Cup Shape Piston

A place for general potato gun questions and discussions.
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jrrdw
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Sun Dec 20, 2009 8:28 pm

Try and get it centered as possible. Does that hole in the center go all the way through? Can use it to hold the seal and washer but it will need sealed with JB Weld or simular.
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RabidDuck
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Sun Dec 20, 2009 8:44 pm

no i'm going to smooth it all out tomorrow. Do you think i should fill it and try centering it better or will it work? The hole doesn't go all the way through.
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jrrdw
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Sun Dec 20, 2009 9:03 pm

See if you can work with what you have all ready, if you sand on the thicker part it will bring the hole to center. I think your doing a good job so far.
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psycix
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Mon Dec 21, 2009 9:30 am

Your paint skills are awful!
Good to see our moderator still does some spudding though. :)


There is completely no need for the channels leading to the barrel, just make the hole larger, like JSR's design.
JSR's design also uses a bolt to hold the sealing face, which is more reliable then glue.
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jrrdw
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Mon Dec 21, 2009 9:42 am

psycix wrote:Your paint skills are awful!
For 2 minutes time, that is awsome not awful. Now if I used MS Paint on a regular basis, well......

If your any better, inlighten us with your paint skills. :wink:

Do not confuse this post with anything other then a attempt to trick you into doing a better job of creating this diagram then I did, it is indeed exactly that :D .
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roboman
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Mon Dec 21, 2009 11:22 am

I would suggest a forstner bit for the center hole....much easier to use (in this case) than a holesaw.
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jeepkahn
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Tue Dec 22, 2009 4:27 pm

AHEM... here's some pics of 2" and 4"....
Attachments
4" cup/piston
4" cup/piston
t_golfgun_piston_166.jpg (20.62 KiB) Viewed 2443 times
2" piston/cup
2" piston/cup
t_inside_of_piston_145.jpg (24.36 KiB) Viewed 2443 times
My Cannons can be found by clicking the following link.
http://www.spudfiles.com/forums/viewtop ... tml#256896
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jrrdw
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Tue Dec 22, 2009 4:44 pm

When did you build these?
jeepkahn
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Tue Dec 22, 2009 5:52 pm

jrrdw wrote:When did you build these?
the 4" was for dd-1(about a year ago), and the 2" was a coupla months before that...
My Cannons can be found by clicking the following link.
http://www.spudfiles.com/forums/viewtop ... tml#256896
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POLAND_SPUD
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Tue Dec 22, 2009 8:15 pm

lol jrrdw & JSR
two spudders one cup :D

I've got to admit jrrdw that you paint skillz are even worse than mine... and yeah I agree with psycix that jsr's idea is better and simpler to implement (unless I am missing something?)
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jrrdw
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Tue Dec 22, 2009 8:20 pm

Poland_Spud wrote:lol jrrdw & JSR
two spudders one cup

and our cup runith over! :P
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jackssmirkingrevenge
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Tue Dec 22, 2009 11:46 pm

POLAND_SPUD wrote:two spudders one cup shaped piston
OH FFS!!! And I though2 girls 1 CPU was bad!

:D :D :D
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RabidDuck
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Wed Dec 23, 2009 8:38 pm

haha update here. needs some more smoothing out but it's getting there. It's kinda hard to do Jrrdw's design now that i sanded out too much so i think it maybe just be a regular cup piston with out all the vent holes and such but here are the pictures. I sanded this out while standing outside while it was snowing, brrrrrrrrrr.

http://img163.imageshack.us/gal.php?g=piston21001.jpg
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jrrdw
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Thu Dec 24, 2009 1:41 pm

As long as you get your sealing surface flat as can be, this should work.

The question seems to be how well.......
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Willdebeers
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Thu Dec 24, 2009 1:49 pm

I always had a problem with sealing, and I found that if you mark off the line you want to cut, then sand it off after, you usually get a relitivley flat sealing face.


Of course, I just use my lathe :D
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