Gas Welding aluminum

Welding Aluminum with Oxy/Acet DOES NOT work due to the impuritys from the enviornment entering the weld area. Tig or Mig are used specifically for the reason that it has a shield of inert gas such as Helium or Argon surronding the Stinger wich keeps impuritys out of the weld area.

Glenn Hendrix Hendrix Machine & Tool. Inc.

I gas weld aluminum. I use my Henrob torch for this but any gas torch will do. The trick is to keep your gas pressures set low. If you need more heat then change to a larger tip but keep the oxy and acetylene pressures no higher than 4 psi. The other thing that you will need is some flux for your aluminum rods and a good set of special goggles for viewing the weld properly. A few years back everyone was using these cobalt blue goggles but they weren't that good for your eyes. I use goggles that have a gold reflective surface on them. I picked them up at the welding shop and they work really good. Welding aluminum is a bit tricky because the color doesn't change when the metal heats up like steel does. Aluminum is a bit like plastic, one minute its there and then all of a sudden the floor drops out and you have a big hole. The trick is to look for when a skin appears to form on the surface and then push your filler rod in and a way you go. Without the special goggles, you won't be able to see the skin effect. Practice on lots of scrap stuff first before getting into some more serious work. You'll get the hang of it in no time.

---------------------------------- Brent Philion Jan 22, 12:08 am

With the lack of an AC tig machine and an AC inverter appearing to not be in the cards in the near future i"m looking at using Oxy/Acetylene to do the al Welding due to the availability of an OA rig. Mainly i used it for cuttingbut thats not to say its impractical for welding. If i remember right OA has been used for Al welding for a long time specifically in the aviation industry.

Compared to TIG how hard is OA welding of aluminum and are there any special types of requirements for doing it? The only OA welding i would be doing would be on Al and the rest of the time it would be used for heat/cutting

I already have an OA torch (Cheap Harris style kit) but stumbled across a real Victor 100 Handle Might i be better off getting a fresh welding tip for the victor 100? than the giant beast of this harris one?

I will likely never weld larger than 1/4" with most work being smaller than that (1/8" to 1/16")

I would have to disagree with this statement. I have been gas welding aluminum for years.

----------------------------------------- rghendrix Jan 22, 1:36 am

Welding Aluminum with Oxy/Acet DOES NOT work due to the impuritys from the enviornment entering the weld area. Tig or Mig are used specifically for the reason that it has a shield of inert gas such as Helium or Argon surronding the Stinger wich keeps impuritys out of the weld area.

Glenn Hendrix Hendrix Machine & Tool. Inc.

O/A can definitely be used to weld aluminum. It is the first choice of many for sheetmetal on aircraft and various automotive work. I do it routinely with 1/16" and less, prefer TIG for thicker materials. It would take a big tip and a lot of gas to weld 1/4" aluminum, but it certainly can be done. 1/16" to 1/8" is easily done with O/A. Some say that gas welds in thinner metal are more ductile than TIG or MIG and hold up better to subsequent metalworking operations like planishing or further forming.

I don't think welding aluminum is any harder with gas than it is with TIG. With metal 1/16" and less I think it's easier -- but read on.

You can order a videotape on O/A welding of aluminum from

I've not seen it but it's probably a good start. You can also download a short video showing aluminum being gas-welded from It's objective is to sell the Henrob torch. Don't worry about that. Your torch will work fine. The Henrob's performance as a cutting torch is impressive, but others have indicated preference for other torches for welding and the Henrob is a rather pricey torch. Your torch, with appropriately-sized tips, should work fine.

Special requirements: yes! Aluminum welding requires flux. The reverse polarity part of the AC cycle cleans oxides with TIG, flux does it with gas. Some welding stores will have it. The tin man and cut-like-plasma offer it too.

Aluminum flux produces a bright incandescant "flare" that must be blocked in order to see the puddle and to see when a puddle is imminent. Eyewear that blocks that flare is absolutely essential to successful gas welding of aluminum. Regular goggles don't do it, not even close. It's not a matter of "dark" but one of blocking the flare without obscuring the puddle.

Cobalt blue glass was used for many years, but is no longer used because it doesn't block some harmful rays. There's probably some OSHA overkill there for the occasional user, but I've used them and can tell you that there is now a far better choice available.

The TM2000 green dydimium lens, available from the tin man, cut-like-plasma and some other places, is a bit pricey but I'd regard it as the single most important tool to have for gas welding aluminum. It works extremely well. I know of no cheaper alternative that works remotely as well.

Cut-like-plasma does offer an alternative lower cost lens. I've not tried it. HIs video is obviously shot thru the TM2000. If you're serious about learning to weld aluminum with gas, I would strongly encourage you to get a TM2000 filter.

The other indispensible tool is a stainless steel "toothbrush" for scrubbing the metal clean just before welding. They're available at any welding store for well under $2.00 each. If you're familar with TIG welding aluminum you know about those already.

I don't know anything about gas quick-connects. I sure wouldn't use compressed-air quickconnects, don't even think about it! Those either leak or are about to.

Wrong. Dead wrong. Bullshit! Read the Alcoa textbook about aluminum welding , and regard the craft of expert metalworkers in custom aircraft and racecars before you embarrass yourself further.

I do try hard to be civil, but it sorely irritates me when one offering credentials of credibility ( Hendrix Machine & Tool, Inc) posts dead-wrong opinion-posing-as-fact that would misguide an earnest poster asking for guidance.

So much for your credentials and credibility.

BTW, "Stinger" sometimes refers to a stick-welding rod (SMAW process) but not usually to the tungsten electrode in GTAW (TIG) or the wire in GMAW (MIG).

Go to

They have all the info, and supplies, for gas welding aluminum.

Allstate also sells aluminum brazing supplies. They call it Allstate #31

I use Western brand quick disconnects for all my torches. They work very well. I also use their disconnects for my shielding gasses.

The key here is gas velocity, set your pressure for whatever torch you use to provide a low-velocity flame. 4 psi is a pretty good guideline.

My favorite torch is the Meco Midget but I use several others as well. Don't own a Henrob and don't lust after one, though I would if I didn't have plasma for cutting.

4 psi is what Henrob likes for any size tip because it's designed to be so. But there's nothing magic about the pressure. The key is to keep gas velocity down so it doesn't blow the puddle. You can throttle some with the valves on the torch if the torch has good valves.

Good stuff for thin metal, be sure to get the #31 flux as well. It doe not work well (for me) on metal over .062" for some reason. Allstate #31 was developed for HVAC work, joining aluminum tubing in refrigeration systems. It works really well for that. I first saw it demonstrated at an ASHRAE show when it was first introduced. I was amazed.

Tinmantech also offers a similar brazing material, Aerobraze, with companion flux.

I've had varying reports from others on these two materials: some say one works for them while the other doesn't, and conversely. I don't know why. I like them both on thin metal. The Allstate #31 is way lots cheaper, available from Grainger.

The difference in temperature between either of them and welding is less than 100 degrees F. That's a big difference on thin metal, but I find it as easy or easier to weld as to braze on material .050" and thicker. Neither of these materials work well for butt joints; they're better for fillet or lap joints as one might design for brazing. Butt joints and outside corner joints are best done by welding.

I guess they're really different processes. I can cut a preform out of either Allstate #31 or Aerobraze, set it in place with appropriate flux, heat until it wets and flows resulting in a joint that looks just like a silverbrazed joint in brass or steel. Welding aluminum is, well, more like welding, melt and dab while controlling a puddle.

Sorry for dropping in. But this puzzles me a bit. I mostly have my Oxy-regulater at 2.5 bar (36 psi) and the Ace-regulator at 0.5bar (7 psi). That is what I have learned and I only change that setting when I need some wired setting. The kind of flame I want is regulated at the torch. If I want a soft flame, I use a big tip and throttle Oxy and Ace down. If I want a sharp flame, litte tip, oxy fully opened and adjust flame with ace.

And also, I got better results when aluminium welding with a sharp flame. That is because I can keep the puddle smaller. Al tends to have a big (easily huge :-)) puddle because of the good conductivity.

And, while we are at Al welding: Preheat the work. Heat it up until a wooden stick drawn over the part is dropping little sparks. It then has the right temperature for OA-welding.

Heating up (to about 100°C) helps getting better first few inches when MIG-welding Al.

Nick

Whatever works!

I also use the valves on my torch rather than observing any particular regimen re pressure from the regulator. 2.5 bar of oxy would be far too high for my torches, YMMV. Truth told, I pay no attention to the gages at all. I only adjust regulators if I can't get my torch to work right with the valves. I don't recall the last time I adjusted the regulators. I know it's best to relax them when shutting down after use, but I never do it. My bad.

I also sometimes use a wooden splint as a rough temp indicator, but my usual visual cue is the behaviour of the flux. A useful substitute for a wooden splint is a soot smear from a raw acetylene flame. When the soot disappears, you're at about the same temp as the wood stick test.

OK, so do I. More or less.

Nick

On 22 Jan 2006 00:44:26 -0800, with neither quill nor qualm, "Buy_Sell" quickly quoth:

Those $3 stainless steel flux cups are going for a quarter apiece on the kitchen aisle at Wally World (4/$0.97) if anyone's interested. Made in India.

- This product cruelly tested on defenseless furry animals - --------------------------------------------------------

Web App & Database Programming

I find it easier, but then I've got a fair bit of OA experience with steel and I'm a complete numpty with TIG.

One thing I did find is that the aluminium alloy affected things. Magnesium alloys (about 15% Mg) in vehicle or aircraft sheetmetal was no problem to work, purer aluminium didn't give me such good results. Welds seemed structurally OK, but never looked as neat.

Tool up with the right fluxes and go to it for some practice. These things are fairly easily available, but the English flux for 15% Mg is obviously the best stuff - if only for the name "Hari-Kiri No. 2" ! (read the Landrover service manual).

A word on fluxes though - these things are horribly toxic when heated, and their vapours. I'd been using them for years, but I blanched when I found out just what was in them afterwards. Now I'm a _lot_ more careful about ventilation than I used to be.

That is the very reason I have quit reading any posts on electricity. There are even more of those "opinion-posing -as -fact" type posts. It just gives me an ulcer. :-) ...lew...

I was wondering when somebody was going to post this URL.

The "sharp flame point" is a carbonizing flame(?) And aluminum welds need the extra carbon.

One tip (I think from Bud Davisson?) was to place a wooden match stick on the weld line and just weld thru it... Haven't tried that one - but ?

The metals need to be absolutely clean. Tinman recommends a stainless steel brush that is not used for anything else - ever.

and all the rest...

My single biggest reason for OA welding aluminum is the "bird in the hand" theory. I have an OA setup basically used for heating and occasionally cutting and a DC tig setup. Putting 100-200 to touch up the OA kit is a lot more affordable than putting in 1-2 thousand for a replacement tig welder with the 2000 dollar tig welder MAYBE meeting my portability needs. I'm about 50/50 right now with me needing to get myself or the welder near the work or the work being able to come to me

Until I swap out my Miller XMT for a dedicated AC/DC TIG machine i'm sol for trying to tig Al on DC (I tried anyhow despite understanding why it doesnt work and it took me into the corner and beat me and made it crystal clear why and how AC tig works)

your Descriptions though dont really sound any different from What it does on TIG when i had access to an AC/DC machine.

Perhaps i should ask it this way how close is it to tig without the pedal control? I know i needed a Lot of practice to do Al in tig when i was learning but i saw the same conditions I think.

David Bill> Sounds about what I would have said. I found there is a subtle change in

I'm interested in how you do this, since most information on your method is highly lacking on the web. Please, tell me more!

You can weld Al with DC but use the reverse polarity to what you would use for steel. I have never tried it. It does result in much more heat at the torch so you would need to make sure the torch was up to it. I think this would be like running AC TIG with the cleaning setting maxed out.

Quite similar except you can control the heat with the torch distance and attitude, also you can add more rod to the pool briefly to cool it and help bring it under control. You also don't have to worry about dipping the tungsten or hitting it with the rod. I would say that welding Al is only slightly trickier than welding steel. I learned to weld steel with OA and had a few years practice then tried Al and was laying runs under control on Al after about 5 minutes practice. Due to the similar skill between TIG and OA if you are having trouble with TIG then it going to require practice with either process.