Sealing face

qwerty · Mon Sep 14, 2009 9:08 am

On my upgraded version of my bb coaxail (which now fires pellets)the rubber sealing face keeps coming of.
Its made of innertube and i epoxy it on (but i sand the piston first)after every 5 or so shots it just comes of after i fire it.
i was thinking of having thicker rubber maybe?

Does anyone know how to solve this problem?

MRR · Mon Sep 14, 2009 11:54 am

Innertube is pretty thin for a sealing face and it doesn't adheres with epoxy.

A solution would be to use a thicker piece of rubber. I tried innertube aswell and had the same problem. My solution was to wrap it around a washer and screw it onto the piston.

john bunsenburner · Mon Sep 14, 2009 12:23 pm

Rubber sheets in various thicknesses can be broughts in hard ware stores. Also, one can always have a washer smaller than the inside diameter of the barrel, with a nut smaller than the inside diameter of the barrel in front of the sealing face, so that only a small amount of rubber is exposes, and the rest is held firmly together by a bolt. Really, personally I would not recommend glueing as it is hard to remove, change rubber, and *usually* is inferior to solutions involving bolts and washers.

hoarp001 · Mon Sep 14, 2009 12:25 pm

On my big cannon, I found that superglue and epoxy didn't really work. My sealing face is made of 5mm thick hard black rubber, originaly used to push poo out from drain pipes.

I scored the surface of the piston face and the rubber first.

I used an adhesive called 'Sticks like sh*t'. It is a real glue, for trade use only, available in the UK. Its white, not a solvent or two part mix, and it comes in a caulking gun tube.

First I bent the seal back so all the score marks opened up, then spread the glue over it so all the glue went down into the cracks, then I stuck it on the seal, applied lots of weight and let it dry, then cur the excess off and sanded round to make it smooth.

Works perfectly, i just fired it for the first time in about a year, and the seal is still stuck on perfectly.

qwerty · Mon Sep 14, 2009 2:08 pm

'Sticks like sh*t'

sounds strong and...sloppy?

i think ill try it using a different glue maybe rubber solvent or something like that.
I cant really use washers because the barrel is 4.5mm and ive got a holle throung the middle of the piston and all the screws that ive tried are to small.

originaly used to push poo out from drain pipes.

I hope you washed it!

john bunsenburner · Mon Sep 14, 2009 2:10 pm

You could sand it down a bit...

qwerty · Mon Sep 14, 2009 2:14 pm

I Tried but the rubber dosen't sand its because its to soft and the grains just push into it

john bunsenburner · Mon Sep 14, 2009 2:15 pm

No the bolt, nut and washer

Gippeto · Mon Sep 14, 2009 10:39 pm

I used contact cement to attach the sealing face on the first piston valve I made, it's still going strong.

Don't waste your time with the water based crap, get the nasty, toxic, solvent based stuff.

Use it outside, and don't smoke around it. (Unless perchance the idea of undergoing skin grafting appeals to you.)

qwerty · Tue Sep 15, 2009 2:50 am

Ok.. like something that says this on the bottle "super strong super toxic rubber and plastic melting solvent" and in the back. "if swallowed get someone to call the funeral director and show them this label"

i-will · Tue Sep 15, 2009 2:55 am

i used the rubber cement that came with my inner tube patch kit. works great and you (or someone you know) probably already have it.

qwerty · Tue Sep 15, 2009 3:01 am

yeah i have an inner repair kit ill try that next time it comes of because it working at the moment.

Sealing face

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