Welding Sachs cases

[Carl Hill]

I need to know if there is a "secret " to welding Sachs engine cases. I took one to a local welding/fabrication shop a few years back and they told me it couldn't be welded and that is wasn't "regular aluminum". I want to restore the Berkshire that I got when I was 13 (many decades ago) and would prefer to keep it as original as possible.
Thanks

[Doug Knight]

Are you trying to repair from a thrown chain? Clutch cover? Mag cover and or the case? The covers are easier and the engine case would require a little more involvement as in preheating and post heating. If it's the cases, they may need to be split and the gears removed before welding.

The cases are cast aluminum, normally porous. Nothing special alloy aluminum. I would use 5356 or 5556 as tig filler. I don't recommend 4043 as it's a braising alloy. Jerry Birky ten years back use to do these type repairs. There a lot of tricks in doing these types of repairs. YMMV

[Carl Hill]

No thrown chain. The ignition cover was removed many years ago and with the engine being moved from place to place over the years it looks like something may have been dropped on the mating surface of the crankcase. No big damage but it does need fixed.
Going to finish tearing it down completely. Sounds like heating the cases my "sweat" the oil out of the porous aluminum? If this is true maybe I should heat several times prior to getting it welded?
Thanks

[Dale Fisher]

Rick Bennett and others seem to be able to weld them up effectively.

[Carl Hill]

Beautiful!
Mr. Bennett are you out there???

[Daniel P. McEntee]

   The main issue with welding crank cases is oil !! All metal is porous to a certain extent, and cast aluminum is almost like a sponge. I have learned through the years that it just takes a lot of patience when it comes to welding castings. I have tried preheating with a torch and such in an attempt to cook pout the oil that gets absorbed but it's never worked. I don't have access to an oven but I doubt they would get hot enough. Aluminum is different that steel in that it does not change color as it gets hot. You have to get cast aluminum close to what I think they call it's eutectic point, the temperature when the molecules of the metal really expand and change state. Every metal has this. The best thing I have found is to just start in at a spot, and as the oil cooks out, just stop, clean everything with a wire brush again, and start over. You hay have to repeat this several times until it will just suddenly stop at that point and you will see the puddle get glassy and shiny and start to form. Once you get fresh filler rod added, just work your way along until you get the first layer in. Once you get the "foundation" put down, it will weld normally as you do the build up or fill things in. With big holes, you can back the hole up with a piece of steel to work off of and support the new metal. It just takes time and a good understanding of what is going on. A typical welder at a local shop might not ever get to do enough of this type of work to get experience at it, or just doesn't want to spend the time. Rick photos of the case he repaired for Paul are great and show great work and what is possible.. After everything is welded, the next trick is to get it all machined and ground down to a finish size, and that takes time also. Don't ever let anyone say that it's junk metal or pot metal or the "different" kind of aluminum. It's just full of oil!
  Type at you later,
  Dan McEntee
 

[Carl Hill]

Thanks Dan

[Rick Bennett]

Yes,I am here.
440-417-8094
If I don't answer, leave a message. My phone coverage is not so good unless I stand near my drill press.

[Carl Hill]

I ended up buying a different set of cases. Thanks anyway.