I'm just about finished cleaning up the manifolds I got this spring (thanks Rugrtucker).

When I was picking off the springs etc. prior to degreasing the exhaust manifold, I noticed that the welds from the butterfly to the shaft were weak.

I managed, with minimal Dremmeling, to remove the flap from the shaft, which allowed me to remove the shaft/wheel and thoroughly clean the shaft and bores.

I am getting ready to paint and reassemble everything.

This is more a welding question than anything else, but I'm asking the question here, and not a welding forum, because you guys are all familiar with these flaps, and many of you weld.

I am only just learning to weld (MIG for body work, so far).

My MIG is 90 amps/120v and can weld up to 3/16 when plugged into a 20 amp outlet.

Is it possible to use my welder, or am I going to have to get someone to stick weld it on (or apply some other process with a heavier welder than mine)?

I'm guessing if I preheated the shaft w/a plumber's torch it could be done, but I really have no idea. (none of the literature or media I have reviewed in trying to teach myself to weld has addressed MIG welding dissimilar thicknesses of metal).

I'm also entertaining drilling/tapping machine screw theads in the shaft and installing like a choke or throttle plate. (I suspect the heat cycling makes this a bad idea, and it is why they were welded to begin with).

Please advise.

Also, I plan to use VHT Flameproof cast iron paint. I had removed the surface rust with prep&etch and there is a haze of what I guess must be zinc phosphate. Should I grind/brush/sand that all off, or does it even matter?

Has anyone ever used the VHT clear directly on thier manifold? (VHT reccomends primer, so that seems like a 'no,' but maybe they are just trying to sell an additional can of paint.)

Any input is greatly appreciated as allways.

I used this on my headers and stock manifolds, after cooking them at operating temperature both are a nice shade of ash grey (headers and manifolds were red to start with...)

FYI.

-D.Idiot

It sounds to me like your welder is more than adequate, it not like we're building bridges here so I wouldn't worry about it. Just have the parts cleaned up nice and positioned properly then I'd tack the flap on by starting each bead on the thicker part, moving quicker over the thin part to finish. A few tacks should do it. No preheat needed. You could always practice on similar scrap pieces to find decent welder settings and play with the motion. The judges won't be able to see it so no points lost on the concourse.

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1966 Coronet Deluxe

thank you.

I'd do a small tack first then test the valve through its full range of travel before "finish" welding. Nothing sucks quite like doing a great weld then finding out it's in the wrong place- hits something, or is in backwards, etc. A couple 1/4-1/2" welds will hold fine. Be sure your ground clamp is secured to the flapper shaft of counter weight.

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63 Valiant Wagon
225 - 4 bbl

Also disengage the metal coil from the prong it's attached to on the manifold, there have been instances in the past where somebody has welded the flap and 'sprung' the spring, that way it can expand during the welding process instead of trying to expand and you are keeping the flap closed.