Posted: 01/17/2010 17:56 PM Post subject: Mini Coaxial Piston.
Major General
Joined: 21 Jul 2009 Posts: 1486 1475.73 Spud Bux
Im building a mini coaxial gun from 1/2 in copper. The barrels a piece of brake line. All I have left to do is epoxy it together and add the piston. My question is whats the best was to build the piston. Ive considered using epoxy or bondo but wasnt sure about the air leaking around the epoxy piston. Do i need to cut a groove in it, and what size if so. Also is there a way to make it serviceable without using fittings,would using screws work.
Posted: 01/17/2010 21:06 PM Post subject: Re: Mini Coaxial Piston.
aspiring machinist
Joined: 15 Mar 2007 Posts: 18051 32498.46 Spud Bux
clemsonguy1125 wrote:
I've considered using epoxy or bondo but wasn't sure about the air leaking around the epoxy piston. Do I need to cut a groove in it, and what size if so.
Works perfectly well for me, I've never needed to make an equalisation hole or groove because unless you put in an o-ring, the piston will never be 100% airtight.
Quote:
Also is there a way to make it serviceable without using fittings, would using screws work
You could conceivable cast an epoxy plug with an o-ring for airtightness that is held in with screws.
For convenience I would use hotglue for the piston its relatively light and not brittle at all and to attach a sealing face you just have to heat up and press the sealing face down...
Why not just get some 1/2" fittings, I think you're gonna have a hard time using screws as it will be hard to get a 100% seal unless you tap the screws in with the corresponding tap.... to much work IMO?
Well last night will looking for some hot glue sticks I found a marker cap thats slides easily and while looking through the chamber with a piston in it you cant see lite so I ll use that
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