On Thu, 11 Apr 2019 14:58:41 -0400, Leon Fisk
wrote:

On Thu, 11 Apr 2019 14:37:49 -0400
Clare Snyder wrote:

snip
For manifold repair Braze is often insufficient due to operating
temperatures. I like to pre-heat then tig with stainless steel wire.
Drilling a small hole at the end of the crack if not cracked through
helps keep the crack from running away on you as you chase it with the
weld

Yeah, I haven't had to try repairing one but what you mention
concerning the heat produced in a working manifold has crossed my mind.

I welded a small cast part for my neighbor with Forney Noma-Cast rod.
Looked like crap but held together for a couple years. He sold it
recently, so I don't have to worry about re-welding it again
I brazed - and then rebrazed, several Chrysler slant six exhaust
manifolds in my younger years - never successfully - on my 63 Valiant
170. To be fair, the little critter wasn't technically stock, putting
out 206HP to the rear wheals through it's unmodified torqueflyte 3
speedautomatic (at 6500RPM) so the exhaust temperature was possibly a
bit higher than normal -

I have also had several manifolds repaired by tigging with stainless -
and have not had any of the repairs fail.

I have repaired a lot of exhaust PIPES with brazing as well - and only
repairs farther back than about 3 feet from the manifold have proven
reliable