maintable seal for piston

[jitup]

Ok, This is truly the last question about my piston valve and it will be finished over the weekend.

I want to make the piston accessible if something goes wrong so I can fix it.
This is what I was thinking, correct me if I am wrong.

I was going to wrap a strip of rubber around the out side of the pipe (piece of new bike tube), nudge the end cap on, screw in about 10 screws half way, put a little silicon around the base of each screw, then tighten. If this is correct let me know. Are 10 screws enough or too many. Is the silicon needed?

Thank you.

[ALIHISGREAT]

i just put threaded fittings on the back of my pistons...

but just to make sure i understand... you mean like the screws in this pic?

[FishBoy]

let's say your psiton housing is 1", then put a 1" female adaptor behind the piston and then a 1" male with your pilot attached. If the piston breaks, unscrew the pilot and take out the piston.

[jitup]

correct. I would have put a threaded fitting, but than I could not use my pilot valve and the if I changed my design to allow me to use a threaded adapter, the pilot volume would be to large.




I want the screws to be done like the above pic. Am I going about it in the right way?

[ALIHISGREAT]

when i was contemplating a barrel sealing piston last year, my design was as shown below.


you make the piston to fit into whatever size of pipe the tee is so in this case it would have been a 28mm copper tee with some 28mm copper inside which has a 26mm ID so the piston would be 26mm pin diameter then you simply need a solvent weld to threaded coupling on the back.

now you may have to make a slightly longer piston, but it won't make any difference to performance and you could always attach something to the cap on the back to fill the space.

[jitup]

I am sorry for being unclear. I made a special 1.5 in diaphram valve as the pilot. it attaches directly to the back of the T. If I put a threaded adapter the pilot volume of the diaghram will be to large. I just need to know if my above description will work

I was going to wrap a strip of rubber around the out side of the pipe (piece of new bike tube), nudge the end cap on, screw in about 10 screws half way, put a little silicon around the base of each screw, then tighten. If this is correct let me know. Are 10 screws enough or too many. Is the silicon needed?

[ALIHISGREAT]

Sorry for the misunderstanding, i think that it should work, but there are probably better, neater ways of doing it.

i would put either an o-ring, or just a disc of rubber inside the cap to seal up against the tee and maybe o-rings could work for the screws too?

[jitup]

Thanks. I will wait till tomorrow before I put it together to see if I get any more suggestions.