Page 1 of 1

Alternate 3" pistion valve design

Posted: Tue May 29, 2012 1:32 am
by samiam0295
Hi, I'm new to the forum, but I have made a few spud guns before. Most of the valves designs I see on this site and others use a sleeve inside of a PVC tee. I thought up this design and will be building and testing in the next week. My design bores out the "Lip" inside of the PVC tee so that a 3" piston can be used that freely slides within the tee. Any input would be appreciated. Thanks.

Posted: Tue May 29, 2012 2:00 am
by jackssmirkingrevenge
Welcome to the forum :)

Here's how I would make it, a lighter piston opens quicker, puts less stress on the bumper and you gain some barrel length too. Of course it would depend on your barrel diameter because you might cause a flow restriction if the barrel is too wide.

Posted: Tue May 29, 2012 5:04 am
by MrCrowley
I imagine the lip has some structural function, removing it might not be a good idea.

Posted: Tue May 29, 2012 6:45 am
by mattyzip77
Its done like this in a supah valve so I dont see why not, also I know alot of people who have done this with a two inch tee..

Posted: Tue May 29, 2012 6:56 am
by MrCrowley
True, I've done it myself with a hole saw but I couldn't bring myself to use it as I'm scared of large diameter PVC enough as it is. The lip probably does only act as a stopper for pipe that is socketed in the tee but I assume they take it all (the presence of pipe in the tee sockets) in to account when they rate them.

Posted: Tue May 29, 2012 9:39 am
by samiam0295
jackssmirkingrevenge wrote:Welcome to the forum :)

Here's how I would make it, a lighter piston opens quicker, puts less stress on the bumper and you gain some barrel length too. Of course it would depend on your barrel diameter because you might cause a flow restriction if the barrel is too wide.
The outlet pipe is 2" running right to a threaded adapter for the barrel, so 1/2 should be enough space around the barrel. I like your lighter piston design, as the acrylic is heavy. It is actually scraps of solid surface countertop (Corian). It smells very bad when drilling or sanding it. Unfortunately I will not have access to the drill press or lathe until friday :cry: , but I'll see what I can do until then!

Posted: Tue May 29, 2012 9:59 am
by jackssmirkingrevenge
Silly question, if you have access to a lathe why not machine a one-piece piston out of acetal or UHMWPE?

Posted: Tue May 29, 2012 10:20 am
by samiam0295
At this stage I am still prototyping, I will possible machine a one piece piston eventually. However, I have the acrylic and the pvc, and the pvc will fit so perfectly in the tee, it isnt worth the cost and effort to machine the piston at this point.

Posted: Tue May 29, 2012 10:51 am
by jackssmirkingrevenge
samiam0295 wrote:it isnt worth the cost and effort to machine the piston at this point.
If you're asking someone else to do it I can see your point, but if you're doing it yourself a decent cup shaped acetal piston shouldn't make more than a few minutes to turn.

Posted: Tue May 29, 2012 11:16 am
by samiam0295
until I have a final design, I see no reason to buy acetal stock to make a custom piston when I can do essentially the same thing with things I already have laying around. However, the final version would definitely benefit from a one piece machined piston.