Piston

ShowNoMercy · Tue Apr 24, 2007 9:23 pm

I was wondering what the biggest piston valve someone has built as of now. I want to build a really big one and was wondering if anyone has any advice on it. I was thinking somewhere around a 4 inch piston but I am not sure whether its worth it.

Velocity · Tue Apr 24, 2007 10:08 pm

I have built a 4" piston valve with 3" porting... this is the largest piston valve that I have ever built. Within a few months to a year, I hope to rebuild it and improve it.

Honestly, once you get into the 4" porting valves in a 6" tee, it just gets annoying (this is not talking about coaxials, which are an entirely different animal). The fittings are too expensive, the pressure rating is too low, the pieces are too hard to find, and if you mess up, your screwed.

I have plans to build a 4" porting valve in a 6" tee... I could buy all of the parts off of mcmaster.com for under $200; however, for the reasons stated above, I do not plan to do so.

If you build one, you are going to need a pretty big pilot valve; I would recommend a good sized piston valve or a 1.5" QEV.

ShowNoMercy · Wed Apr 25, 2007 5:58 am

Well I think I have access to rather large steel stock and I have a few lathes and mills to work with so I was hoping to build it that way, but if the results start to diminsh then I probably wont. I guess I woudlnt really have a cannon that actually needed one that size anyway.

AmYisroelChai · Wed Apr 25, 2007 8:39 am

ShowNoMercy wrote:Well I think I have access to rather large steel stock and I have a few lathes and mills to work with so I was hoping to build it that way, but if the results start to diminsh then I probably wont. I guess I woudlnt really have a cannon that actually needed one that size anyway.

No No No... Dont get discaureged. The limits in larger fitting is with PVC only because the PSI rating is super low. With steel -go for it!!!! You can build a monster cannon that way!!

Build a custom piston by cutting down 6" pipe or what not.