Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 60 users online :: 6 registered, 0 hidden and 54 guests


Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

Registered users: anello, Bing [Bot], Google [Bot], Google Adsense [Bot], MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

3 inch piston help

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
Sponsored 
  • Author
    Message

3 inch piston help

Unread postAuthor: cannon monkey » Wed Apr 13, 2011 9:57 pm

Hey guys Im in need looking to build a new toy but I don't know what to use for a piston I'm looking to fit into 3"pipe bout 2-4 inchs long any ideas

Thanks in advance,
Monkey
  • 0

most big random like i ever seen

cannon monkey
Major
Major
 
Posts: 399
Joined: Sun Sep 07, 2008 10:50 am
Location: usa FL
Reputation: 0

Unread postAuthor: Gaderelguitarist » Wed Apr 13, 2011 10:09 pm

Make one from wood, or make one from pvc fittings.
  • 0

so many muchness
User avatar
Gaderelguitarist
Colonel
Colonel
 
Posts: 580
Joined: Sat Aug 16, 2008 9:56 pm
Location: Columbia, MD
Reputation: 0

Unread postAuthor: squidchicken » Wed Apr 13, 2011 11:23 pm

yea wood or pvc fittings, anything solid and not too heavy, could maybe make a huge fibre glass piston
  • 0


squidchicken
Specialist
Specialist
 
Posts: 41
Joined: Sun Oct 10, 2010 3:55 am
Reputation: 0

Unread postAuthor: cannon monkey » Thu Apr 14, 2011 12:02 am

I tried 2 inch couplings their too small and there no stores near by with 2.5 anything any ideas??? :(
  • 0

most big random like i ever seen

cannon monkey
Major
Major
 
Posts: 399
Joined: Sun Sep 07, 2008 10:50 am
Location: usa FL
Reputation: 0

Unread postAuthor: Technician1002 » Thu Apr 14, 2011 12:26 am

Fiberglass is fragile. I would recommend something with much higher impact resistance. PVC is too brittle too for that size. I had a couple of cannons that used inverted pipe caps for pistons. The Mouse Musket used a 1 inch piston and the Dragon used an inverted 2.5 inch pipe cap. The larger pipe cap is a little large to fit in a 3 inch pipe. I had to machine the piston and pipe on a lathe to get them to fit. Both cannons using PVC pistons broke them.

If you have access to a lathe, UMWHDPE or HDPE round stock from McMaster would work well. It has good impact resistance.
I use that in my newer QDV cannons and it is holding up very well.

HDPE has a mass slightly less than water. It makes great light pistons. They are less than 1/4 the weight of steel.
Image
  • 0

User avatar
Technician1002
Chief of Staff
Chief of Staff
 
Posts: 5190
Joined: Sat Apr 04, 2009 11:10 am
Reputation: 14

Unread postAuthor: cannon monkey » Thu Apr 14, 2011 6:38 am

I was lookin into the hdpe stuff but it cost so much
  • 0

most big random like i ever seen

cannon monkey
Major
Major
 
Posts: 399
Joined: Sun Sep 07, 2008 10:50 am
Location: usa FL
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Thu Apr 14, 2011 8:51 am

Image
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Sponsored

Sponsor
 


Unread postAuthor: c9d » Thu Apr 14, 2011 9:49 pm

I went out and bought a set of white HDPE cutting boards, a 3" hole saw, a round rubber flap valve for a toilet, some rubber gasket making material, tennis balls, a proper length bolt with nylon locknut, and all purpose cement. Made the 3" barrel sealing piston for my coax cannon, no problem.
  • 0


c9d
Specialist
Specialist
 
Posts: 44
Joined: Sun Nov 04, 2007 12:56 am
Reputation: 0

Unread postAuthor: cannon monkey » Fri Apr 15, 2011 5:12 am

I just got 3" hole saw but it not right size :(
  • 0

most big random like i ever seen

cannon monkey
Major
Major
 
Posts: 399
Joined: Sun Sep 07, 2008 10:50 am
Location: usa FL
Reputation: 0

Unread postAuthor: motorfixer1 » Fri Apr 15, 2011 5:39 am

Go for the HDPE stock from mcmaster like tech said. If you want to play you gotta pay.
  • 0


motorfixer1
Sergeant
Sergeant
 
Posts: 91
Joined: Wed Jul 07, 2010 5:28 pm
Reputation: 0

Unread postAuthor: MochaDesign » Fri Apr 15, 2011 8:11 am

Hockey pucks fit 3" perfectly. We haven't encountered any problems using them yet, and the best part is that you don't need any gasket material. The rubber face of the puck should seal just fine at ~70-110 psi (from our testing).

-John and Andrew
  • 0


MochaDesign
Private
Private
 
Posts: 1
Joined: Wed Apr 13, 2011 4:42 pm
Reputation: 0

Unread postAuthor: Labtecpower » Fri Apr 15, 2011 8:25 am

but he doesn't want to spend money :roll:
  • 0

"ñøw mÿ šįg šüçkś!"
User avatar
Labtecpower
Major General
Major General
 
Posts: 1267
Joined: Sat Feb 20, 2010 6:38 am
Location: Herb Island
Reputation: 7

Unread postAuthor: Technician1002 » Fri Apr 15, 2011 9:29 am

In related news, I want a Bugatti Veyron, but don't want to spend the money. :(

If you have a drill press you can make the right size.
http://www.spudfiles.com/forums/tutorial-making-a-small-o-ringed-piston-on-a-drill-press-t21740.html
  • 0

User avatar
Technician1002
Chief of Staff
Chief of Staff
 
Posts: 5190
Joined: Sat Apr 04, 2009 11:10 am
Reputation: 14

Unread postAuthor: Labtecpower » Fri Apr 15, 2011 10:46 am

SO.... If you don't want to spend money, stop asking, use your brains, and be creative! you should be able to find something suitable for a piston.
  • 0

"ñøw mÿ šįg šüçkś!"
User avatar
Labtecpower
Major General
Major General
 
Posts: 1267
Joined: Sat Feb 20, 2010 6:38 am
Location: Herb Island
Reputation: 7

Unread postAuthor: mark.f » Fri Apr 15, 2011 11:00 am

Hmmm, jack has a fairly good suggestion. Fillers such as open-cell foam could make the piston lightweight and reduce epoxy consumption as well.

I agree that paying NOTHING for a piston is a little optimistic. Even a deodorant can piston (a la MrCrowley) requires rubber gasketing and some hardware (and if you use roll-on you're stuck buying a deodorant can as well).
  • 0

User avatar
mark.f
Donating Member
Donating Member
 
Posts: 3464
Joined: Sat May 06, 2006 11:18 am
Country: United States (us)
Reputation: 21

Next

Return to Pneumatic Cannon Discussion

Who is online

Registered users: anello, Bing [Bot], Google [Bot], Google Adsense [Bot], MSNbot Media, Yahoo [Bot]

Reputation System ©'