Gas Welding Joints & Beads

I have never done MIG welding so I'm not the one to ask. I have used MIG wire for 4130 because you could buy a spool of small diameter weld wire for doing delicate parts.
 
In the olden days, aluminum welding flux had to be cleaned off thoroughly or it would cause corrosion. I don't know if modern flux has that undesirable feature.
 
You still have to rinse it off. I use a fine wire brush and some warm water.
 
erikmannie said:
Regarding not seeing the puddle in aluminum while gas welding, isn’t this the same as not seeing the puddle in aluminum while TIG welding?

By the way, this is why I prefer TIG welding on steel rather than on aluminum because of not being able to see the keyhole. I only choose aluminum when steel will not suit the application.

Honestly, I find steel to be very user friendly, but I have yet to warm up to aluminum as a material for welding.

We are lucky to have TIG as an option for welding aluminum, as the aluminum stick welding electrodes are a challenge (although once the base material is warmed up they will function).
Click to expand...
I hope not! I definitely see the puddle when TIG welding aluminum. I find it easy to see actually. You should have a good puddle and each dab of the filler causes that spot to solidify as soon as you move past it. That's how you get the nearly mirror finish beads...adding the filler freezes the puddle. If it's a frosty finish it had too much time to cool and glazes over.

What often happens is people try welding aluminum like steel and do a couple of things wrong. One, they ease into it on the peddle from the start which only gets the base metal hot. You want to go full pedal to get a puddle in a max of 2-3 seconds (1 second is better) and then move fast...dab, move, dab, move with a purpose. When people go too slow, or use too little heat, it winds up taking longer, which puts more heat into the work, and things start to melt and you get a big blob rather than a bead with a small puddle at the front. It's sort of the opposite of steel in many ways...you're better having too many amps, and moving a bit too fast than the other way around.

I got one ten minute demonstration from a buddy and after that I spent 30-60 minutes almost daily for about two months practicing just running beads on coupons until I got pretty comfortable with it. The biggest challenge was probably learning to feed the filler wire fast enough.
 
Question about welding aircraft tubing? I was once told they were gas welded so the frame did not get magnetized and interfere with the compass. Is this a myth? Sounds like arc welding is now used?
 
rwm said:
Question about welding aircraft tubing? I was once told they were gas welded so the frame did not get magnetized and interfere with the compass. Is this a myth? Sounds like arc welding is now used?
Click to expand...
I don't know about the magnetic issue, but most chrome moly aircraft frames are definitely TIG welded now. Some companies are using MIG, but they are using expensive machines with pulse functions, pre-heating the tubing and then proper annealing afterwards...along with having experienced welders who know what they're doing.

The nice thing about TIG welding is that if minimizes the heat affected zone (HAZ) when done properly. The HAZ is going to lose a certain amount of tensile strength, but with the right choice of filler rod (not 4130) the combination of the parent metal and the filler rod produces a more ductile weld bead so it doesn't crack. Everything I've read about both aircraft and race car crashes and studying the damage says that tubing failures happen right where the tubing meets the HAZ if the welds were done properly. Luckily, tubing for aircraft and race cars is thin enough that they can be TIG welded without the need for annealing afterwards.
 
I still use ocy-acet for some things.
It is a simple and inexpensive way to glue metal together and is rather portable.
I have a horizontal style exhaust pipe on my little Ford 3000 but it hung too low and I kept hitting the muffler on stuff. This fall I cut the exhaust pipe apart and raised it up about 3".
Gas welded it back together.
Looks kinda doohickey but serves my purposes much better now.
 

Attachments

  • 20220805_063229.jpg
    20220805_063229.jpg
    499.4 KB · Views: 18
You must log in or register to reply here.
Back
Top