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Short question topic

A place to ask general spud cannon related questions.
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Re: Short question topic

Unread postAuthor: wyz2285 » Wed Nov 28, 2018 9:14 am

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Well here is why I'm interested in it. Had a HPA system but I'm trying to ditch the tank.
So they are only using two o-rings too... Wonder if it's free float or snug fit?
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CpTn_lAw wrote::D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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Re: Short question topic

Unread postAuthor: jackssmirkingrevenge » Wed Nov 28, 2018 9:25 am

Are you pre-pressurizing the ram cylinder? Have you tried chucking it underwater to check for the location of the leaks?
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hectmarr wrote:You have to make many weapons, because this field is long and short life
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Re: Short question topic

Unread postAuthor: wyz2285 » Wed Nov 28, 2018 9:26 am

yes it needs a bit of pressure around 20 psi.
No leaks if the parts don't move... once it moves I loose 10 fps per shot
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CpTn_lAw wrote::D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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Re: Short question topic

Unread postAuthor: jackssmirkingrevenge » Wed Nov 28, 2018 9:39 am

Some reading on dynamic seals.

You might be better off with an X-ring in this case.
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hectmarr wrote:You have to make many weapons, because this field is long and short life
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Re: Short question topic

Unread postAuthor: wyz2285 » Wed Nov 28, 2018 9:43 am

Quick update: The seal got better after I used slightly larger o-rings.
So I'm gonna redo the aluminium part, make it squeeze the o-rings a bit, also gonna change the rear to thread mount instead of just o-rings slide on. If this works would be great, the thing is real crisp to shoot and quiet.
The articule says dynamic seals do leak, so what's the service time of a gas ram? Would be ironic since one of the main advantages advertised is no power lose over time compared to springs.
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CpTn_lAw wrote::D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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Re: Short question topic

Unread postAuthor: wyz2285 » Fri Nov 30, 2018 11:32 am

Well butter me rear and call me biscuit, I did not expect this
This would cause the need to increase the pre charge pressure and make the leak less noticeable.
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CpTn_lAw wrote::D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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Re: Short question topic

Unread postAuthor: jackssmirkingrevenge » Sat Dec 01, 2018 8:06 am

wyz2285 wrote:Well butter me rear and call me biscuit, I did not expect this


:D

Interesting find!
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hectmarr wrote:You have to make many weapons, because this field is long and short life
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Re: Short question topic

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Re: Short question topic

Unread postAuthor: wyz2285 » Sun Dec 02, 2018 12:07 pm

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Diminished the leak, however the friction of the o-rings became problematic, the FPS actually rises a little when the pressure starts to drop before start diminishing.
FPS is also lower than the floating o-ring version, the piston is moving slower.
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CpTn_lAw wrote::D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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Re: Short question topic

Unread postAuthor: jackssmirkingrevenge » Sun Dec 02, 2018 7:12 pm

That Trump quote describes a good 70% of the ideas expressed on this forum, present company not excepted!
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hectmarr wrote:You have to make many weapons, because this field is long and short life
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Re: Short question topic

Unread postAuthor: wyz2285 » Sun Dec 02, 2018 7:17 pm

Meanwhile ordered a PDI spring and machined a carbon fiber+SS piston and bearinged guide, gonna compare the performance with the floating oring version.
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CpTn_lAw wrote::D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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Re: Short question topic

Unread postAuthor: farcticox1 » Mon Dec 03, 2018 6:14 pm

Anybody tried building a piston compressor? I have a 2" stroke pneumatic cylinder rated at 250psi so was going to see if I could generate 200psi :idea:
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Re: Short question topic

Unread postAuthor: jackssmirkingrevenge » Mon Dec 03, 2018 6:52 pm

Honestly it's much easier to find a fridge compressor...
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hectmarr wrote:You have to make many weapons, because this field is long and short life
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Re: Short question topic

Unread postAuthor: farcticox1 » Mon Dec 03, 2018 7:07 pm

I did, it died :cry:
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Re: Short question topic

Unread postAuthor: hectmarr » Tue Dec 04, 2018 7:30 am

farcticox1 wrote:I did, it died :cry:

I also built it, and it also died! :(
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Actually I'm planning the improvised, and improvising what's planned!
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Re: Short question topic

Unread postAuthor: hectmarr » Tue Dec 04, 2018 7:33 am

jackssmirkingrevenge wrote:Honestly it's much easier to find a fridge compressor...


I made one with a refrigerator compressor motor. Testing, it arrives without problems at 25 bar ... I exploded 4 mm polyurethane hoses. It really works.
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