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Re: Short question topic

Unread postPosted: Wed Nov 28, 2018 9:14 am
Author: wyz2285
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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?

Re: Short question topic

Unread postPosted: Wed Nov 28, 2018 9:25 am
Author: jackssmirkingrevenge
Are you pre-pressurizing the ram cylinder? Have you tried chucking it underwater to check for the location of the leaks?

Re: Short question topic

Unread postPosted: Wed Nov 28, 2018 9:26 am
Author: wyz2285
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

Re: Short question topic

Unread postPosted: Wed Nov 28, 2018 9:39 am
Author: jackssmirkingrevenge
Some reading on dynamic seals.

You might be better off with an X-ring in this case.

Re: Short question topic

Unread postPosted: Wed Nov 28, 2018 9:43 am
Author: wyz2285
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.

Re: Short question topic

Unread postPosted: Fri Nov 30, 2018 11:32 am
Author: wyz2285
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.

Re: Short question topic

Unread postPosted: Sat Dec 01, 2018 8:06 am
Author: jackssmirkingrevenge
wyz2285 wrote:Well butter me rear and call me biscuit, I did not expect this


:D

Interesting find!

Re: Short question topic

Unread postPosted: Sun Dec 02, 2018 12:07 pm
Author: wyz2285
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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.

Re: Short question topic

Unread postPosted: Sun Dec 02, 2018 7:12 pm
Author: jackssmirkingrevenge
That Trump quote describes a good 70% of the ideas expressed on this forum, present company not excepted!

Re: Short question topic

Unread postPosted: Sun Dec 02, 2018 7:17 pm
Author: wyz2285
Meanwhile ordered a PDI spring and machined a carbon fiber+SS piston and bearinged guide, gonna compare the performance with the floating oring version.

Re: Short question topic

Unread postPosted: Mon Dec 03, 2018 6:14 pm
Author: farcticox1
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:

Re: Short question topic

Unread postPosted: Mon Dec 03, 2018 6:52 pm
Author: jackssmirkingrevenge
Honestly it's much easier to find a fridge compressor...

Re: Short question topic

Unread postPosted: Mon Dec 03, 2018 7:07 pm
Author: farcticox1
I did, it died :cry:

Re: Short question topic

Unread postPosted: Tue Dec 04, 2018 7:30 am
Author: hectmarr
farcticox1 wrote:I did, it died :cry:

I also built it, and it also died! :(

Re: Short question topic

Unread postPosted: Tue Dec 04, 2018 7:33 am
Author: hectmarr
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.