Welding on a differential housing: Grassroots Motorsports forum: Grassroots Motorsports Magazine

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Nov. 10, 2009 11:33 p.m. Keith PowerDork

Okay, I need to stick this to that.

The housing is a GM 10-bolt from an S-10. I understand from Trans Mario's previous posts that it's nodular iron, which means it's about as easy to weld as cast iron gets.

The plan is to have a friend stick weld it. He's never welded cast before. We'll be using nickel rod. We'll pre-heat the housing good and hot with a torch before welding, then keep it hot afterwards to minimize the thermal shock. I'll probably wrap it in a welding blanket once we start to let it cool more. Obviously, lots of cleaning beforehand and I already have a good fit.

I've also heard that annealing the weld with a peen hammer will help relieve stresses. In other words, tap tap tap.

Suggestions? Comments? Sound like a good plan? I want to make sure we get this right.
Nov. 11, 2009 12:21 a.m. 2002maniac Reader

Sounds like you're on the right track. High nickel rod with a good pre-heat and slow cool down should do the trick.
Nov. 11, 2009 5:35 a.m. aussiesmg SuperDork

Sort of sounds familiar, mine was an S10 10 bolt also, and it is one thing that didn't break at the challenge

http://grassrootsmotorsports.com/forum/grm/10-bolt-rear-end/13516/page1/

I preheated the welding site until started to cherry, then stick welded the parts and let it cool slowly on a hot day.
Nov. 11, 2009 6:17 a.m. 44Dwarf HalfDork

Pre heat for at least 30 min try to heat the whole area not just the one spot. Use FORNEY's NORMA-CAST rod use DC at amp setting listed. Post heat while peening with slag hamer if you have out door sand blaster hit it with black slag media while hot. keep post heating and wrap in header wrap or burrie in hot (heated) sand. This will cool it slower.

44
Nov. 11, 2009 7:22 a.m. minimac Dork

Good plan. We used to do it often in our race car builds and never had a problem. We used a similar process to build both 3-bar and 4-bar setups. Just preheat a large area, weld, and slowly cool. Do as you plan and you shouldn't have any problems. Use a temp-stick so you don't overheat(or underheat) the housing. Any more is overkill, and needless expense and a waste of time.
Nov. 11, 2009 9:52 a.m. Keith PowerDork

Thanks guys. We'll try it Friday.
Nov. 11, 2009 11:53 a.m. benzbaron Reader

I could ask my dad about welding cast iron, I think they use stainless rod but I don't know for sure.
Nov. 18, 2009 4:35 p.m. Keith PowerDork

Follow-up: the operation was a success. They're not the prettiest welds, but they're strong and there are no cracks. Thanks everyone.
Nov. 18, 2009 4:37 p.m. patgizz Dork

looks good. i might need to do something like that.
Nov. 18, 2009 5:11 p.m. minimac Dork

That'll buff right out. Seriously, just wire wheel and paint and it'll look like the factory did it.
Nov. 18, 2009 7:18 p.m. emodspitfire New Reader

Nice Work !