Exhaust pipe coating

[White Lincoln]

Question:
Now that I have my mufflers welded to the exhaust pipe, I decided I would wire wheel that ugly orange / beige color from the exhaust. Since I did this, do I need to spray the pipe with high temp engine / exhaust paint or coat the metal with something else? I may have just stripped a protective coating off the exhaust.

 

[KevinVarnes]

If that is 409 stainless I'd just leave it alone. Even if it is aluminized it will still probably last 100 years where you are.

 

[White Lincoln]

If that is 409 stainless I'd just leave it alone. Even if it is aluminized it will still probably last 100 years where you are.

It is OEM exhaust from a 95 t-bird.

Thanks Kevin!

 

[Grog6]

stock is stainless, so polishing it wont hurt. it turns brown with heat, so it will go back to the brown color eventually.

 

[AdamG]

Stock is not stainless on tbirds, maybe it is on mark viiis but I've seen plenty if rusted out exhausts on these cars. In New Mexico you might be fine but I'd still put a coat of high heat exhaust paint on it to just help it.

 

[KevinVarnes]

From what I have seen the stock systems were 409. The exhaust system on my old '92 had 260k miles and was 14 years old before the rear shock towers rusted out and I had to junk the car. Exhaust was still in good shape. No way aluminized would last that long up here. I remember on our old '90 Taurus one of the muffler clamps rusted off from the pipes, but the pipes were still in good shape. I don't know when most/all OEMs changed over to stainless, but I'm guessing late 80's early 90's. Even the stock exhaust systems on my Saturns are 409.

 

[theterminator93]

That jives with what one of the Lorain assembly line guys (his job for a time was installing the exhausts on our cars) told me years ago - he said they were stainless.

 

[XR7-4.6]

agreed, I can’t speak for earlier models but by 94 it’s definitely 409 stainless. Rotten hardware are maladies to the stock system but the pipes are always solid.

I’ve seen first hand what happens to aluminumized pipes in the Chicago area, they last only a few years.

 

[dDUBb]

What type of welding wire was used ? Thats where it might rust. On the inside.

 

[XR7-4.6]

What type of welding wire was used ? Thats where it might rust. On the inside.

This was the mid portion of my old exhaust, the welds were indeed worse (as you can probably see by the hose clamp patch I made lol) but the previously aluminized pipes beyond were paper thin in places



The magnaflow muffler looks rusty but was 409 stainless and actually lives on on @97 30th s car. Those pipes crumbled to dust as I stuffed them into the garbage can

 

[dDUBb]

It's also evident where the hanger was welded. That would be the result of using non stainless wire on stainless. It will weld, but the corrosion resistance is not equal and paint might take care of that on the outside - but not inside if the welds fully penetrated; and then add some slightly acidic exhaust water.

 

[White Lincoln]

I think this exhaust is stainless as it still looks great after some 30 years.

 

[White Lincoln]

I do have a welding question....

I did a rooky mistake and welded the muffler to the exhaust AFTER tack welding it in place and dropping the exhaust to finish the weld. One mufflers tack welds broke, throwing it out of position. I went ahead and welded both mufflers, but one side is off by more than an inch or so. I need to either:
1. cut a slit, bend the pipe, weld a patch over the cut out,
2. cut the muffler off and use a scrap sleeve to weld it back together after everything is mounted, or...

Any other clever ideas to rearrange the muffler to fit better and weld it back together, after mounting everything?

(yes, there is a lot of grinding that will need to take place to flatten the surface)

 

[Grog6]

When I had the muffler shop redo Lazarus, They told me it was stainless, and their welder wouldn't touch it. They wanted to reuse something, and couldn't. I bought mbs aluminized for the other cars. 2.5 sounds way better on a 4.6 .

 

[dDUBb]

2. cut the muffler off and use a scrap sleeve to weld it back together after everything is mounted

Cut that section out and start over.

 

[White Lincoln]

Cut that section out and start over.

Thanks dDub.

 

[dDUBb]

Just a couple thoughts ..

If the tack weld broke at the pipe end - you're not getting penetration. Need to turn up the heat (amps) The weld bead will stick but it's more like an adhesive bond versus a cohesive bond.

When we tack weld pipes together - usually they are done in parallel and we hammer a wedge into the gap perpindicular to alter the alignment - in other words, the tack welds should have the ability to bend to an extent - they can be broken, and this shoukd happen at the center of the tack, not where the tack is welded to the pipe.

Wire type for stainless .. I'm not sure you're using the best quality wire for the weld you are attempting - what exactly are you using ?

Welding is just like painting .. 80% of the work is in preparation - cutting, chamfering, alignment, cleanup of slag, etc ..choosing coupling fittings that fit tightly over each end is important, anybody can fill a gap but it's not good work practice / means and methods of the trade - I'd rather hammer it flat to make a nice lap joint.