Aluminum MYTHS and misunderstandings.

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Hello, everyone.  I have been looking into buying a new welding machine and I'm confused as to what I will need.  You see my father has been a rig welder/pipe fitter/etc.. for 20+ years and he can't seem to give me a straight answer on what type of machine I will need to get.  He has never welded aluminum and he is convinced you have to have some super duper - ultra- high frequency- multi phasic - high amp machine in order to weld aluminum, ordinary "steel" designed machines wont do it....  All of his buddies seem to concurr with him on this, but none of them have ever welded aluminum either.  SO,  can you guys please tell me if there is a difference in machine designed for aluminum versus any other machine out there?I would prefer a mig machine or mig/tig combo.  I have experience with steel with both stick and mig but never tig, and obviously never aluminum.  I will be using it 4hrs/wk on 1/4 aluminum mostly.Somebody help me disprove the SCARY ALUMINUM myths!!!  LOLWhat specs are a must?  What machines will not weld aluminum and why not?  What is this high frequency all about? and what is the difference in phases?  What amp machine is neccessary?
Reply:Short answer is either MIG with a spoolgun or TIG will let you weld aluminum.  What will you be welding.  Something like bicycle frames and you probably want to lean towards TIG.  Aluminum trailers or something where you are laying down a lot of bead and you probably are leaning towards MIG.
Reply:Thanks!  But does anybody have the LONG answer?  I really would like to learn about all of this...
Reply:I will be welding both trailers and motorcycle parts.  MIG is what I am looking for, maybe a mig/tig combo though.  But details, amps, phase, frequencies, Specs this is the info I really would like to learn about.  What prevents certain machine from welding aluminum most of all?  Can ANY MIG machine weld aluminum?
Reply:An AC/DC tig machine will weld aluminum quite well. You use the AC for welding aluminum, and you need a High frequency unit built in. Most any ac/dc tig welder built in the last 30 years has the hi-freq. Tig welding is the most elegant way to weld aluminum- takes some practice, but once you learn it you can make strong, good looking welds in aluminum. Aluminum sucks up the heat, and so to weld very thick stuff, you need a fair amount of amps. Straight argon for sheilding gas. I have a Miller Syncrowave 250, which actually  puts out closer to 300 amps on tig, and I have run into cases where it just doesnt have the power- we had to preheat with a rosebud a bunch of 3/4" to 1" aluminum brackets we made once. As far as mig- there are 3 ways to go. If you only do it once in a while, and you are patient as a saint, you can use a regular mig machine- you need to hold the gun straight out from the machine, no kinks or curves in the hose, and you probably will want a brand new plastic liner, and also probably new drive rolls, both of which you never use on steel. You will still get the occasional birdsnest, but it works, and it is the cheapest way.Next step up is a spoolgun of some type- a gun that takes a 1lb spool of aluminum wire, and has its own motor in the handle. Most, but not all mig machines can take one of these, and many freestanding power supplies can have one plugged in as well.I have used one of these a lot, and it certainly works, but can get frustrating sometimes as well- burnback, leading to clogged tips and birdsnests seem to happen if you arent perfect in every way.Then, the ultimate aluminum mig setup, in my opinion, is a push pull unit- this has a full size wire feeder, with a spool of aluminum, and a second motor in the gun, so it both pushes and pulls the aluminum wire. Cobramatic is the oldest and best known of these, but Miller makes these too, and I am sure there are other ones out there. This is an expensive unit, and does not include a power supply- so you need a power supply- either a constant voltage mig unit, or an inverter, or a gas drive unit like a trailblazer. But for mig welding aluminum all day long, this is the setup you want. Again, the more amps the better. If you are gonna do anything over 1/4", I would go for 200- 300 amps. Commercial units as big as 500 amps are not uncommon, for heavy stuff like aluminum boats or dump truck beds.I have a tig welder, a spoolgun, and a push pull, and whenever possible I tig. Mig welding aluminum is smoky, spattery, loud, and messy. I do it when I need cheap, fast welds, and the piece doesnt have to look real pretty. My weld bead looks fine, but the whole area around it gets somewhat messy. With tig, when  you finish the bead, you have a real purty finished product. Plus it is quiet and fun.
Reply:So tig is the way to go!  Considering I don't have 2-3000 to drop on a machine.  Thanks.  As far as a power supply goes, would I be able to find one that would plug into most household heavy duty sockets? What is it 220 or 240? something like that?  Or will I have to use a generator?  thing is I have easily annoyed neighbors and generator can get pretty noisy after a while.Do you have any low cost tigs you'd recommend?  Which one's should I stay away from?  I'd like a machine that could weld both aluminum and steel though, how is tig for steel?  I've never used tig...
Reply:Welding quarter inch material with a TIG torch is a slow process.  I think a spool gun would be the correct choice.  You will need a larger power source running on at least single phase 220.  The shop I am in uses a 300 amp Miller constant voltage power source that drives a regular wire feeder for steel and a push pull feeder unit for aluminum.  We switch connections between feeders and the type of gas and we are good to go.  A spool gun might be more economical in your case rather than a push pull gun.
Reply:would something like that 300 amp miller CV that you have also power a tig torch for small projects if need be?
Reply:Isn't single phase 220 what washers and dryers in most houses use?  Which machines will be able to use this type of power?
Reply:PS, great info here so far!  Thanks for all of your help!
Reply:there are machines that will change from TIG to CV ( wire feed) but they are really expensive.  We weld down to 1/8th tubing for walkways etc.  If you are going to be regularly welding intricate parts then you will have to go to TIG and sacrifice speed.  Single pahase 220 is exactly what dryer circuits are.   40 amp breaker will get you around 250 amp welding current approximately.  You will need a power supply to give you AC plus a high frequency feature.  Newer units use lift start instead.  When you touch then lift the tungsten off the surface the arc starts.  This still hasn't addressed welding steel althoug slow you also could weld steel with TIG.
Reply:http://cgi.ebay.com/ws/eBayISAPI.dll...501406645&rd=1would this one be something like the one you're using?  I think something like this might be good for me huh?  Wouldn'e I be able to hook-up a aluminum spool or push pull to this and a tig torch?
Reply:My bet is this machine will be bid up MUCH higher.  It has the power for all your wire feed requirements.  For aluminum TIG you will need a high frequency unit for starting.  I am not sure what is available.  It certainly will do regular electrode welding and if you don't mind scratch starting with TIG you would not need a high frequency unit.  Sctatch start on aluminum is not a good practice.
Reply:i see that that welder, even though it looks like a newer model, it still doesn't have the High FREQ needed to weld aluminum, or will it just not TIG aluminum due to the lack of high frequency?  will it still weld via mig or stick without the High Freq?
Reply:Look around on Miller and Lincoln websties for info.  The high frequency is a small high voltage current running on top of your welding current.  As you bring the TIG torch near the parent metal it strikes up an arc.   You need either the newer lift start feature or the high frequency to start on Aluminum.   Aluminum TIG welding outfits are relatively expensive compared to TIG for steels.
Reply:Try this site for information.  You can download informations sheets on each process.http://www.millerwelds.com/products/basics_hints/
Reply:If I was you I would go to a real welding supply store, preferably one that sold both Miller and Lincoln. Most good ones do. Then ask them to show you the different models, and explain what they do- and prices. Then, get both catalogs, take em home, and study. Preferably also buy a decent book, like maybe Richard Finch's book, "Welders Handbook".This is a real complicated subject- and it is definitely one where the old- "Good, Fast, or Cheap- Pick one and a half of them" rule applies. There are cheap power supplies which will run spool guns or push pulls, but spool guns and push pulls arent cheap. Tig is never cheap. There are many levels of tig machine, from a basic DC welder with a scratch start tig torch- wont weld aluminum- to a $6000 Miller Aerowave.There are a couple of machines that will indeed do everything, like a dynasty, which can do tig and mig, but it sure isnt cheap.Until you have actually done some tig welding, in both aluminum and steel, and some aluminum mig welding, I wouldnt spend a bunch on a machine. Since I do a lot of welding, I can justify having as much invested in a variety of welders as a new car costs. But you probably cant. So you should figure out exactly what your own compromises are- how much are you willing to spend for what features, and what dont you need. The only way to really know that it to actually weld with the machines- consider a night class at community college.
Reply:Also, high frequency isn't what makes a machine capable of welding aluminum.  HF is used only to start or stabilize the arc.  Tig machines for welding aluminum are AC machines, the better ones are square wave.  An AC sine wave machine will weld aluminum, but the task becomes more of a challenge.  Always better to go without a machine for a little while longer, than to spend your money on a machine that wont allow you to do the job.  Expect to pay about $2- 3K on a good TIG machine that can handle aluminum, and square wave machines make the job quite a bit more enjoyable.  Inverters are the most flexible, but they are also the most expensive- $3k plus for an AC/DC 200 amp model like the Lincoln V205.  But that one only weighs 33 pounds, compared to 3-400 pounds for a conventional tranformer based welder, and you get frequency control, as well as TRUE square wave, current balance, etc.Whats a day without flippin' like a trout?
Reply:Since I do very little aluminum welding I have the economy set up.  There's my Dialarc two fifty, the old Miller high frequency box I got in a trade many years ago, and a two hundred and fifty amp air cooled scratch start torch.The most expensive component for me was the torch.  I already had a tank full of argon for mig.  Everything else except for the high freq box has another purpose.So yes, you can get by on the cheap.  If you already have a good base of equipment and experience.  Otherwise the best way to do it is to over buy, buy bigger and more than you think you'll need.  It is human nature to under buy, and under buy, and under buy.  Then one day you wake up and you've spent three to four prices and you still don't have what you want.life is good