You can weld aluminum with oxy/acetylene. The blue inner cone is what you weld with, and the flames/whatever outside of that is the shielding for the weld while it cools.

It actually comes out really nice if you practice it.

The hardest thing about aluminum, is it doesn't change color like steel. It's either a silvery solid, or a silvery soggy mess. I have to use welding crayons that melt at specific temperatures, to know I'm really close to optimal.

others, well, I've seen guys just zip right along with none of that - torch, filler rod, aluminum material, and viola, beautiful welds.

 

What I want to know is where this idea that OA welds are weak came from.

As for welding other materials...

I've had mild success with aluminum, copper, brass, bronze and stainless.

Yesterday, just to see if I still have it, I welded two pennies together. I had to make my own filler first. Anyone else here ever forge wire from a penny? Fun...

 

the person who made that comment probably is better at electrical welding than gas welding. I personally think it's a practice/experience thing. I have a very good friend who owns a two-shift body shop who showed me how to use my Spectrum 375 in place of an oxy/acetylene torch setup for brazing and welding.

If you're not familiar with the Spectrum 375, it's not a welder, but rather a plasma cutter.

Some people just seem to take welding to "Zen" whereas it's an art from and no longer a welding process. My aforementioned buddy's like that, and I'm completely jealous!

 

Frederic,

Spend time with your buddy. Learn everything he knows.

I have a friend at work who's been with the company for 30 years. He spends very little time working on the day-to-day type stuff. Whenever something odd or difficult comes up, they hand him the drawings & he goes off to his corner of the plant. I recently rebuilt his chainsaw & he promised me welding lessons in exchange. Funny part: I'll be teaching him to gas weld. He's never tried it.

 

I used to when we were geographically convienent. Now instead of a 15 minute ride, we're more than 4 hours apart each way. We try though... family obligations and life in general make it difficult. The last time we hung out we just relaxed and shot the breeze for a while.

That's cool though....

 

Actually...here it comes...get ready...that's HOT!

(sorry, couldn't stop myself.)

I just came in from making floorboard patches. I reminded myself of two things about welding with gas.

1) The torch makes a handy dandy rust remover if applied carefully.

2) If you don't go all the way to sound steel when patching floorboards, the handy dandy rust remover gets a little too dandy. (ever try to chase a hole with filler rod & a light touch?)

When I got tired of playing with the rust, I stuck 2 little bits of 1/4" flat bar together in a single pass just to ease the frustration.


He He...

I think we've proven that one or two people still play with fire the old fashioned way.

 

I am not to good with torches but I'm to cheap to buy a mig or tig welder would really like a tig setup but gas welding is slower and it has more waste mig just makes more sense in a production setting if you can use torches then you can probably do any type of other welding the idea that its not as strong comes from people who dont know how to weld with a torch its a lot harder to get the proper penetration with a torch than with any other type of welder I really enjoy the go pedal on a tig no waiting to heat up just stomp it and thn back off

 

What school?
I say he is FOS.

 

Welding with gas teaches a lot more about the behavior of metal like flow points, warpage, annealing, etc than the other systems. Its really incredible to be able to weld, braze and silver solder and body lead with the fading talent of heat control. You can shrink low and high spots in body metal and I could go on.... Its the best if you're trying to do an old style hot rod and use the same techniques. I most recently used a soft flame to melt out the undercoating tar crud that was on the top side of the floorboards of my F-100. I've brazed some brass fitting for the fuel system and done so much more. It really should be everyone's first welder. I actually own a tig and mig but there's no way I could function without a torch setup around the shop.

 

If "gas isn't as strong" why was I allowed by the FAA to O/A weld 4130 tube aircraft frames from scratch back in the 70's?

.....=o&o>.....

 

Beemer, I think you ask the wrong question. Evidently, o/a welding met the engineering specs called for in the application.

All the scoffing at my assertion that o/a is not as strong as electric welds led me to do an extensive search (which I will continue,) on the net regarding relative weld strengths.

I'm not a professional welder or an engineer. But I have done a great deal of fabrication work and welding of various types dating back to the sixties. And I will say this: o/a welding is strong enough for most applications. But a few observations I've made, along with conversations with professional welders and other fabricators led me to believe that o/a welding is not as strong as electric welding.

To use an instance relative to this site, when welding body panels, o/a welding is preferred because you can readily hammer down the beads due to their relative softness. Whereas, if you use a mig weld, you will have to grind the bead off because it is so much harder than the base metal. Not that it's impossible to hammer them flush, but you will likely distort the sheet metal in the process.

In making trailer hitches, the engineering specs call for electric welds and o/a is not an option.

Also, o/a welding puts a lot more heat into the metal being welded which anneals it.

Electric welds are much harder than gas welds. To test this idea, make a gas weld, and then an electric weld in the same material. Then use a sharp punch and hammer to dimple the welds and you will see that it's true.

Or, make two parts out of mild steel. Create two angle irons out of flat stock, one with gas and another of the same dimensions using an electric weld, each one attaining the same penetration. Then put them in a press equipped with a pressure gauge and crush them separately. You will see from the results that the electric weld takes more pressure to crush and it appears that the weld tempers the base metal. The gas welded piece will take less pressure to collapse, and even if the weld holds up (as it should if done well,) the whole part gives and distorts with less pressure because of the annealing effect of the gas weld.

So gas welding has it's place and I think that gas welds may hold up better to vibration in some circumstances, which may have to do with the answer to Beemer's scornful question.

All this is from my personal experience and what others have told me, so I don't claim it is gospel. And I am open to new information. So rather than casting aspersions, please offer up some websites or concrete information to back up contradictory claims. In the meantime, I will keep searching for more info on the subject. I have emailed questions to Hobart and Lincoln both for further information. Thanks.

 

O/A welded 4130 tube will take more bending, vibration and elongation before fractures or a total failure occures, straight from a FAA IA.

.....=o&o>.....

 

I concur, but that is not a measure of ultimate strength, is it. Durable in dealing with vibration because it is annealed and thus less brittle. As I said, each type has it's advantages.

 

OK...

Now I get it...

There seems to be some kind of confusion between strength and hardness.

These two terms are not the same. If you find that the steel is too soft, harden it. If you find that the steel is too hard, soften it.

The harder the steel, the more likeely it is to suffer from stress cracking. Stress cracking leads to catastophic failure.

The reason some electric welds seem much harder than gas welds relates more to the filler material used than to the process. One of the big benefits I find with gas welding is that I can weld many things without using a separate filler material, thus avoiding this issue.

 

Don't forget the wider heat effective area from O/A vs Tig.
There must be 10's of thousands of older general aviation aircraft flying with weaker welds performed with O/A that pass annual inspections, were talking 50-80 year old aircraft.

.....=o&o>.....