SpudFiles

I want to make my piston valve serviceable by drilling 8 screws around the pilot area, I'm sure you all know what I'm talking about. If I can't cement the fittings how the hell do I make it a seal? What do I do?!?

O-ring.
There is no substitute..

You can spread room temperature vulcanization silicone sealant on the plug and in the socket, then glue it in. Wait 24 hours for it to cure, drill the holes for screws, and stick 'em in. If you need to take it apart, all you need to do is grab the plug in a vice and twist the T. It will break the silicone and you can pull it out.

I have had the same issue, try using silicone around the fitting because it should seal but you should be able to get it off if needed. (thats what happened for me, but could be different depending on the type of silicone)

Edit: noname beat me to it.

Brian the brain wrote:O-ring.
There is no substitute..

Just remember to measure more then once before you start cutting! Take your time, many of builders make easly avoidable mistakes by being in a hurry, myself included!

Although I've been working on it for ages, I'd recomend you use metal instead of PVC. I'm making a piston valve that's made mostly of galvanised steel, and the benefit to that is that you can service it very easily (just unscrew the pieces) and it's tough. Although a bit harder on the wallet, I think it's ovarall a bit more practical.

EDIT: I decided to use metal after I tried putting screws into the "T" twice (to make the piston servicable) and kept ruining the whole valve when I drilled the wrong types of holes.

How possible is it for self tapped screws only been screwed in/out once or twice to blow out when the chamber is pressurized above like 80 psi?

gwoloshyn wrote:How possible is it for self tapped screws only been screwed in/out once or twice to blow out when the chamber is pressurized above like 80 psi?

not very, a screw has about a 16th of an inch surface area in which the air can push on, thats like 5 pounds. but a tap is only $7.

Self tapping screws mite crack your tee. I've seen them tear sheet metal.

Whoops, i meant a machine screw that I tapped without using a tap

Guess my question is answered. thanks

I've never used a tap for screws, and nothing using them have blown apart. As long as the hole you drill isn't too small, and there isn't too much stress on the fitting, it should work fine.