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Coax idea

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Coax idea

Unread postAuthor: Someone89 » Wed Nov 21, 2012 8:22 pm

Evenin' all.

Came up with this idea for a coaxial arrangement whilst wondering with to do with my spent 88g Co2 Cartridges

Image

The socket will have to be a 1.5" socket which is a couple of mm wider than the cartridge, so am planning to just fill it with epoxy to seal/attach it. I've designed it with bolts through the cartridge/socket just to give something extra for the epoxy to grip to on the cartridge, and extra peace of mind that it wouldn't go flying off at high pressure. Would then use threaded fittings to attach the barrel.

Also thinking of drilling holes in the piston and leaving the rubber sealing face only loosely attached to the piston with a couple of bolts or something so it acts as a sort of check valve.

What kind of pressures would you guys be happy using a coax like this to?
I've more than half a mind to have a more extensive read of the hybrid section and give that a go if this would be strong enough.
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Re: Coax idea

Unread postAuthor: jackssmirkingrevenge » Thu Nov 22, 2012 1:58 am

Someone89 wrote:What kind of pressures would you guys be happy using a coax like this to?


If the epoxy is well done I would have no trouble trusting this with 1000 psi.

I'm not too sure about your front endcap though, I would prefer to use an internal endcap cast with epoxy.

If you can make the piston a close fit, I wouldn't bother with o-rings or making a check valve.

I've more than half a mind to have a more extensive read of the hybrid section and give that a go if this would be strong enough.


The problem you would have is the ignition what with all the metal. In my mini piston hybrid I used the barrel as a contact point:

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Unread postAuthor: sagthegreat » Thu Nov 22, 2012 9:05 am

How does 1 cast an epoxy endcap, and also wont it shatter like glass?
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Unread postAuthor: jackssmirkingrevenge » Thu Nov 22, 2012 9:21 am

sagthegreat wrote:How does 1 cast an epoxy endcap, and also wont it shatter like glass?


http://www.spudfiles.com/forums/epoxy-c ... t8916.html

As to it shattering, it won't if done well.

All these high mix hybrid prototypes have epoxy endcaps.
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Re: Coax idea

Unread postAuthor: Someone89 » Thu Nov 22, 2012 1:38 pm

jackssmirkingrevenge wrote:
I'm not too sure about your front endcap though, I would prefer to use an internal endcap cast with epoxy.



Ah ok, my reasoning for the socket/threaded adaptors was that it allows different barrels and it can be dismantled if it doesn't work, but you'd recommend ditching them and just plugging the end with/casting the barrel in epoxy, if I've understood that right?
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Unread postAuthor: jackssmirkingrevenge » Fri Nov 23, 2012 2:10 am

I would normally advocate keeping diameters small when you're dealing with high pressure, I'm not saying the socket idea wouldn't work, but it needs to be well done with good epoxy. Care to draw a sectioned diagram of how you are planning the socket/cartridge join?
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Unread postAuthor: Someone89 » Fri Nov 23, 2012 1:39 pm

Image

Intention was to insert the cartridge half way into some kind of equal socket, drill holes through the cartridge and socket, bolt it on, (which is what the black and grey things are, not rocket sperm as they may initially appear) then fill the gap between the socket/cartidge with epoxy.

Just occured to me that drilling through the cartridge and socket might not be the best idea if it's going to contain high pressure. Maybe epoxying a smaller fitting inside the tube would be a better idea if I'm going to bother with the threaded fitting idea.

Didn't really think about the diameter, all my knowledge of high pressures/anything remotely relevant to spudgunnery has come from this forum within the last month or two haha.
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Unread postAuthor: jackssmirkingrevenge » Fri Nov 23, 2012 3:26 pm

Someone89 wrote:not rocket sperm as they may initially appear


:D :D :D

As I said, if it's well done it should hold well, even without the bolts.

Just occured to me that drilling through the cartridge and socket might not be the best idea if it's going to contain high pressure.


The socket will compensate for the holes, I wouldn't worry about it.

Didn't really think about the diameter, all my knowledge of high pressures/anything remotely relevant to spudgunnery has come from this forum within the last month or two haha.


let's say you have a 0.75" endcap and 500 psi. That has to take a force of around 220 lbs. If you increase that by just 0.25" to 1", the force it has to take under the same pressure would jump to 392 lbs, almost double.
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