Ive got a some aluminum castings that need repair (raw unmachined SP stromberg tops) and figured since i dont have the equipment or skill to weld aluminum any other way i'd dive in and OA them. Im pretty good a welding sheet steel with a torch, but i'd assume that this is a bit of a new world. Any advise?
Preheat the parts up to 200 degrees or so and same after you weld them let it cool down slowly. It has been a while since i have been around a set of Stromberg's but take a good look at what they are made of some of the carbs are made out of pot metal and that is a whole different ball game when it comes to welding. Just my two cents.
A set of SP tops are NOT what I would be learning how to weld aluminium!! I would get someone that does it for a living rather than risk screwing up on them. Doc.
Exactly. At the very least get some junk tops and practice on them. If it were cast aluminum for sure and not pot metal I would suggest that TIG welding is your best bet, preheat to 400 and then begin welding. The aluminum will flow in like butter that way.
Dont get me wrong i'm gunna practice, and i'd rather not pay anyone else to do something i am totally capable of doing myself. I figure this is a good skill to learn too, if i can O/A aluminum it means i dont need to buy a tig, infact other than frame work i wont be doing any electric welding. As for learing the skill, it took me a few days to get hammer welding to the point where i dont need filler, and stainless with a touch seems easy, so i doubt it'll be that hard to learn especially when all i need to do is goober a little more meat around the edges What size and type of rod should i look for?
Gas welding alum. sheet is one thing small castings is something else. You are about to make a couple of aluminum lumps that you may be able to use for ash trays. I would find some one with a TIG and pay him to do the welding. Rex
Don't let your ego get in the way of having it welded by a professional. It may be pot metal, not aluminum.
I got some of that "aluminum brazing rod" stuff that they sell at swap meets yesterday, they had it at the welding store, it's called "3 in 1" aluminum welding rod or something. You can also get it from several vendors on ebay. It is an interesting alloy that melts at a much lower temp than aluminum melts at. It is mainly used for repairing castings, and if the carb top is indeed cast aluminum it should work for what you need. You'd want to practice on something else first to get the hang of it, but it's not very difficult. And you can use a MAPP gas bottle in a cheap handheld propane torch, it's easier to control the heat this way vs an OA torch. No flux is used with it, just rub the rod on the base metal as you heat the part, and when the rod melts, you add rod until it's built up all the way. Of course you need to clean the part well, preferably with a stainless wire brush, first. I've only welded one thing with it, but it worked like the instructions say, and like the guy at the swap meet showed. I do have some experience welding, brazing, and soldering with a torch, but I'm by no means a great welder.
Thanks squirrel, but im kinda hesitant to use stuff like that because I'm gunna be chromeing them too, Anyway I have a chev intake i'm gunna attack first but these were crude knockoff $25 a pop raw castings that come up short in a couple spots, i'd prefer to gamble on doing the fix myself, if i turn them into a pile of goo i can always add more aluminum and fix the from there after all. So do i flux it? What kind of tip? Rod?
I have used the rod squirrel talked about. I have welded the hinges back on my charcoal grill lid with it. The gas pedal pivot on a F250 . Worked great .It acts like solder . Tried to weld two halves of a a/c dryer together to make a small gas tank and failed . It wouldnt mix into the metal just stuck on the surface . It would pop apart when hit. You have been advised proceed at your own risk.
Well i gave it a shot on an old chevy starter nose, piece of cake, it was pretty porious afterward, but i didnt have any flux and burned it a little, i'm gunna get some flux and rod and practice up a little more, but i dont know what you guys are so scared of!!!!
i think they are scared of making it worse than it was to start. i am wanting to be able to gas weld alum too. but i picked up a miller tig with high frec over the weekend so i will practice with that first. when i have tried in the past to gas weld alum i had mixed results, but it may have not been clean enough. sounds like you are off to a good start though! good luck.
First , you need the right glasses for o/a welding aluminium, i got mine from the henrob guy. They say welding with normal welding goggles is real bad on the eyes. Second, flux makes a huge difference. I`ve only welded .063 3003 with the henrob, haven`t done a casting yet, but would think Rex has it right about preheating. Gary
Ok, I'm going to mention something that may show my own stupidity. Aren't you supposed to weld aluminum with hydrogen and not acetylene? From what I remember, OA is too hot to maintain control unless you are REALLY good at it to begin with. Hydrogen burns at a lower temp and keeps you from making an ashtray. With aluminum melting at ~1200F (660C) and it's really high heat transfer characteristics, I've heard (don't know from experience) that hydrogen is the best for it. Also, flux and the correct goggles because the glare can't be cut with regular goggles. I've used the 3-1 rods, they work good and flow well. From wikipedia... Hydrogen Hydrogen has a clean flame and is good for use on aluminium. It can be used at a higher pressure than acetylene and is therefore useful for underwater welding and cutting. It is a good type of flame to use when heating large amounts of material. The flame temperature is high, about 2,000 °C for hydrogen gas in air at atmospheric pressure,<SUP id=cite_ref-WT_5-0 class=reference>[6]</SUP> and up to 2800 °C when pre-mixed in a 2:1 ratio with pure oxygen (oxyhydrogen). Acetylene Acetylene is the primary fuel for oxy-fuel welding and is the fuel of choice for repair work and general cutting and welding. Acetylene gas is shipped in special cylinders designed to keep the gas dissolved. The cylinders are packed with porous materials (e.g. kapok fibre, diatomaceous earth, or (formerly) asbestos), then filled to around 50% capacity with acetone, as acetylene is acetone soluble. This method is necessary because above 207 kPa (30 lbf/in²) (absolute pressure) acetylene is unstable and may explode. There is about 1700 kPa (250 psi) pressure in the tank when full. Acetylene when combined with oxygen burns at a temperature of 3200 °C to 3500 °C (5800 °F to 6300 °F), highest among commonly used gaseous fuels. As a fuel acetylene's primary disadvantage, in comparison to other fuels, is high cost. As acetylene is unstable at a pressure roughly equivalent to 33 feet/10 meters underwater, water submerged cutting and welding is reserved for hydrogen rather than acetylene.
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