o/a welding question...

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ive been trying to get myself a TIG machine, but cash flow comes hard these days. but i already have a oxy/acet. torch set a friend gave me for free. he used it for brazing when he did AC and refrigerator repair. i want to use it to weld aluminum. nothing thicker than .50 inch and most likely nothing smaller than .125 inch. primarily for making intake manifolds and piping for performance cars.few questions: i have some AluminRod i got from Harbor Freight. im guessing this stuff is junk. but maybe im wrong. where would i get the rod that would come out cleaner weld?say if i was welding a .125in wall thickness pipe to a .50in plate, would i pre-heat the plate first? best way to do this would be my oven? (i do this at home)any tips would be great, thanks ahead of time...Lincoln Square Wave 175 TIGLincoln 110v flux core welder (my 1st)Clarke 180EN MIG
Reply:Ok can you make it any more difficult? Perhaps you can try and learn while standing on your head and reciting Shakespeare? Just kidding!Learning to weld alum with the gas torch will be a tough challenge, especially if you don't already know how to weld with gas. The 1/8" to 1/2" difference in material thicknesses will also up the difficulty significantly.I'm learning to tig alum. On 1/4" T joints, my syncrowave 200 takes quite a bit of time to heat the material to get it hot enough to start the weld. It sort of has to be preheated. That 1/2" material will suck up heat fast. I'll almost guarantee that it will need to be preheated in some way. The 1/8" will melt long before the 1/2" gets up to temp.What you need to use to preheat the 1/2" will depend on how big the piece is. An oven would work well for a larger piece, so would your torch if the piece is smaller. A big heat gun was suggested for my stuff. The basic idea is to get the pieces hot, so that they will melt at the same time as oppsed to the small piece melting while the large piece just sucks up the heat getting warm.Good luck and keep us posted.
Reply:http://www.tinmantech.com/
Reply:As DSW asked, can you make it any more difficult? LOL. I have two tips and the rest is up to you. Allstate Silcore rod is the easiest I ever used, get it at your LWS. The flux is inside like flux core wire. Get a lens that absorbs the orange flare from the flux, you can't see what you are doing without it and you really need to see well with aluminum. Let us know how it works out.
Reply:thanks for the tips...and i know, it will be hard. but thats not saying it cant be learned. and if i'll be saving *$1500 (the price of the AC/DC tigs i been looking at) for the time being by learning this skill. its well worth it.Lincoln Square Wave 175 TIGLincoln 110v flux core welder (my 1st)Clarke 180EN MIG
Reply:Originally Posted by sen2twothanks for the tips...and i know, it will be hard. but thats not saying it cant be learned. and if i'll be saving *$1500 (the price of the AC/DC tigs i been looking at) for the time being by learning this skill. its well worth it.
Reply:sen2two, do yourself a favor and take your money and sign up for a good night school welding class at your local votec. You will waste a lot more money trying to teach yourself. First you will need to learn to weld steel where you can see what is happening. That way you can learn to manipulate the heat and the rod to get what you want. Then you can move on to alum of similar size and then different sizes.As said, $1500 for an AC/DC tig is cheap and I'll almost guarantee that it will not do 1/2" alum. There's no "cheap" way to do alum.
Reply:What about stick welding?  ...1/2" is thick, still.  With o/a you won't have trouble doing 1/8 to 1/8".   I can't imagine what it would take to do 1/2".    You'll benefit from larger tanks.If you have no tig or o/a experience, then you might pick up o/a aluminum weld easily.  I think expectation of a flowing puddle confuses and frustrates some.Once you figure out what you are doing you will be amazed at how easy it is to make a solid, leak free weld.  Heat and distortion management are another issue. Let us know how it works out.Oh yeah,That Alumiweld stuff works.  It take a lot of heat, still.  A lot of heat.  A lot of heat.  A turbo torch at minimum for 1/8".  I don't know about the HF stuff.A course would be worth taking or purchasing.  Also, matching Al Alloys and tensile strength and melting temperatures, might determine that brazing might be better than welding.
Reply:Have you looked in Craigs List or the Equipment Trader for a used tig?MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:One of your biggest problems is going to be seeing when the aluminum is melted.
Reply:i have searched my local listings and craigslist. for a minute i thought a TIG was made of gold...i'll most likely get one in the future. but it dosnt hurt to be well rounded in skills.i will be taking a welding class, an opening dosnt clear up for about 3 months. so im waiting until then. but i do like learning o my own. i taught myself to stick, flux (no gas) steel, MIG steel and aluminum (getting better still on the aluminum) on my own. just playing around with it until it looks right. and go from there...where can i get those blue glasses that let you see better when o/a welding?Lincoln Square Wave 175 TIGLincoln 110v flux core welder (my 1st)Clarke 180EN MIG
Reply:I started a thread on Al stick weld beads.  Search my threads dated, 10/20/07 and 10/18/07.  I would post the link but last time I did one did not work.
Reply:Originally Posted by sen2twoi have searched my local listings and craigslist. for a minute i thought a TIG was made of gold...
Reply:You might have to look for an older, basic ac/dc tig/stick machine, like a Dialarc HF or Idealarc, if you have the juice available to run one of those monsters.  They are usually not too much money if you find someone selling one.  The Syncrowaves go for alot more, so do the inverters.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:The old cobalt blue glasses are a thing of the past. Check with your LWS, I believe there is a lens made now that does the same thing.
Reply:If you want to do some learning with O/A, then go fot it, bit if you are planning on building intake manifolds for performance cars as you say, O/A is not going to cut it. Welding up a set of 0.065" aluminum intercooler pipes with a standard O/A torch would drive me somewhere close to suicidal. Some of the fancy little torches seem to do a good job if you get everything just right, but at the end of the day it isn't the right tool for the job. And you can find an AC/DC TIG for much cheaper than $1500 is you know what to look for and can install a 60A or greater 220V in your workspace. An old DialArc HF, Hobart CyberTig, or Lincoln of similar vintage will work fine.Yeah square wave and adjustable wave balance are nice features, but an old sine wave machine with high frequency will still be lightyears ahead of an O/A setup.
Reply:A GTAW Machine would give you more precise control of the puddle and a much smaller HAZ.However, OxyFuel welding of Aluminum works well, with good penetration and speed. If you are careful you will even be able to make some pretty beads. OxyFuel welding of aluminum would also be fortuitous when you need to weld in a remote location with no power and don't want to lug a bunch of equipment in.Aluminum from 1/32 to 1 in. (0.8 to 25.4 mm) thick may be gas welded. Heavier material is seldom gas welded, as heat dissipation is so rapid that it is difficult to apply sufficient heat with a torch. When compared with arc welding, the weld metal freezing rate of gas welding is very slow. The heat input in gas welding is not as concentrated as in other welding processes and unless precautions are taken greater distortion may result. Minimum distortion is obtained with edge or corner welds.In gas welding thickness over 3/16 in. (4.8 mm), the edges should be beveled to secure complete penetration. The included angle of bevel may be 60 to 120 degrees. Preheating of the parts is recommended for all castings and plate 1/4 in. (6.4 mm) thick or over. This will avoid severe thermal stresses and insure good penetration and satisfactory welding speeds. Common practice is to preheat to a temperature of 700°F (371°C). Thin material should be warmed with the welding torch prior to welding. Even this slight preheat helps to prevent cracks. Heat treated alloys should not be preheated above 800°F (427°C), unless they are to be postweld heat treated. Preheating above 800°F (427°C) will cause a “hot-short” and the metal strength will deteriorate rapidly.After the material to be welded has been properly prepared, fluxed, and preheated, the flame is passed in small circles over the starting point until the flux melts. The filler rod should be scraped over the surface at three or four second intervals, permitting the filler rod to come clear of the flame each time. The scraping action will reveal when welding can be started without overheating the aluminum. The base metal must be melted before the filler rod is applied. Forehand welding is generally considered best for welding on aluminum, since the flame will preheat the area to be welded. In welding thin aluminum, there is little need for torch movement other than progressing forward. On material 3/16 in. (4.8 mm) thick and over, the torch should be given a uniform lateral motion. This will distribute the weld metal over the entire width of the weld. A slight back and forth motion will assist the flux in the removal of oxide. The filler rod should be dipped into the weld puddle periodically, and withdrawn from the puddle with a forward motion. This method of withdrawal closes the puddle, prevents porosity, and assists the flux in removing the oxide film.Last edited by MEWelding.com; 05-01-2008 at 07:24 AM. Maine Welding Company & Wrought Iron Powered by Custom Web Development