Thread: Cast aluminium problems...

5356 is generally the filler I use for the cast motorcycle cases and car parts (commodore sumps) I weld up. Never had the cracking issues you are experiencing though only issues with impurities through the casting. Usually these cracks are due to restraint.

I do make sure the whole job is preheated by "sooting" the job with acetylene soot and then heating until soot disapears.

Gidday

There can be so many variables with a fix like this so sometimes it goes well n others its a journey in frustration that can easily lead to a failed repair. Its often worth doing a google n tralling the Net if your patient enough a few common themes start to surface that really give some great pointers. PArticularly from some of the more established welding forums.

Heres some to kick you off:

forum.weldingtipsandtricks.com • View topic - Aluminum hot cracking
Repairing Aluminum Castings
Weld Talk Message Board and Online Forum - Hobart Welders
Welding Aluminum Cylinder Heads

Id also be trying 4047 rods but HAve also heard 4643 filler rod works well on aluminium casting

Hope this helps

Regards Lou

Originally Posted by NewLou

Gidday

There can be so many variables with a fix like this so sometimes it goes well n others its a journey in frustration that can easily lead to a failed repair. Its often worth doing a google n tralling the Net if your patient enough a few common themes start to surface that really give some great pointers. PArticularly from some of the more established welding forums.

Heres some to kick you off:

forum.weldingtipsandtricks.com • View topic - Aluminum hot cracking
Repairing Aluminum Castings
Weld Talk Message Board and Online Forum - Hobart Welders
Welding Aluminum Cylinder Heads

Id also be trying 4047 rods but HAve also heard 4643 filler rod works well on aluminium casting

Hope this helps

Regards Lou

The first of those is one I didn't come across in the 3 hours I spent scouring the web for any clues, but his solution I don't think will work for me - I really have poured the filler in along with lots of heat, and cooling still inevitably leads to a big bang.

The annoying thing about welding is that everyone has a different method of doing things, some say 5356 is the only way to go for castings, and 4043/4047 always cracks for them, others say 5356 never works for them, but 4047 does. I guess it depends on where your castings originate, and their contents...

Going to 'borrow' the oven from 'her indoors' and see what happens with preheating it, and controlling the temp on the cool down, just because I can do it today (public holiday). If that fails, I guess I'm back to the 4047 rods, if I can get them...

Originally Posted by Stringy

I do make sure the whole job is preheated by "sooting" the job with acetylene soot and then heating until soot disapears.

That was my first thought - sounds like the weld itself is too hot, but the job itself is too cold. I'd try preheat but set less amperage on the welder. Never had the pleasure of repairing a casting though, so not speaking from experience. Good luck with it - Mick.

Originally Posted by WelderMick

That was my first thought - sounds like the weld itself is too hot, but the job itself is too cold. I'd try preheat but set less amperage on the welder. Never had the pleasure of repairing a casting though, so not speaking from experience. Good luck with it - Mick.

Well, I'll let you know in a few hours.... My gearbox cake is in the oven as we speak...

Well, the end result seems to be that borrowing the oven from 'her indoors' improved things. Still have some fine cracks in the corners, which may well be a result of my previous botched efforts, or not being properly welded over on this attempt. They're in very awkward spots to get to both from a cleaning and a welding point of view, and didn't exist there when I started. Was also trying to move fairly fast to get it back in the oven before the temperature difference got too great. End of the day, with a bit of jb weld or similar to seal over the few hairline cracks remaining, you could probably use the casing again, how well it would last I don't know....

Originally Posted by Jekyll and Hyde

The annoying thing about welding is that everyone has a different method of doing things, some say 5356 is the only way to go for castings, and 4043/4047 always cracks for them, others say 5356 never works for them, but 4047 does. I guess it depends on where your castings originate, and their contents...
..

Totally agree...................Often Welding is both an Art and science with a number of paths that can be taken that lead to similar results. What im lovin is that your sharing the journey with us so that we all learn from what you find out


Cheers!

Regards Lou