Posted by Vaughn [172.68.141.97] on Saturday, January 30, 2021 at 10:14:12 :
In Reply to: Re: Broken manifold, why? posted by Greg Coffin [162.158.74.4] on Saturday, January 30, 2021 at 09:50:40 :
Brazing is ok, but doesn't expand/contract the same as cast iron which can cause new cracks. Taking the manifold off and brazing it with the pieces matted together, without the gap, will subject the manifold to the same forces. If you keep the gap when welding, you should be able to rap again without issues.
If you don't have a distributor in your area for MG rod, contact the company and tell them you would like to try the product, but don't get rods larger than 1/8, 3/32 is best to keep the temperature down when welding which is important to cast iron. I've used MG250 to repair cracks in heads and exhaust manifolds, 210 works fine too.
Most important piece is grinding the impurities off the cast iron till you get clean metal. The rod flows the same as using a 6011 or 6013 rod, it's really nice to weld with. It's rather expensive, but well worth it when it comes to welding cast iron.