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How to repair cast aluminum transmission case

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Thanks once more for all of the suggestions.

I agree with everyone that the location makes the strength less important, but my wife disagrees.

I called the people that make Metalset A-4 adhesive this morning and a tech guy said to get it welded.

I then proceeded to scare the heck out of myself researching the difficulties of welding of cast aluminum that has probably been contaminated throughout with grease and oil. The most interesting thing I found was Techno-weld rods, but I doubted my ability to get the housing up to 750 degrees with my handheld propane soldering torch.

I dropped off the tranny today with Bubba (that's his name) at a local marine fabrication shop. He looks like one of the ZZ Top guys and he had an Austin taxi converted for drag racing in his shop, so I figured for $75 how bad could it turn out?

I'll report back on the results tomorrow.

Michael
 
Yesterday, PC mentioned on page 1 of this thread that you can also solder aluminum. I had totally forgotten about that.

I have used a product referred to generally as "rub-on" solder. It is specifically made for aluminum. You clean and prep the area just like you were going to weld it (complete with bevels and such). You heat the area to be soldered and as the heat builds you remove the flame and strike the surface of the aluminum with the solder rod like you were striking a match. When the base metal is hot enough the rub-on solder melts and wets the surface. You keep doing that until the solder fills the bevel. There is something in rub-on solder that cuts through the aluminum oxide on the surface and which makes it possible to wet the metal. The rub-on solder also has a lower melting point than aluminum itself so there is less risk of melting holes through the part.

However, I have only used the product on small parts. It would take a lot of heat to solder the broken bolt eyelet back on a gearbox. While I have used MAPP gas for large repairs, I suspect a transmission would require an oxy-acetylene torch.
 
Doug-

The solder is the Techno-weld rods. I watched a video of the technique and it looked really convincing. Works at around 750 degrees.

The welding on my unit is done, was cheap, and looks good. His solution was to build up the weld in the area under the flange where it will be hidden by the mounting on the engine. You can barely tell that it was repaired.

I didn't ask to many questions about the technique.

Michael
 
Michael,

Glad that worked out.
 
Great! I believe you may find this Bubba fellow a handy guy to know. Good for the both of you. :cheers: Bet you feel better now that it's been welded. It never hurts to know a fabricator. The best ones I know are true eccentrics. Now that I think of it, most everyone I know is an eccentric. Probably most of you reading this are too. :savewave:
 
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