the 2% lanthanated carries the higher currents better especially on A/C.

When welding snowmobile bulkheads I have had good results with 3/32" 4043 TIG rod. Wipe the rod and the work down with acetone just prior to welding. If it is a large mass where the weld needs to be performed I have also had good results with pre-heating the area with a heat gun prior to striking the arc. With the proper pre-heat the weld will get great penetration as the aluminum is sometimes difficult to get enough heat into it due to the fact that it dissipates the heat so rapidly.

If using a transformer machine set the DIG (or balance) to a slightly lower number (~5) for better cleaning action. If using an advanced squarewave machine I generally set it at about 68% EN. If the aluminum is exceptionally clean and of good quality those numbers can be bumped up to ~7 for the transformer machine and the approx. 70-72% EN for the advanced inverter machine.

Depending on the thickness you may also wish to put a "V" in the area to get better penetration as well.

Mike.

 

[csargents1546]

Check this out, got it a few years ago.

http://http://www.aluminumrepair.com/aluminum_repair.asp

I have used it to rebuild a part that was broken on a 60 year old traffic light. Pretty cool stuff.