Questions about brazing aluminum?

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1: What kind of strength can you get from brazing aluminum? How comparible is it to welding it? 2: How much easier is it to do than weld it (with OxyAcetylene)? 3: One question that is semi-related:To weld Aluminum with gas, can you use Aluminum flux-coated stick rods? If so, do you still need to brush liquid flux on the joint?What about these products for brazing?http://tinmantech.chainreactionweb.c...e9b57e478cff48Would I need both? Or would just the flux-cored rods work?
Reply:Gas welding aluminum is really hard.Brazing it is even harder.TinMan (Kent White) is one of the three or four best metalworkers on the planet- he can make it look easy.But it aint.I have gas welded aluminum, with flux and solid rod. If you already a good oxy fuel welder, you can pick it up, assuming you have the exact right flux and rod. It helps to have the fancy 100 dollar goggles, too, as the flux makes a very bright flame, hard to see well with regular goggles.But dont expect this to be an easy or cheap alternative to tig welding- tig welding aluminum is much easier, and a lot less frustrating. I have had horrible luck with flux core aluminum rods- I would skip em altogether, and buy the straight gas welding rod and flux from tinmantech.
Reply:Thanks! What type of rods and flux should I use to weld aluminum with gas (or at least try)? So no flux core or flux coated Al rods?
Reply:Buy the stuff from Kent.(TinmanTech)http://tinmantech.chainreactionweb.c..._id=44#agwfluxLike I said, he is the man- if he sells it, it works. The flux is only 12 bucks, the filler rod 10 bucks- but you need to buy the right stuff for your base metal- and you better know exactly what your base metal is- this is no place for junkyard mystery metal- 3003 would be good, its easy to work with.Besides Kent, the other big guru for this is Ron Fournier-He sells a kit for 35 bucks with rod, flux, and a book. http://www.fournierenterprises.com/gasweld.htmlRon also really knows his stuff- these guys are not salesmen, they are the very best sheet metal guys in the world, people who are routinely given million dollar cars to fix.
Reply:Thanks a bunch! I figure Ill give this a go before seriously looking into TIG welders, heh. BTW, I dont see Al rod on the Tinman site? BTW, I would be mostly welding 6061 allow since that seems to be the easiest to find for a good price, and also seems to be easily weldable. What type of rod do I need to use for the 6061?Thanks again!
Reply:Both websites I linked to sell 1100 series filler rod. They both agree its the easiest to use on most aluminum.6061 is cheap and easy to find, but it doesnt weld as nicely as 3003. But go ahead, buy 20 bucks worth of flux and rod, and give it a try. I would start out with something simple, like 1/8" sheet. Gas welding is pretty much only used these days on sheet, and mostly pretty thin sheet at that. Its done because it does not harden the aluminum, and so auto body guys like it because it is easy to hammer the sheet afterwards, with no sign of the weld appearing.It is not going to be a magic, cheapo alternative to tig or mig, for big stuff, or structural shapes- it will drive you nutty trying to gas weld things like solid aluminum 3/4" round to angle aluminum, for instance. Aluminum conducts heat like crazy, meaning you need to preheat thick stuff, and then its so hot you can barely get near it, and when you get the bigger pieces hot enough, the small pieces have mysteriously vanished, leaving only a puddle on the floor.For sheet, yep, it will work. For structural stuff, start saving your bucks for a tig machine.
Reply:I must be crazy but on that tinman site all Im able to find is "wire." Is that what you are talking about? By "wire" I assume a small spool like for MIG welding... but am I thinking of it wrong? Question:I know this is ghetto, but I have an essentially full 1# spool of .035 Al wire for my MIG welder that I bought to test the feed capabilities (the results of said test being what made me go with the O/A). Can I use that is filler? What if I took long pieces, folded them in half, and twisted them with a drill? I figure why not use that spool instead of letting it sit there and go to waste? Or would that not work? Sorry for the newb questions! And thanks for the great replies!
Reply:Originally Posted by JMcDonaldBTW, I would be mostly welding 6061 allow since that seems to be the easiest to find for a good price, and also seems to be easily weldable. What type of rod do I need to use for the 6061?
Reply:Ok, I bought some flux and goggles from FournierEnterprises last night. The MIG wire I have is the 4043 kit, so I suppose that will work. Gonna try it out soon to see if I should invest in a spool gun MIG or a TIG welder instead.
Reply:TIG is fun.  I think you may like it.   Once you do it for even a short while, you feel like you can weld anything.  Give it a try . . .
Reply:Hey JMcDonald,I recognize the name from the MR2OC.  I too wanted to get in to welding Al about a year and a half ago.  I bought the TM Meco torch kit and Al flux.  I have been using 4043 TIG rod for filler for most Al as I typically use 6061 for the base metal.I would say it is very tricky to learn to weld Al with gas, but given enough practice you will be able to learn.  Some tips I could lend:- The TM filter glass works very good- It is ALL about heat control- Use filler nearly the same diameter or smaller than as the base- Clean with SS brush with soap and water before welding- Clean with acetone just prior to application of the torch- Use a carburizing flame- Apply flux to both sides of piece- Preheat larger pieces with torch at a distance to avoid oxide formation- For the best possible results, if you see any gray oxide formation stop, cool the piece, wire brush under water, re-apply flux and start again- Liberal use of flux is not a bad thingEric
Reply:Brazing Al is tough. The brazing material melts very close to the temperature of the Al. I think welding is a better solution in most environments. Brazing may work better in a manufacturing facility.
Reply:Originally Posted by ebakerHey JMcDonald,I recognize the name from the MR2OC.  I too wanted to get in to welding Al about a year and a half ago.  I bought the TM Meco torch kit and Al flux.  I have been using 4043 TIG rod for filler for most Al as I typically use 6061 for the base metal.I would say it is very tricky to learn to weld Al with gas, but given enough practice you will be able to learn.  Some tips I could lend:- The TM filter glass works very good- It is ALL about heat control- Use filler nearly the same diameter or smaller than as the base- Clean with SS brush with soap and water before welding- Clean with acetone just prior to application of the torch- Use a carburizing flame- Apply flux to both sides of piece- Preheat larger pieces with torch at a distance to avoid oxide formation- For the best possible results, if you see any gray oxide formation stop, cool the piece, wire brush under water, re-apply flux and start again- Liberal use of flux is not a bad thingEric
Reply:Yes, what I mean by carburizing is rich.  Not just off neutral, but a nice size second cone in order to minimize oxide formation in the weld.Preheat is not something I have measured as far as temperature.  You should get the piece hot enough such that fusion can occur fairly rapidly in the weld area.  You can cause the base material to melt quickly with a very aggressive flame, but you don't have a lot of control (easy to blow through).  It is better in my limited experience to preheat the base before attempting to weld thereby allowing a smaller less aggressive flame.The preheat area will depend on the material thickness and overall size of the piece.  If small and thin, a quick preheat within a window of 2-in of the weld zone will probably be sufficient.  Make sure to have flux on the actual weld zone before or just after you begin the preheat.  You can also turn the torch up for a quick preheat then back down just before welding.Another quick tip:  Pull the torch away gradually from the weld in order to help with minimizing cracking.  If the weld does crack, wire brush it, re-flux it, and make another pass.I know this is said often, but the more you practice, the better off you will be before welding anything of meaning.Eric