If you have access to 220/240 volt power, I would recommend getting a welder that runs on that. Mine is a dual voltage welder and I was running it on 120 volts when I built that aluminum frame. It worked fine for everything but the head tube joints. It was difficult to get enough heat into the 4mm thick head tube with the reduced amperage from running it on 120 volts.

You want a 200 amp AC/DC inverter TIG welder for welding aluminum. Most of them are going to be in the $600 plus range, anything less will probably be a DC only machine. I have an older version of this welder and it has served me well for all of my welding of steel, stainless steel and aluminum. https://ahpwelds.com/products/alphatig-225 Keep in mind that you will also need a tank of Argon gas for shielding.

I also have an AHP Alpha-TIG, a 201XD, like @dsaul's it's an older version of the one he linked to.
Like anything Chinese, it will be slightly risky, if you get a bad one, not sure how good the support will be. But at about 1/4 the cost of a US-made welder, you can replace it with a new one a few times and still be money ahead.

Mine has been reliable except for the foot pedal that died after about 4 hours of use. For one project that needed to be done with no pedal, I welded with only the torch-mounted trigger (included in the box with the welder) but you can't adjust the amperage during a weld, a huge downside. I puchased a US-made pedal and now this is a capable and versatile welder for not much $$.

I made just one 4" long weld on scrap aluminum just to test the AC on it when new, but other than that I've done no Al welding to speak of. But the AHP has gotten good reviews from people that do weld Al.

About the 220V power, you may not know it but your house already has it (all US houses do). If you don't have a convenient outlet, maybe you have a clothes dryer that's electric? I actually made myself an extension cord to go from my dryer outlet to where I do my welding, as a stop-gap until I could get a 220 V circuit added in the shop. An electric stove is anothe rplace tou may have a 220 V plug.

Not only is the welding amps limited when running on 110, I think it stresses the internals more. You know the amperage is doubled when you run it on 110, right? Oversimplifying a bit, but it's amps that kill electronic components. Don't be afraid of the higher voltage, it's cutting your amps in half and that's all good. 220 (240) V is the standard household current for everything, wall outlets etc., in many places outside the US and that has advantages, to where people in those places look down on our 110 V standard as backwards.

One caveat about running it off a dryer plug: those are typicallt 30 A circuits, and the AHP wants to be on a 40 A. According to AHP tech support when I asked, that's OK if you limit the welding amps to 160A. He said if you weld at 200 A on a 30A 220V circuit, it won't trip the breaker, but it can damage the welder internals by "starving" them. Never heard of that (is that a real thing?), but I did limit my weld amps to 160 while I was on the dryer plug.

Then I added two 220 V circuits to my shop myself, and I'm no electrician, learned how on Youtube. No deaths to report yet (fingers crossed!) Just size the conductors (wire gauge) appropriately for the breaker size, or one gauge heavier as I did — copper is expensive, but cheaper than fires. Since my service panel was full, no room for more breakers, I had to replace some of the existing 110 breakers with duplex, where two breakers fit in one slot. That was surprisingly easy, requires just one screwdriver. One trip to the store to buy breakers, and an hour later I had room for my 220 V breakers.

For fumes, you need to wear a respirator ! A 3M twin-cartridge half-face mask with the correct filters will protect your lungs.


To your question, if you haven't welded aluminium before (that's how we spell it) with an AC tig, be aware that much higher current settings are needed cf. steel, as aluminium's heat conductivity is far higher. You can compensate to a degree with pre-heating the parts to be welded but that is going to be a pita with a bicycle frame I'm guessing.


If the material you are welding is around 4mm thick, I second the above suggestion of a 200 A machine. I think that will be enough, but not by much in my experience. It gets really expensive if you go to a much higher current machine though as you then start to need three phase power supplies and water-cooled torches and water coolers.


I see that you are in the US. Unless you have $$$ to spend on a good European machine (like CEA), or of course like some of those good American machines you have, I would recommend one of the best Chinese machines there is - the Unimig (forget the "mig" part, that's just the company's name, they make all types of electric welders) - apparently sold in North America under the Jasic and Razorweld brand names. They have a really nice 200 A ac/dc tig that is raved about over ("down") here.


That's Aussie dollar pricing so yours will be less. Also that's full retail so better deals are available. And finally, I just saw a message on Unimig's web-site that "they are launching in the US with local operations" so perhaps the Unimig brand is coming to the US in a much bigger way. Maybe you'll get some introductory deals ?


https://unimig.com.au/product/razor-...-ac-dc-welder/

To the OP: Welding specialty aluminum alloys is challenging for a beginner. Frankly, it is easier to weld titanium and get good results than to weld thin-walled aluminum—just a fyi. The natural progression, in terms of complexity and skill level, is: lug brazing, fillet brazing, steel TIG welding, titanium TIG welding, stainless TIG welding, and aluminum TIG welding.

I am questioning your decision to start with the most challenging.

I absolutely love this quote by Tanya Zavasta, "Tell me it can't be done, and I'll show exactly how to do it"

Or "People who say it cannot be done should not interrupt those who are doing it". -anonymous
Don't believe anyone who attributes that to George Bernard Shaw or Confucious, neither one said or wrote that, as far as scholars can find.

It's probably just a mis-remembered attempt at quoting the humor magazine “Puck” from December 1902:
"Things move along so rapidly nowadays that people saying: “It can’t be done,” are always being interrupted by somebody doing it."

Back in the early 80's one of my friends asked me why bicycle frames were not TIG welded together. I replied that it must not be possible or someone would have been doing it. I did know that KHS (I think) made a TIG welded tandem frame but I assumed that was only possible because a tandem of that era used thick walled tubing.

In 1992 I took a TI welding class at UBI. It was the first one they offered with Gary Helfrich (one of the founders of Merlin) instructing. I''ve TiGed a few titanium and steel frames but making them is not really what I am interested in doing.

USA were the pioneers of TIG bicycle frames. We first started seeing them in the UK in the 90s from brands like Muddy Fox and Ridgeback, who were getting them made out of Cromoly in Taiwan, copying the early US MTBs. Domestic production of Raleighs, Falcons, Claude Butlers etc. in UK however continued to use lugs, because that's just what our bike factories had always done. And you can't weld Reynolds 531 anyway.

Reynolds came out with their main weldable tubes (631 and 853) in 1996, by which time most of the UK mass-produced industry was well in decline anyway.

I don't know where you got that list from, but it's wrong.

Personal experience. What do you think I got out of order? Thin wall aluminum was the most challenging for me, there are minimal visual clues and being such a heat absorbent material blow through happens without warning, very susceptible to warping and distortion and machine setup is very difficult.

When people say they they love a challenge and move ahead when experienced others advise caution, although it sounds cool and brave, frankly it’s silly will result in failure or a huge waist of money and time at the least.

Lugged construction takes four times as long as tig welding, and involves a much wider skill set. Aluminum might be hard, but it is commonly accomplished with autofeeding pulsed welders. Or even MIG. Making a decent looking Ti weld may or not be hard, but actually making one that won't fail a year later is clearly difficult.

But if your point is that the OP is overestimating their ability to acquire the skills and execute a thin-walled frameset in little time - I agree.

I book marked the UniMig USA launching site. In the mean time I will check out all of the tubing suppliers mentioned above and buy tubing. Thanks for those.

All of these things have different learning curves. TIG is cheap and fast once you can do it (that's why lots of mass-produced bikes use it) but it does take a bit of practice, and aluminium TIG is generally considered harder than steel (although I haven't tried it). But I don't think the OP should be discouraged-- just be prepared to put in the practice that's necessary.

Gary H might be the biggest reason steel lightweights started to be TIG welded. Of course Teledyne Titan and the other Ti frames like Flema were TIG welded way earlier, but in steel, TIG was restricted to BMX. It was widely believed that TIG was inappropriate somehow for thin steel. Gary knew better, he was a skilled welder working for Chris Chance but not welding frames, until he convinced Chris to try one. Chris agreed and AFAIK that was the first widely-available welded steel frame. Chris of course went on to make the popular Fat Chance bikes that were all welded. MTBs soon followed, with road not too far behind.

That may be because the small ones didn't work very well until sometime in the 1970s. That improvement may have taken awhile to trickle down to bike builders.

You should try it. The machine setup is the difficult part of AC TIG welding. DC is easy, because you just set the amps and weld. AC requires the correct AC balance setting (about 30% electrode positive or 70% electrode negative, depending on how your machine shows that value) , in order to get the right cleaning action and prevent your electrode from melting. Once you get that right, I found aluminum welding to be easier than thin walled chromoly steel. Everything happens slower with aluminum, so you have more time to see what is happening with the toes of the weld puddle and more time to feed the filler metal and advance it in your fingers. I'm not necessarily recommending building aluminum bicycle frames, but you should get some aluminum and practice. I think you will pick it up pretty quickly.

One thing to note, and I think it is the main reason for people having issues with the puddle suddenly melting away, is you need to physically remove the oxide layer on the surface of the aluminum just prior to welding. The oxide layer develops pretty quickly and its melting temperature is much higher than the aluminum. If you try to weld without removing the oxide layer, it will melt the aluminum under the surface before the oxide layer melts and then the whole mess just falls out when the oxide layer breaks. I prep my material by abrading it with scotch brite just before welding it.

Thanks for the tips! I am quite tempted to try it just for fun, but it would mean buying a new machine. Although I guess if I had one I'd soon think of things to make out of aluminium Actually it might be quite good for racks (I currently use stainless tube and TIG braze it).

Desaul, very good tip. Good cleaning and proper machine settings per your work, very simple. Thanks

Lugged construction on steel is by far the easiest, requires the least skill, is the most forgiving, and requires minimal equipment. That is why most homebuilders and small shops start with that process, and so do amateur framebuilding courses. Production lugged assembly is as fast as, if not faster than, TIG; however, the end product is heavier, and the material cost is higher. Fillet brazing is similar in difficulty, allows for cleanup afterwards, and requires minimal equipment.

TIG welding is a skill which takes more time to learn, and setup is more challenging; equipment can get expensive. Steel TIG is fairly straightforward and not very sensitive to contamination, a great place to learn or produce in volume. Titanium prepping to prevent contamination is an issue, but it is minimized in dedicated facilities or small builders; however, it is the "Goldilocks" material for TIG welding and can make an amateur look like a professional. The ease of taking a second pass allows for a very cosmetically appealing weld as well. Lastly, stainless steel is also very sensitive to contamination, does not absorb heat well, and is usually supplied in very thin thicknesses, making it very challenging.

Furthermore, traditional lugged construction inherently stifled innovation in frames. Because builders were bound by standardized tubing and lug angles, experimentation with geometry and tube diameters was severely restricted. TIG welding changed everything, offering unprecedented design flexibility. Once TIG-specific materials, such as tubing with shorter butts, hit the market, the shift became irreversible. This technical evolution was accelerated by market economics: as high-end TIG equipment transitioned from prohibitively expensive to accessible for well-capitalized, artisanal builders, the barrier to entry collapsed. Ultimately, the road market was primed for disruption. For decades, thousands of builders had offered virtually identical products differentiated only by branding. In hindsight, the pantographing era was a desperate attempt to manufacture perceived value and distinction in a fundamentally homogeneous market.
​​​​​​​

You could do all of that with fillet brazing, and always could.

Lugs are only 'easy' if you are building a medium size frame that requires no lug modification for angles.

Thus the early Ritchey and others were fillet. Problem with that system is finishing is time consuming and slow.

Finishing aluminum welds like they used to is also a lot of work. But as soon as you decide you don't need to finish welds or fillets you don't have to spend that time.

I'll add a couple of comments (while I wait for the Sabers/Montreal OT to start):

Early Cannondales had pretty ugly welds (besides their alignment and distortion issues) but their lightness and immediate stiff/response won over rather quickly. In short time welded frames began to be "graded" by their weld beads (excepting the BMX world who were already there) and weld adherence acceptability evolved.

Back in the Chicago manufacturing days Schwinn used a lot of lead... Easy to apply to a still hot joint and later smooth down.

From what i've understood the "stack of dimes" AL weld beads, from the many mass produced brands, show a lack of best fusion. Still the size of the bead and wall thickness is enough to support the stresses... long enough for the warranty department to be happy.

I know that good fillet brazers can complete a joint and have very little clean up time to get to smooth clean surfaces (wish I was in that club). In mass production tricks can be done to further reduce the human aspect to the actual brazing moments, "brass" preforms and filler doped fluxes have been around for a long time. The classic (if early 1980s can be called that) Peugeots are a nice example of what smart brazing design can result in. (Sabers just lost, oh well there's always next year). Andy.

Old Kleins, Schwinn PDGs and Cannondales between maybe '87 sometime in the 2000s had the welds ground down to where there wasn't anything to judge the quality of, except that there aren't any voids. I stripped my 89 'dale down and polished it - was like the most carefully blended fillet brazing. I can only imagine how many beads that took in some areas to end up with such smooth transitions.



This guy did pretty much what I did to a similar vintage Cannondale:
https://www.team-bhp.com/forum/bicyc...iss-shiny.html

It makes you wonder if these bikes could have been lighter had they featured bead welds, but this was the design and Cannondale produced sub 3 pound frames with this method.

My point was that the fat beads of unground aluminum weld could be a model for lower cost fillet brazing that isn't finished - just like TIG usually isn't finished these days. Just clean and paint it:


Of course, Peugeot internally brazed joints would probably be easier than either fillets or TIG.