Noob here, o/a aluminum welding

[mechelement]

I'm new to o/a welding and just picked up my first outfit, Victor medium duty kit and a #2 welding tip. My uncle showed me some o/a welding and I tried it out and really liked it. I only know some basics.

I've designed, cut and laid out a horseshoe rack for my farrier (horseshoer) truck. I made it out of aluminum thinking one of our friends would TIG it, but my fiancee ran out and bought the aforementioned o/a outfit for me. I spoke with Norco (supplier) about welding the 1/8" wall thickness 1"x1" square aluminum tubing and they suggested WELCO COR-AL and the #2 tip.

I finally got a solid welded section which survived the hammer, but it looks really ugly. I set my oxygen regulator to just under 5lbs and the acetylene regulator to 4lbs. I use a #2 tip with a carburizing flame, 60-70* chamfers for butt joints and 1/16" spacing as per the COR-AL recommendations. I heat up the joint evenly until I can see a dark red/black glow starting to appear at the joint, pull the flame away and ready the filler. Then I hit the joint again and start dabbing the filler into the joint. That stuff takes off like a bat out of hell and I can only get a few dabs before the flux goes over the top of the filler that actually set and the remaining filler beads on top and the joint is mostly full.

I've tried ~50 times to get this down and this is by far the best fusion I've obtained. Before I didn't heat the joint up as much and when I started with the filler, it would bead up and the flux would spread rapidly. I've tried the #0 tip and couldn't get a solid weld and it would bead as I just mentioned.

I've been brushing all joints with a SS brush vigorously to ensure a clean surface.

Any guidance would be greatly appreciated.

[El_Lloydeo]

there is a guy they call the tin man who makes a nice video on oxyfuel welding of aluminum. he then will use an english wheel to straighten it back out. hes pretty darn good with it too. but watching him it doesnt look as hard as one might think. the flame is quite different than for steel and he uses a water based flux. i wanna say chloride or something. i cant remember. i have the video at work but have to take it back soon. i took notes on it. let me see if i can find them. i think its called gas welding aluminum.

[tapwelder]

Isn't that a brazing alloy?

Try a tig rod with proper flux.

Do a search several there have posts on o/a welding Al. I have some fluxes from Welco and Esab, sorry can't thing of the specific numbers. I have listed them before though.

[makoman1860]

Al-CORE is a brazing material, not welding.

If you want to weld, use the traditional welding flux such as Allstate 35 from Esab, or Kents from www.tinmantech.com. Fillers depend on your base material, but are the same as any other welding method ( i.e. TIG ). You are going to want a tip much larger then a Victor #2 for .125" material. If your doing butt welds I would start out with a tip size of about .073", which is about where a Victor #4 is. If your doing "Tee" welds go up another size yet. Use a Hot flame for tacking, and back it off a bit to a quieter flame for welding. Once you start practicing you will know why . Flux is mixed with clean drinking water to form a paste, applied to both sides of cleaned metal, and the filler. Warming the aluminim a bit with the torch before fluxing helps it dry quickly and stick.

[mechelement]

I mentioned to the folks at Norco I wanted to weld aluminum and everyone there said it wasn't possible. They went by the Victor tip chart which denotes a #2 tip for 1/8" thick material. Aluminum dissipates heat much faster than steel. I'm going to head back up there today and pick up some of that flux, a #5 tip and some TIG aluminum welding rods. Most of the welds will be tees.

So use a neutral flame and set regulator pressures per Victor tip chart for a #5 tip?

[makoman1860]

Originally Posted by mechelement

I mentioned to the folks at Norco I wanted to weld aluminum and everyone there said it wasn't possible. They went by the Victor tip chart which denotes a #2 tip for 1/8" thick material. Aluminum dissipates heat much faster than steel. I'm going to head back up there today and pick up some of that flux, a #5 tip and some TIG aluminum welding rods. Most of the welds will be tees.

So use a neutral flame and set regulator pressures per Victor tip chart for a #5 tip?

Im not supprized, most welding suppliers know squat about welding in general. As far as pressures you can go by the victor chart, it wont affect anything one way or another. Gas pressure in reality means nothing to flame velocity since your torch valves are controlling flow, but lower pressures make adjustment at the torch easier. Neutral to a slightly fuzzy reducing flame, avoid oxidizing at all times. Clean your parts with clean rubbing alcohol, then brish with a clean stainless brush, then re-wipe with alcohol.

P.S. get 3/32 or 1/8 filler, it acts as a heat sink and makes welding go much easier for the beginner.