Brazing question

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I picked up some Hobart Alum. brazing rod today. It says no flux needed on the tube. I cant make it work. I cleaned with sandpaper and acetone and tried to braze a lap joint - no joy!Can someone tell me if this stuff is really brazing rod or is it really just strips of alum.?  Is there such a thing as brazing alum.? How do I do it?I have flux for brazing steel - should I use that? I have no probs brazing steel btw.Happy new year.Lincoln PowerMig 180cVictor O/ABandaids and aspirinI don't know what I don't know!?
Reply:i dont think you can braze aluminum ...i may be wrong though . good luck though
Reply:Ok. I'll try it as a filler material next.Lincoln PowerMig 180cVictor O/ABandaids and aspirinI don't know what I don't know!?
Reply:ok i went and looked online i guess you can braze it..and here all these years ive been welding it...lol . if i were you id call the local weld shop and ask them we all know you will get a million dif ways to go about it here what are you using for a flame ?
Reply:what are you trying to braze?
Reply:I'm trying to use 3/4" angle to make a frame for some alum. diamond plate. Basically its a box like briefcase. I'm using oxy/acetalene.Lincoln PowerMig 180cVictor O/ABandaids and aspirinI don't know what I don't know!?
Reply:search this site I have seen some post about brazing alum ..  I have tried it before with no luck hard to get the heat i found
Reply:Yah I searched. I get the feeling it may be time for a spool gunLincoln PowerMig 180cVictor O/ABandaids and aspirinI don't know what I don't know!?
Reply:It is a brazing alloy if it melts much below the melting point of the base metal (and above a certain temperature so as to not be 'soldering'). After cleaning both the base metal and possibly the filler, you need to manipulate the flame carefully so that no oxides can reform before you ad the filler. What filler are you using? That will determine what type of flux can be used with the rod. Some fluxes might work with aluminum by forming a shield to keep the O2 away rather than dissolving already-formed oxides; I don't know how well borates do this, or if they might interfere more than help. Most of the steel brazing fluxes use at least some borates in them.
Reply:Originally Posted by skywestI'm trying to use 3/4" angle to make a frame for some alum. diamond plate. Basically its a box like briefcase. I'm using oxy/acetalene.
Reply:Cronatron Welding Systems sells a product called Low Temp Aluminum Brazing Alloy F-53, needs a flux with it.  Flux is a thick brown syrupy stuff and acts as a temp indicator.  Clean what you're brazing, apply flux, heat with slightly carburizing flame, flux will dry, turn white, then back to a liquid again, temp right to apply brazing rod then.  Can be used on aluminum, or aluminum to copper/brass.  Works great.You can also buy aluminum solder in hardware stores for use with propane torches.
Reply:Ack throw that garbage away. Its a zinc based pot-metal type rod. Actual brazing uses a high silicon content aluminum based filler and an aluminum brazing flux. Its not the same as other fluxes so dont even bother trying them. Go to www.tinmantech.com for an easy source for the brazing alloy and flux. 4047 is a popular brazing alloy, as is 4043, most of the trade name brazing fillers are just this alloy. But why braze it when you can weld it?? Same torch, just the same filler as Tig welding and an aluminum welding flux.-Aaron
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Reply:We braze aluminum aircraft parts every day at our plant in Rockford, IL.The process is a dip braze which uses a bath of molten salts for flux I believe.  The braze paste is an aluminum alloy that melts below the parent material.This would not work for your application though -sorry.  Just wanted to add to those that said it can be done.  We have very good results.
Reply:Originally Posted by obewanWe braze aluminum aircraft parts every day at our plant in Rockford, IL.The process is a dip braze which uses a bath of molten salts for flux I believe.  The braze paste is an aluminum alloy that melts below the parent material.This would not work for your application though -sorry.  Just wanted to add to those that said it can be done.  We have very good results.
Reply:We only use paste on our aluminum brazes.  I have never seen the operation done since I am in Jacksonville, FL, and the work comes from Rockford, IL.  I have seen the parts and qualified their process though.
Reply:i have used quite abit of that hts2000, durafix, alumaloy, fluxless style rod over the years.  it works very well.  i find it is all just about the same, there may be some differences, but the application methods are the same.  there may be difference in the quality, chem composition, etc., but i don't know all the specifics.  i have used it for pot metal, brass, aluminum on a variety of projects.  it is expensiveLast edited by Scott Young; 01-05-2009 at 09:22 AM.
Reply:Originally Posted by Scott Youngi have used quite abit of that hts2000, durafix, alumaloy, fluxless style rod over the years.  it works very well.  i find it is all just about the same, there may be some differences, but the application methods are the same.  there may be difference in the quality, chem composition, etc., but i don't know all the specifics.  i have used it for pot metal, brass, aluminum on a variety of projects.  it is expensive
Reply:All-State also has one of those (Zinc and Cadmium) rods, plus a number of 'real' Aluminum solders and fluxes. It also has a rod with the flux inside the rod. I forget if it's for welding or brazing and can't check right now.
Reply:Originally Posted by Oldiron2All-State also has one of those (Zinc and Cadmium) rods, plus a number of 'real' Aluminum solders and fluxes. It also has a rod with the flux inside the rod. I forget if it's for welding or brazing and can't check right now.