Welding cast aluminum

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Guys, I've got some cast aluminum that needs welding.  Not sure which filler rod to use.  I don't know the aluminum type either, but it is off an old Emglo compressor, and is a threaded fitting for an air gauge.  Thanks, Nick.
Reply:I just finished welding a casting and used 4043, but then again, that's all I had available, so i don't know if this is the right rod to use.  Actually, I just opened up my Tig Welding Handbook and 4043 seems to be used for most aluminum types, at least as an alternate filler. Remember to keep the area as clean as possible, then clean again after welding or stoping and before continuing.
Reply:Well, I had a lot more luck with the 5356 rod than the 4043.  Just welded on a huge lump of the stuff, and drilled and tapped it.  Seems to work.  Definitely not going to win any good looks contest, but it works.  The cast was quite dirty, and since I had trouble cleaning it, the first round of beads was tough.
Reply:Snap any pics?
Reply:No no no.  Very nasty looking.  One of those, "well, that will work, but it looks like crap.
Reply:Chicken.    Post pics anyways, we can use them as a "how not" example.
Reply:I have got to get some pictures of my stuff up.  I have lots of "how NOT to's" that might make for some good laughs.  We should start a new thread called "welds gone wild", welds that appear to have been made by a drunken spring breaker.After I screw something up, it usually ends up in a pile of scrap that I always have inteded to re-use.  The pile is growing.  Nick, if your weld works, it's better than every one of the welds in my pile........that didn't.Smithboy...if it ain't broke, you ain't tryin'.
Reply:5356 should be used for all aluminum castings...and anything thats going to be sent out for anodizing...the anodize will not stick to 4043....i've fixed many many destroyed alumimum cylinder heads for race cars5356 all the waysome castings must be pre heated with a torch before welding or cracks will result...using straight acceteline "blacken" the part and then heat 'till the black soot dissappears..and start welding!(when i fix heads i usually place the head in a BIG box of vermiculite and let it cool s..l..o..w..l..e..y...keeps the cracking down ...zap!
Reply:My book says for low alloy aluminums, such as cast aluminum, use 1100 for maximum strength and EC, or 1260 for maximum ductility.
Reply:I use A356 TIG rod when I weld cast aluminum, I clean the part best I can , give it some pre heat with the oxy/ace and weld it up, if it dont look good I grind it off and repaet the processhere is a link to the rodhttp://www.airgas.com/browse/product...&WT.svl=100134
Reply:Interesting thread.  What are the most common casting materials in automotive use?  What advantage do you see when using the 5356 over the 4043 and likewise A356 versus the others?  Less tendancy to crack?Eric
Reply:All castings are of very low alloy content, almost pure aluminum.
Reply:4043 has too much silicone in itgreat for billetnot for castings...zap!
Reply:What if you are welding sheet (3003 or 6061) to a cast (unknown alloy) automotive intake manifold?  Would 5356 be the filler of choice?
Reply:i built a 2X4V intake for a 427 fordbut we started with all billet mat..6061T-651i used 4043 exclusivallyi'll scan the pics and post soon!...zap!
Reply:but i have done as you are suggesting..welding cast to billet and 4043 is a good choice...zap!
Reply:I almost always use 4043 for welding aluminum. As a matter of fact, I just got some carts I need to repair and I'm gonna use 4043. I fixed a leak on a GM intae manifold with 4043, also a high dollar cast valve cover for a 302 ford with the same 4043.
Reply:Originally Posted by orphan68I almost always use 4043 for welding aluminum. As a matter of fact, I just got some carts I need to repair and I'm gonna use 4043. I fixed a leak on a GM intae manifold with 4043, also a high dollar cast valve cover for a 302 ford with the same 4043.
Reply:Zapster,Thanks for the advice, I'll give the 4043 a shot on a the piece of material that I will be cutting away before I weld on the final piece.Eric
Reply:Originally Posted by zapster5356 should be used for all aluminum castings...and anything thats going to be sent out for anodizing...the anodize will not stick to 4043....i've fixed many many destroyed alumimum cylinder heads for race cars5356 all the waysome castings must be pre heated with a torch before welding or cracks will result...using straight acceteline "blacken" the part and then heat 'till the black soot dissappears..and start welding!(when i fix heads i usually place the head in a BIG box of vermiculite and let it cool s..l..o..w..l..e..y...keeps the cracking down ...zap!
Reply:Originally Posted by OscarZap,should 5356 be used even for the combustion chamber that will see elevated temperatures?  Cyl head is a casting, not billet.
Reply:Originally Posted by zapsterWorks on pistons too.Done it many times and things are still alive..Some disagree but that's OK.I go with what works.Just like this 6 year old thread......zap!
Reply:i use 4043 for everything, cast, 6061, 5053, never had any issues. ive welded in combo chambers before too and no issues.mike
Reply:Originally Posted by killingmachinei use 4043 for everything, cast, 6061, 5053, never had any issues. ive welded in combo chambers before too and no issues.mike
Reply:Originally Posted by shovelonI agree with Zap. 5356 is a better choice in some cases hands down. Like stripped threads and worn valve seat lands.Originally Posted by OscarWhy is that?
Reply:yeah ive just welded indention's in the chambers, ive never had to weld a seat recess before. but if i do thats good info to know, thanks shovelon.mike
Reply:Originally Posted by shovelonBecause 4043 is too soft for threads, and also will not take a press fit valve seat well. 5356 is not only stronger but more ductile.