Very New with lots of questions

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Hey All,My name is Rick and i'm very interested in welding and fabricating.  My main focus is around motorcycles primarily for welding subframes and small aluminum parts.  Most of the aluminum i'll be working with is T6 6061 Aluminum.  Here are some photos of what I want to weld.[IMG][/IMG]I'll also be welding on the frame as well which some portions are cast.  I did take a short 9 hour night course on welding and briefly went over GAS, MIG and TIG welding.  Unforutnately the only thing I got to use was the MIG machine.  That was fun and now I'm hooked.  The only thing is that everyone told me that I should just go out and buy a TIG machine.  The only thing is that i can't afford a TIG right now.  The instructor also mentioned that I should really master GAS welding before moving onto TIG.  Now i've seen alot of machines and set ups.  The only thing is that there is so much out there that it just gets confusing and people get very defensive if you mention a non-american made machine or set up.  I not here to piss anyone off but money is a big issue, as important as safety.  I'm sure my wife isn't going to be happy if I blow up our garage.So here are my questions:1. Can I weld Aluminum with an Oxy/Acetylene?2. If I do get a TIG what machine should I get?  I only have access to 110V, and like i said I'm not welding huge heavy parts of steel, just aluminum but I don't want my welds to be comprimised.3. What brands should I be looking at for Oxy/Acetylene and TIG machines.Please help, I'm just looking for some information to get me started but in the right direction.  Thanks all,Rick
Reply:Hmm... doc I want an operation, but its kind of pricey, can you find me a 3rd world vet assistant that will work cheaper? Oh and all that high tech medical gear is a bit expensive, can you make do with an exact-o, visegrips and some Listerine? In all honesty thats basically what you just asked. (even though you didn't understand it when you asked)Ok I'm done with the sarcasm, Sorry. I said that to get a point across, not be mean. It's not about import vs American, it's about spending whats required. Given the above it's possible everything would be fine. Do you want to gamble with a life?Can you weld Alum with OA? Yes, but it's not easy.Can you weld it with TIG? Yes but it's not easy.Can you get a Tig machine that will weld Alum and run on 110V? Yes but it's very expensive.To TIG Alum you need a machine that will weld AC tig. To do this at 110v you need an inverter unit like a Miller Dynasty 200. Cost over $4K.Alum is much more difficult to weld than steel. Alum dissipates heat faster than steel so it requires much more power than steel. Thats why alum is used for things like heat sinks. Alum also acts differently than steel and it looks different. Your best bet is to learn to weld steel 1st, THEN  do alum. Finding someone who is good at OA alum will be tough as it's not really the process used for that. Mig may work also, but again you need more power than is usually found in 110v units, so you are back to 220v, and with the machine, the spool gun, gas required, it still adds up to almost what a 220v AC tig would cost.This is not a cheap hobby. To do Alum requires a decent machine capable of AC and even 220v units ain't cheap. You want to work on parts that when they fail can seriously injure someone, if you are talking about bikes. Even if its just a bracket, if you don't do it right you can weaken the original part and cause it to fail causing injury. You also need to make good welds, not just stick metal together.Also not all light weight metals are alum, and not all alloys are weldable, and some alloys are more difficult to weld than others. Tracking down just what the alloy is in the bike may be a bit difficult also as that info may not be easily available. Also was the part heat treated for strength? There are so many questions that need good answers that you can't give with out a lot of training.Best suggestion, take your money and invest it in several good welding classes. Learn with their machines. The school is more likely to have better machines than you can buy for quite a while. having some one watch you and tell you what you are doing wrong is the best way to learn. Learn on steel and get it down very well, THEN try alum. You won't be out anything this way. The cost of the class will be offset by the use of the machine, the materials, the consumables like gas, not to mention the instruction. You might find that you can use their stuff to do the projects you want to do, or maybe your instructor will help you do what you want and use it as a demo.If you balk at spending the money to learn to do it right, don't spend the money on a machine or OA. Spend the money to have someone do it for you who knows what they are doing. If you are looking for a fun hobby, and want to learn, then start at the beginning and work slowly towards a goal, but expect to spend time and money doing it.Good luck.Last edited by DSW; 06-29-2009 at 07:27 PM.
Reply:TIG is what you need, OA will not work.Aluminum takes higher current than steel or stainless steel because the thermal conductivity is so high, so ideally you'll want an AC/DC inverter capable of about 150 amps minimum, 200 or 250 amps would be best, and this means you need 240 volts minimum for the power supply.The higher currents used for aluminum lead to the need for a water cooled torch and a recirculation water cooler as well.AC is best for aluminum since the electrode positive portion of the AC wave provides a cleaning action removing surface oxide as you weld.  Good older transformer power supplies and the new inverter welders have an AC balance control that allows you to dial in a high percentage of electrode negative, like 80%, to achieve deeper penetration at the limited amperage, while having some oxide cleaning action of the electrode positive.The new inverter power supplies also allow the use of a sharpened tungsten electrode with a more stable constricted arc compared to the melted ball end tungsten used with the transformer machine.Newer inverters also have adjustable AC frequency that can provide a more stable and constricted arc at a higher frequency like 150 Hz versus 60 Hz of a transformer.Aluminum is challenging to TIG for precision motorcycle components you are talking about, so if you decide to get into this, your life will be much easier with a good modern inverter versus an vintage transformer.Lincoln, Miller, Thermal Arc, or ESAB, all have fine machines, and just guessing, you'll need about $3000 to get started.
Reply:Pulser,  With all do respect, you dont know what your talking about with OF welding.  Every bit of aluminum prior to about 1950 was welded with either a OF torch, Atomic Hydrogen, Carbon Arc, Arc, or resistance. And Tig wasnt even that common until the late 1960's. So that means all race cars prior to 1950 had gas welded aluminum in their bodies, fuel tanks, castings, etc. All the motorcycles were the same. Fuel tanks from BSA's were gas welded up through the 1970's. All the aircraft in WW2, the jet age through the korean war. Gas welding is still done daily. Boeing used it through the 1990's until Osha had a fit with the fluxes. In the aircraft world its common, and many times accepted as being a supperior joining method for things like fuel tanks for obvious reasons.  Everything from delicate little parts through railroad tankers were gas welded aluminum. Now if you are not capable of OF welding aluminum, thats fine, but just admit it and keep your un-informed opinion to yourself. Sorry if I seem harsh, but durring my welding classes I have to put up with uneducated "weldors" that think they know the world , which obviously didnt exist before Tig  And yes I tig weld, and love my inverters!
Reply:One of the major difficulties with aluminum welding is the puddle looks different from a steel puddle. The aluminum puddle will appear shiny and freezes fast. Aluminum melts at about 1250’F and can be easily overheated by the arc, making it easy to burn through, may disappear-vaporize. Aluminum is a more active metal then iron and often requires back shielding gas. You need a light hand to get a good weld=practice, practice, practice practice.
Reply:I agree with DSW. Properly welding anything is difficult and expensive. Aluminum is more of both. You don't get to just decide "I want to weld aluminum", buy a $500 welder, with no experience, and start welding aluminum.I paid almost $3000 for my TIG setup, many years ago, thinking "I want to weld aluminum". It still kicked my a$$. Self taught is really hard. And that's with the proper equipment.9-11-2001......We Will Never ForgetRetired desk jockey. Hobby weldor with a little training. Craftsman O/A---Flat, Vert, Ovhd, Horz. Miller Syncrowave 250
Reply:Originally Posted by makoman1860Pulser,  With all do respect, you dont know what your talking about with OF welding.!
Reply:Pulser, No problem. Yes there are actually. You dont see it in structures, as there really arent many structural weldments in aluminum except resistance. Furnace brazed parts you see though. In airlines you see it a lot in duct work , resivoirs , that kind of thing. In smaller general aviation aircraft its mainly seen in fuel tanks, as thats about all thats welded. You also see it a LOT in the repair of aluminum oil coolers where the baked in oil redidue makes Tig about impossible, or un-reliable. Tig became very popular in the 1970's for fuel tanks as it eliminated the need for cleaning the tank after welding with the torch. However chronic leaks, poor fatique properties and such have lead to a strong resurgance of OF welding for those parts. The big bonus, and biggest pain of gas welding is the flux. It de-gasses the molten pool and actually creates a more dense weld bead than tig (better fatigue life, no leaks ). Section up some welds, check them under a scope and youll see what I mean. It also automaticly creates a bead on BOTH side of the sheet ( no tig 'butt crack" on the backside), no inclusions, no holes, just a seamless weld on both sides. But....you have to remove the flux when finished, and its corrosive. So its technical merrits are balanced by economic, for large production. I use both OF and Tig, and have found most professional aluminum shops do as well. i have taught a half dozen people that repair pontoons for boats how to weld with the torch, and they love it for its ability to handle the corroded grungy aluminum, its portability to the boat, and the fact wind doesnt affect it. Tig I use mainly on heavier material ( over 1/8 ) and castings, unless they are really dirty and poor, then its back to the torch. Try it, I think you will be pleasantly supprized!
Reply:Your instructor suggested that you weld O/A is to build up your hand eye co-ordination. Agree with Makoman 1860, brings out some very good points, check out the posts below.http://www.weldingweb.com/vbb/showthread...aluminum+o%2Fahttp://weldingweb.com/vbb/showthread.php...uminum+weldingTheir is an O/A welder "henrob" you may be able to find one on ebay cheap, or your LWS, it is easier because of the slower pace, and relatively low startup cost than tig for beginning welders and you can assimilate it into your OA setup..As far as doing aluminum work now as a fabricator, outsource the aluminum welding.
Reply:The problem when you ask a question about a certain technology, is that you get a lot of answers from people that dont use it. Some of it is fifth hand old wives tales or what-not. Honestly a lot of the myths were perpetuated by the welding machine companies. Think about it, there is a lot more profit to be made on an expensive electric machine than on a few bits of machined brass and a pair of regulators. So the stories filter through the years, like the game of telephone, and pretty soon we have no idea why we think things are the way they are, but they are, so it must be right. Just go ask your LWS about atomic hydrogen welding........they wont know what it is, but Mig is better....and BTW they have some nice machines for sale
Reply:Makoman,are you saying that you would choose to us OA over TIG on a motorcycle subframe like pictured in the original posting?  Could the strength and cosmetic appearance of OA in this application equal that of TIG?  Wouldn't the annealed heat affected zone surrounding the OA weld be many times larger that that of a TIG weld?  I get your point that OA of aluminum is a viable process for some applications, but as you said these are not typically structural, and since the original question is about a motorcycle subframe, I'll have to go back to the intent of my original recommendation that this is not good application for OA, but is much better suited to TIG.
Reply:Pulser, No matter what process is used, you will always have an annealed section next to the weld. If its a tubing section, does it matter if a 1/4" or 1/2" length of it is annealed? Nope, still the weakest link with the same strength when it gets to that point. From and engineering standpoint, the strength properties of both OF and Tig are treated as the same, as the base alloys are the same, fillers are the same, and so on. When I was talking about not seeing many welded structural aluminum components in aircraft, I meant with any process ( except laser, ultrsonic, friction stir, resistance etc ), not just OF. And those that are welded and structural, are almost always heat treated after welding, so its a mute point. Would i used OF on a structure as shown, You bet! Would Tig be a liitle easier, you bet! But for me it wouldnt be worth spending thousands for a machine just for a little more ease. Thats just me. Of course if it was mine, in the end i would heat treat the whole works when finished, no matter what process is used.