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Micarta Piston

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.
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Micarta Piston

Unread postAuthor: Davidvaini » Sat Jun 20, 2009 3:17 pm

Just posing a question out here.


Has anyone ever made a Micarta Piston before?

how would a Micarta piston perform?


link to info about Micarta:

http://en.wikipedia.org/wiki/Micarta
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Unread postAuthor: PVC Arsenal 17 » Sat Jun 20, 2009 3:43 pm

I would imagine a piston made out of micarta would need a ton of lubrication... that's stuff's usually pretty textured. Although I'm only familiar with micarta being used on knife handles, so it may only be textured in that application. Is it smooth normally?
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Unread postAuthor: Hotwired » Sat Jun 20, 2009 3:44 pm

Hum, so that's what the stuff circuit boards are made of is called.

No better than a HDPE one?
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Unread postAuthor: velocity3x » Sat Jun 20, 2009 3:52 pm

David,
I made the piston for my cannon from "Delrin" (aka "Acetal"). It's 2.000" dia and functions flawlessly with constant use of 300 psi CO2. It isn't brittle like Micarta. It has high natural lubricity with tensile strength around 10,000 psi and compressive strength around 18,000 psi. Micarta could fracture at high pressure / cold temps or both.
<img src="http://i145.photobucket.com/albums/r240/velocity3x/44mm%20HUNGUS/44HUNGUSShuttleValve.jpg?">
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Unread postAuthor: Davidvaini » Sat Jun 20, 2009 4:14 pm

velocity3x wrote:David,
It isn't brittle like Micarta. Micarta could fracture at high pressure / cold temps or both.


Correct me if I'm wrong but Micarta can be made with epoxy and therefor it would not have those issues other than brittleness?

I'm thinking more of epoxy reinforced with fibers or fabric.

EDIT: Just thinking outside of the box. I guess what I am thinking of is more of fiber reinforced epoxy.
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Unread postAuthor: dewey-1 » Sun Jun 21, 2009 9:04 am

Davidvaini wrote:
velocity3x wrote:David,
It isn't brittle like Micarta. Micarta could fracture at high pressure / cold temps or both.


Correct me if I'm wrong but Micarta can be made with epoxy and therefor it would not have those issues other than brittleness?

I'm thinking more of epoxy reinforced with fibers or fabric.

EDIT: Just thinking outside of the box. I guess what I am thinking of is more of fiber reinforced epoxy.


David, here is a link with a good explanation of Micarta laminates:

http://www.sdplastics.com/phenolic.html

It shows properties as well as typical color chip/ grain characteristics.

I would agree what others have stated about using other types of plastic
due to their "self lubricating" properties. Examples are: HDPE, UHMW, nylon, Delrin, Teflon, and others.

Fiberglass impregnated epoxy construction is very abrasive.
For machining these materials you usually have to use carbide tipped tooling. Standard tooling will wear very rapidly and need resharpening.
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Unread postAuthor: Biopyro » Sun Jun 21, 2009 11:02 am

Personally I'd just go for HDPE. It's lighter, cheaper and has a lower friction coefficient than nylon and delrin.
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