Practice Header Fabrication Materials

[tkelly27]

Your local steam fitters and home depot will carry schedule 40 mild steel pipe. A lot of people like the look of SS, but sch 40 mild steel is plenty strong enough. It's about $5 a 90* bend at the steam fitters, and $? really cheap/foot at home depot. Comes out a lot cheaper, and you can actually use the piece you've made. Also, easy to weld, much less warpage.

I made the oval shape in a vice. With my sch 40 pipe I found that I reached a point where I just could not form it any further. I even hit the vice handle and it would not go further. We talked to the metallurgist at my dad's work and it turns out a simple wood fire is enough to re-heat treat mild steel enough to make it pliable again. Stick it in until you think it's good and hot, let it cool in the air until you can touch it, then go back to squeezing it. I imagine you could do it in a press too.

For your first manifold, if you can start with something someone else has already done for cheap, go for it. The rams horn manifold that the honda guys make would be sweet to see made DSM style.

There will probably be a few built at my house in the coming year, I'll have to post pics.

 

[TheBoz]

Also as tkelly27 said, stainless likes to move a lot when it is heated up. You will need to also have a torque plate. I used a piece of 1inch steel to mount the flange to while it was being welded. That is a very critical part. Also the collector was the hardest part for me, be sure to check hood clearance, you can run out of room really quick.