Piston Material

Bob D. · **Posted:** Wed Dec 12, 2018 10:47 am

I need some input on piston material for machining replacement 5" bore steam pistons.
Rather than having castings made I plan to use Durabar. I didn't realize there were so many choices in grades of ductile iron. Any suggestions on what should be used?

https://www.dura-bar.com/products/index.cfm

Thanks,
Bob D.

Kelly Anderson · **Joined:** Tue Sep 14, 2004 7:52 am **Posts:** 2477

Paul Boschan · **Joined:** Mon Mar 14, 2011 6:45 pm **Posts:** 89

I have used Dura-Bar grade G2 gray iron for pistons up to 10" OD. I'd use it for larger, but I never had the opportunity. The material is readily available, easy to machine, and for one or two pieces, much cheaper than making a pattern and casting the part.

Bob D. · **Posted:** Wed Dec 12, 2018 2:09 pm

Thank you very much for the replies and information. G2 Dura-bar it is. I found Alro Steel as a retail source of cut to size pieces.

Bob D.

CJKlossner · **Posted:** Wed Dec 12, 2018 11:01 pm

We have had good luck with aluminum. I recently made some for an 11" cylinder that I bored 50 over and 7 1/2" that was 70 over. The aluminum does expand more so have to figure that in the clearances. It works well to replace cast iron pistons that are hollow to avoid excessive weight.

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Chris

mjanssen · **Posted:** Sat Dec 15, 2018 12:50 am

Dura-Bar G2

Bob D. · **Posted:** Sat Dec 15, 2018 9:04 am

Wow! Those pistons are beautiful. Look better than most public art installations.....
Thanks for the inspiring photo.

Bob D.