cast alum repair....

Rick_H · Thu Oct 16, 2014 9:09 pm

Well we sent a motor out for rebuild and the cast alum drive housing that was attached got cracked. The vendor welded the crack but it has some porosity and leaks gear oil. As a temporary repair a guy smeared some silicone caulk over it and it surprisingly works.

Now here is where I come in.... Since I am the most competent welder they want me to weld it up this weekend since the new housing in over a month out. I really won't have the time to remove it, clean it and tig it like of prefer. I've only got about 4 hrs or time in between runs and that includes some fire watch time. So I'm thinking drain the oil, wire brush the silicone off, grind there crappy weld job, wipe with acetone, preheat with a torch and hit it with some beads from the spool gun on my Miller 252, 4043 wire. I know I'm going to have some oil trying to pull up but I think this is my only option unless I put epoxy over it.... Kills me to use that instead of repairing properly.

Just wanted some opinions from my welding brothers.

dirtmidget33 · Thu Oct 16, 2014 10:34 pm

If new housing is coming in a month just keep it going until then drain oil clean off silicon wipe down and JB weld it

I hate the stuff but if it only needs to be temporary and they won't let you TIG it right. Then they deserve second rate repairs

Of course 4hrs won't give the stuff time to cure need 24hrs

TamJeff · Fri Oct 17, 2014 12:31 am

Patch 'over' the crack with an external patch of some 11 gauge scrap. If you can anneal the 11 gauge, you can patch irregular shapes by first strategically tacking the annealed piece, and it and hammering it to fit as you go. This will allow you to make a neat and continuous weld on the surface of some cleaner metal. Radius any corners to make it neater yet. It will almost look like it is supposed to be there like a factory repair.

I anneal and puzzle cut my patches to fit into some pretty intricate shapes.

motox · Fri Oct 17, 2014 5:43 am

tamjeff you had mentioned this process in an earlier post.
i have used it several times since. works great..

Rick_H · Fri Oct 17, 2014 8:47 am

Good idea Jeff I had not considered that....I may have enough room to pull that off its in a bit of an awkward area. Do you use the carbon burn off trick to know the right temp? Its something I've read about and have always wanted to try but have never done.

TamJeff · Fri Oct 17, 2014 1:02 pm

Rick_H wrote:Good idea Jeff I had not considered that....I may have enough room to pull that off its in a bit of an awkward area. Do you use the carbon burn off trick to know the right temp? Its something I've read about and have always wanted to try but have never done.

I don't use the carbon trick but I have before. Instead, for these smaller pieces, I use a mapp torch. I watch the surfaceof the aluminum where the flame 'washes' it. Once the flame starts to pick up an orange tint in that zone, it is ready and I quench it suddenly. Most of the 11 gauge I have is 5052.

Even if you have to put the patches in pieces, it's still way more effective in stopping leaks on cast, or any other contaminated metal for that matter.

TRACKRANGER · Fri Oct 17, 2014 8:41 pm

Rick, were you referring to the carbon trick for preheating the cast, or for annealing the patch? I suspected it was for pre-heat.

Trev

TamJeff · Sat Oct 18, 2014 6:22 pm

If there is any confusion on my post, I anneal the patch material so it will conform to the irregular casting. Also, patching almost mitigates the need for preheat because it is much less likely to crack, provided the machine is capable enough.

Rick_H · Sun Oct 19, 2014 12:21 pm

TamJeff wrote:If there is any confusion on my post, I anneal the patch material so it will conform to the irregular casting. Also, patching almost mitigates the need for preheat because it is much less likely to crack, provided the machine is capable enough.

No confusion on my end, I was also talking about the patch. After getting it apart and seeing what I was dealing with I found 2 small pin holes that were barely seeping and a crack/chip and the main center seal, leaking like a sieve. So I filled the pin holes and epoxied the seal housing crack since I couldn't weld it as it was right against the seal. The new one is on the way....

xwrench · Sun Oct 19, 2014 12:37 pm

Nice looking job. Especially considering the suboptimal conditions you had to deal with.
Cheers.
-Eldon

TRACKRANGER · Sun Oct 19, 2014 7:29 pm

Thanks Rick for the clarification on the heat use. I wasn't sure.

Nice repair. Looks like you used the sandblaster to give yourself a fighting chance?

Trev