we could not penetrate when trying to weld the hangers...im unsure of what blend of gas we used.

Since the muffler is stainless and the piping is mild, I used 309L and argon only. I brought my tank of Mix 75/25 but was too lazy to hook it up. or maybe I did. I forget.

Straight argon is for aluminum

maybe i used mix then. i'd have to go look at which bottle has the cap removed.

it's possible I bought the straight argon for aluminum welding for fun.

Whatever gas you are using the welds look good.

In your pics you have some pretty good gap in the tubes. The recent exhaust work I have done I butted the tubes together. I found I was able to turn the heat up a bit and get better heat penetration without burn through. I figure this is okay since exhaust is not structural. What are your thoughts.

Kind of off topic, But I think I am going to build a second exhaust with a smaller muffler and build as straight a system as possible. Then I will take both exhaust to the dyno to test

the image of my welds was a test tube.

Pipes were butted up good when we tacked them:

http://www.boostedmiata.com/gallery2...1/DSC_0026.JPG

again click to see full size.

Ideally you do want them to butt up flush and then chamfer the edges so you're welding in the vee to help penetration... but when you're doing a sloppy garage job and it's a humid 85 degrees, you work fast with what you have.

also, I had to spend some time filling brain's burn through hole when he was learning to weld.

I thought we weren't going to talk about that.

Yeah I see it now, the tubes are butted tight. Chamfer would be best, but we are talking about 16 gauge, I would be afraid of burning through.

this we did, look here again:

http://www.boostedmiata.com/gallery2...2/DSC_0013.JPG

we beveled, "chamffered," the edges with the flat side of the chop saw.


or would chamffering be doing that to one pipe and having the other sit overtop?

Nice work, I was lazy, just butted the tubes together. Worked fine on my last exhaust, but not the best way to build it.