Welder choice?

Hello folks, I'm new in this group, but did not find anything relevant in existing posts so I'd like to ask about getting a MIG or
TIG welder. First big question: How much more expensive will it be if I anticipate doing some aluminum welding? In other words I would like to be able to do just some simple steel or iron welding most of the time, but I have a project in mind that will require aluminum welding. Is it worthwhile to get the capability for a single project, or just better off finding someone who can do it for me? The project I have in mind is a light weight trailer to be pulled by a motorcycle, so maybe 1" or 1.5" square tube aluminum is my first guess as to size, but I'll have to do some material strength research before I know for sure. Any thoughts on specific welders? Should I prefer MIG or TIG? Why? I realize I'm being a bit vague here, but I haven't done any welding in about 30 years, and back then a MIG or TIG for the home user was just about unheard of. I was pretty good with arc or torch welding, but I'm way out of practice and don't know enough to ask all the right questions, so any guidance is appreciated.
Bill Ranck Blacksburg, Va.
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snipped-for-privacy@vt.edu wrote:

In order to immediately derail your tread (:, I have to ask why you would use AL. Chrome moly steel will be lighter for a given strength and much easier to weld.

A good new AL TIG welder will set you back over $2000. MIG will be considerably cheaper. I have a Thermal Arc TIG/stick and I like it.

TIG welding AL is bloody hard to learn. I pick up shop skills real fast and am very good with oxy-acc, but I'm still struggling with TIG.

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Fair point, if true. I was assuming strength-to-weight favored aluminum. I haven't done that research, obviously. Though the commercially built trailers seem to use aluminum.

Good to know, and exactly the sort of insight I was hoping for. Thanks.
Bill Ranck Blacksburg, Va.
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snipped-for-privacy@vt.edu wrote:

Find yourself a good used Syncrowave 250, preferably with water cooled TIG torch and cooler and don't look back.
Also TIG is very easy to learn on steel, particularly if you've done O/A or electronics soldering. TIG on AL is more difficult, but gets easier once you get decent at TIG on steel.
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Pete C. wrote:

Yes! I did my first project with the TIG putting together a table for a big surface plate out of 2.25" DOM steel tube, and it came out very nice. I found doing typical steel projects you'd usually do with stick to be MAYBE a little slower with TIG, but FAR, FAR better results, no cleanup, and I could even weld inside! I have to work totally blind with stick, and always burn big holes in everything. A total mess. (I did have a horrible buzz-box welder, glass filter hood, all the worst stuff.) Once I did my first TIG weld in steel, with an auto-dark hood, I sold the buzz-box! Never again.
Stick is a LOT cheaper, no tungstens, no torch accessories, and especially no Argon! But, the flux smoke REALLY gets to me, so I hated to do stick welding. Now, I jump at the chance to do some TIG welding. I have done stainless, pure copper and aluminum alloy, as well as mild steel. Oh, note some aluminum alloys are not weldable.
With steel, you can use the color of the weld area to control temperature. Mild red is good, yellow is too hot and you are getting close to having it go Blop! on the floor. With aluminum, it will go blop before the first sign of color appears. If possible, having a piece of copper bar or even steel clamped below the aluminum can prevent a melt-through. So, you have to get up close and observe the mirror-like surface when the aluminum starts to melt.
Jon
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That's a question I've been wondering about for a while. My choices are either in the basement of my house or in my wooden shed (wood floor and all). The wife would be really pissed if I burned down the shed OR stunk up the house.
Is it really OK to TIG indoors?
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pmv wrote:

You nearly have to. If you have even a slight draft, it blows your shield gas away. At the price of Argon these days, I want to get by with the MINIMUM flow I can.
It is a bit messy to TIG anything galvanized, otherwise I haven't had any problem with it.
Jon
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wrote:

Do the math. Welding produces smoke.
Steve
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SteveB wrote:

If you are TIG welding AL and you've done proper surface prep, there's hardly anything to create smoke.
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That's what I thought. Is that also true with steel?
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Jon Elson wrote:

An auto-dark hood is a huge help for hobby welders, both since we don't get enough practice at helmet flipping, and since we tend to have a lot of short welds with a lot of setup in between. A good TIG machine is also an excellent stick machine so you get 2-in-1. I particularly like the "arc control" adjustment on my Syncrowave which helps prevent sticking the stick on the rare occasion I do stick.

Yes, having some material for backup bars is very helpful. I recall Ernie indicating *not* to use a copper backup bar when welding AL. Something with contamination of the weld I think, ceramic is ok.
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wrote:

Haven't done it myself, but the hot ticket for MIG on Aluminum is supposed to be a spoolgun...
That way you don't have to worry about the aluminum wire kinking in that 20' - 30' of liner from the welder out to the gun - it goes straight from the bulk roll, to the feed rollers, then straight out to the nozzle tip. Or it makes one turn if you use a curved tip to get around an obstruction.

Well, you can do a LOT better for stick than a tombstone buzz-box. A lot of the old Miller gear does stick beautifully, very controllable. And you can do much heavier work in one pass, especially with an engine drive so you aren't worrried about blowing the main fuse.
Big problem with stick is the huge learning curve, where you'll be making a LOT of hole and a LOT of cold dauber welds till you get it all figured out and build a touch. And it's even worse if you are welding a thin tab to a thick beam, or vice versa - getting the penetration divided right is nasty.
Whereas you can pick up MIG or fluxcore wire-feed a LOT faster, and be making good structural welds in a few hours of practice.

You can buy or build a fume extractor for welding, to get the smoke out of your face. Simple as a boat bilge blower or a large muffin fan, and a length of aluminum foil dryer hose for the inlet.
You can use the vinyl flex hose for the exhaust end of the fan, getting the fumes out of the garage, but the molten dingleberries will light vinyl duct on fire at the weld end. With the aluminum foil flex on the suction side the spatter might melt a hole, but that's it.
--<< Bruce >>--
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That is interesting. I used to do assembly line soldering on MIL-Spec electronic equipment, so electronics soldering I can do in my sleep. In fact I think that's why I picked up stick welding fairly quickly, a molten puddle is a molten puddle to some extent, although I know aluminum has very different melt characteristics.
Bill Ranck Blacksburg, Va.
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snipped-for-privacy@vt.edu wrote:

TIG is very much closer to electronics soldering than stick, with no sparks, smoke or spatter so you can get in real close to see what you're doing, and heating with a torch in one hand while adding filler with the other.
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Jim Stewart wrote:

Maybe. I have finally gotten to where I can do it with predictable results. it took a while, and there was a lot of scrap. I had a friend over who had never even SEEN a TIG welder. I set up some scraps from a recent project and made one weld to show him the general technique. Then he tried it, did a pretty passable first weld, and then proceeded to show me up totally on his second piece, producing a weld as good as my best. He has done a fair bit of stick welding in the past.
I have to admit I have a really GOOD TIG welder, a Lincoln Square-Wave TIG 300, with a water-cooled torch. I think this does make a difference, too.
Jon
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Jon Elson wrote:

It is vastly easier to learn on a good machine. I good weldor can get good results from a crap machine since they know how to compensate for all it's faults. When learning it's much easier to only have to compensate for your faults.
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Jon Elson wrote:

I'll certainly concede that some people might be able to pick it up quickly. OTOH, to do thin AL sheet requires another level of physical and hand- eye coordination far above most shop skills. I'd put it right up there with learning to land an airplane.
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wrote:

Ive done a bit of welding myself over the years. Stick weld like a pro. Mig weld like a regular... Fumblefuck around on TIG. It sticks..every other weld often looks nice....but its HARD for me.
Ive got some nice welders...Esab SquareWave 200, Airco 300 SquareWave, Synco350....just the machines for TIGing..and thats the best I can do. Ive got neighborhood rug rats that Ive worked with for an hour, that can TIG like pros now. But..its still Hard for me. Some folks are better on one method than others. Shrug..you just have to find out what your style is.
If you can do all 3..you are Da Man
Gunner, tickled to get 2 out of 3
"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.
Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner
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Ditto here. I can x ray on stick and MIG, but can hardly put two pieces together with TIG. I can do stainless so it sticks, and it looks decent. Never got the hang of AL. But give me some 6010 and 7018 and tell me what you need done. Everyone is good at something, that's the way of the world.
Steve
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On Wed, 01 Apr 2009 13:20:26 -0700, Jim Stewart

Indeed. And it wont rot as fast as Aluminum
Gunner
"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.
Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner
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