Alum pot metal rod and a torch

[aametalmaster]

I got some Crown Royal Kirkrod a few years back just to try it out. But i haven't found anything i couldn't weld with my spoolgun so i never used it, until today. I took some 1 1/2" OD alum pipe cut lengthwise and vise gripped it back together with a small gap prob equal to the sawblade. Then i torch welded it with the RK rod and it welded great. I couldn't hand break the parts when i was done...Bob

[Aerometalworker]

Be careful using that zinc filler. And also be careful calling it welding, as its not even close. The base metal tends to absorb some of the zinc at temperature and depending on the alloy, makes the base metal brittle. Its an OK emergency BRAZING rod or on pot metal castings, but I wouldnt rely on it for anything. I see a lot of aluminum car bodies with that garbage on them, and I end up cutting out the entire area to be able to gas weld it back up again. I think its mostly sold at flea markets by the equivelant of modern day gypsys, unfortunately a lot of people believe them.

-Aaron

[fun4now]

there is a site that sells several diferent kinds of rods for aluminum joining but its realy much more like brazing than actualy welding. torch or TIG would be the best long term structural option but soem things it would be ok for a non strees repair or as a temperary fix knowing the temp. fix could end upo making the fix much more complicateed.
i'll see if i can find the link to the site , they can send you out some good info on it.
HF also sells a similer aluminum brazing rod, again not welding just brazing.

[aametalmaster]

Thanks guys, i wouldn't trade my spoolgun in for it, but i have seen some parts fixed with it that looked good. Nothing structrual just junk castings...Bob

[fun4now]

yep , thats about where its best suited i would think. they do make some prity impressive claims but i think i would only use it like ya said quick nonstructural fixes.

[Little]

I got some HTS2000 alum brazing rod. I built up some corrosion on a water pump outlet and it seemed to me to hold well. i tried it on some 18ga 3003 al and had a little less luck, but I think it'll work for small stuff. Now, the trouble is I have an Allard nose cowl with some stress cracks that a guy wants me to try to fix. I don't know what alloy it is. but its been bondoed and sanded to paper thin thickness. I don't think I'd do too well with the tig because its so dirty and thin. Don't want to have to replace the whole piece on the car.
makoman1860, suggestions? You don't like the brazing for small (less than 1") cracks?

[Aerometalworker]

I got some HTS2000 alum brazing rod. I built up some corrosion on a water pump outlet and it seemed to me to hold well. i tried it on some 18ga 3003 al and had a little less luck, but I think it'll work for small stuff. Now, the trouble is I have an Allard nose cowl with some stress cracks that a guy wants me to try to fix. I don't know what alloy it is. but its been bondoed and sanded to paper thin thickness. I don't think I'd do too well with the tig because its so dirty and thin. Don't want to have to replace the whole piece on the car.
makoman1860, suggestions? You don't like the brazing for small (less than 1") cracks?

I would stay away from that flea market rod especially for stress cracks in sheet. thats exactly the thing I end up re-doing due to the base metal getting brittle and cracking even further. The torch works perfectly for this kind of work with just the right flux, your normal tig rod, and some practice. Check out Kents site at www.tinmantech.com for details and pictures. If you try to tig it either backpurge or use a backing flux, otherwise youve lost some of your metal thickness to oxidation. Have fun!!
-Aaron

[Anti-GMAW]

Being the metals so dirty I'd suggest somthing with flux. Flux forming proccesses are generaly better at scavenging garbage out of the weld pool then gas sheilded proccesses. I'd go with makoman1860's suggestion about backing the weld with a flux.

[Aerometalworker]

I forgot to add this comment about fluxes.

Be sure to use a WELDING flux, there are many BRAZING fluxes out there for aluminum, and most welding shops dont know there is a difference. Brazing fluxes have either Zinc Chloride or Zinc Flouride in them, these are not good as they alloy with the molten aluminum. Use either Aladdin aluminum WELDING flux, or Kents as posted above. Mix with spring water to a paste, paint the backside of the part (after well cleaned with alcohol) and Tig away, makes a beautiful bead on the back side, also great for tanks. Good Luck!
-Aaron

[Little]

Thanks, guys. Great tips. I'm going to find some al flux. Do you guys suggest using 1100 rod? Or is 4043 good for this old 1948 car?
Thanks again
Little