Silicone Sealing Faces

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noname
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Sun Mar 11, 2007 8:45 pm

This is for people who have pistons that aren't completely sealing.

What would people think of molded silicone sealing faces for piston valves? I don't think its been done before, and silicone, when put pressure upon, flexes and stretches and would seal itself into any tiny inperfections in the seat of the valve, making it seal completely. I have a piston that isn't sealing 100% (leaks about 30 psi per minute), and I have a silicone sealing face in a mold as I'm typing this.
Tell me what you think.
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spudthug
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Sun Mar 11, 2007 8:51 pm

should work noname and i havent ever seen it done before...are u going to put it on an old gun or make a new one??id like to see it toigether with the peice if i get a piston valve i might have to do it.....btw check out my first pneumatic :D


EDIT: just posted it
Last edited by spudthug on Sun Mar 11, 2007 9:13 pm, edited 1 time in total.
4" piston valved cannon-half done..( i spilt my cement...)

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Atlantis
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Sun Mar 11, 2007 9:10 pm

I had a similar idea a while back though I never tested it. I actually made a piston out of silicone and a grocery bag, and a golf ball for weight and filling. I lined the inside of the pipe with a plastic bag and filled it with silicone, and stuck a golf ball in it to fill in the rest.
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frankrede
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Sun Mar 11, 2007 9:39 pm

I tryed to make one in a 2" coupling using silicone out of a caulk tube but It never dryed completely after atleast 3 weeks/wth?lol
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noname
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Sun Mar 11, 2007 10:18 pm

How thick was it? The whole coupler? I'm just making discs, to bolt or glue onto the front of the piston to make it seal.
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chaos
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Sun Mar 11, 2007 10:26 pm

i got some silicone sheets at work ill get my dad to pick them up during the week. i cant believe i didn't think of this.
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frankrede
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Sun Mar 11, 2007 10:33 pm

noname wrote:How thick was it? The whole coupler? I'm just making discs, to bolt or glue onto the front of the piston to make it seal.
3/8"
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Matheusilla
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Mon Mar 12, 2007 12:48 am

I wouldn't think that silicone would be strong enough to resist tearing and such.

I have an idea if someone would like to try it. Instead of a flat sealing face why not a round one? Like a rubber ball? And what if the rubber ball was connected to the piston with a short length of some heavy coil spring? I'm thinking that it would act like a diaphragm crossed with a piston.
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A-98
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Mon Mar 12, 2007 12:50 am

hot damn boy. that was a good idea. i think ive seen it posted before tho :?

however, im not sure what you mean by the spring part, could you explain.
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Matheusilla
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Mon Mar 12, 2007 1:37 am

The spring would connect the ball to the face of the piston and allow it to center itself in the end of the barrel/valve seat. If it is a big enough piston, the spring could be a coil over shock spring from a motorbike suspension, or at least something tense enough to be able to pull the ball away from the valve seat without stretching too much. The spring doesn't have to be very long, it's just to allow for some movement so that the ball seats well. It may have been done before but it is a completely fresh idea for me.
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Hotwired
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Mon Mar 12, 2007 11:20 am

Silicone would seal but it would also deform quite a bit under pressure in an undesireable way and with metal barrels it could get cut through.
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noname
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Mon Mar 12, 2007 5:31 pm

Well, it's in the mold, I'll test it in a day (if it's dry).
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chaos
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Wed Mar 14, 2007 4:14 am

well.........did it work?
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noname
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Wed Mar 14, 2007 7:22 pm

Patience is a virtue. :D
I popped it out of the mold this morning, it was 100% dry. I'll test it and post results when I finish my homework.
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chaos
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Thu Mar 15, 2007 5:10 am

$10 it will tear.........not really i don't bet money, but i think it will tear.
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