Welding Tips and Tricks

TRACKRANGER wrote:It may not

An issue will be distorion/warping. Maybe get some preheat into it with the Oxy/Acetylene.

Presuming it is aluminum, I would try to light-up on one of the stud hole lugs, and see if you can form a puddle. You'll need to hit it fairly hard, as you want to see a puddle in about 3 seconds.

Have you had much experience with this type of work? It'll certainly be a little more challenging than welding some nice 1/8" or 3/16" thick sheet.

Also, that joint preparation doesn't look anywhere clean enough. Scotchbright pad or similar, clean SS wirebrush etc will help. Get underneath the casting surface to expose fresh metal first before you try to weld.

dave powelson wrote:

LtBadd wrote:My experience tells me if I try this the base metal is going to spit and turn black, any suggestions or ideas are welcome."

What is the part?
intake?
exhaust?

There's scant detail in the pics. Some closer detail is needed.

Is that a long crack running next to a cutout area with a thin patch plate sitting on it?

What welder do you have to use?

I believe it'a an exhaust, I'll talk to the customer. It's not a crack, in the first pic (1347a) you can see the underside of the "patch" sitting in the cutout area. What looks like a crack in the second pic is the gap you can see in the 1st pic. The patch cuts across the inside diameter and you can see a slither-like gap area.

I have a Dynasty 350 to weld with.

dave powelson wrote:'I believe it'a an exhaust, I'll talk to the customer. It's not a crack, in the first pic (1347a) you can see the underside of the "patch" sitting in the cutout area. What looks like a crack in the second pic is the gap you can see in the 1st pic. The patch cuts across the inside diameter and you can see a slither-like gap area.'

'I have a Dynasty 350 to weld with'.

And the reason for this thin patch in the first place is?
It's a custom job by the customer, a turbo install for a BMW

And a thicker patch isn't being considered or a formed, thicker plate is being considered, becuz?
Clearance is needed in this area due to custom install of turbo

And the cutout corners have to be dead sharp? (Stress risers)
Again, done by the customer

Is this a marine water jacketed exhaust?

And currently, the mating flange areas all check flat with a straightedge?
(I do that immediately, in front of customer, with any manifold.)

If the hole being patched is due to exhaust burnout--the material that is degraded from this oxidation needs to be removed,
while first inspecting the interior adjacent area for signs of 'graininess'. Try to weld to heat oxidized, altered cast AL works poorly. The real condition of the manifold and the expectations of the owner need to be determined.

http://weldingweb.com/showthread.php?45 ... ost4996441

Since you've got a 350, the above link may help you in dealing with 'bad' AL. The interior patch area needs to be cleaned, bead blasted/light carbide burred--well, to minimize carbon and exhaust crap outgassing during welding. The inside of the patch weld area should be welded in addition to the outside or at least back purged.
Maxal 4943 filler suggested.

I do have this filler

The casting is 'restrained' and will resist the heat expansion, then subsequent weld cooling contraction. If it's a water jacketed manifold (which I suspect), then this adds problems to any post weld cracking. The optimum solution for this is a throughout oven preheat to 350˚F, weld out some, back in oven to 350, weld more, then oven slow cool. This significantly helps stop AL cast head and manifold post weld cracking. That's the SOP which Peter Sattler--Castweld on WW uses.

The selection of the patch material needs discussion.
I'd regard a repair like this as only a temporary fix. Jacketed exhausts have a finite life.
Assume that the manifold will require competent surfacing back to flat after the work and notify customer in advance, before taking the work on.