help with my piston design please

[JDP12]

Hello all,

well I need some help with my piston design, just want to make sure that it is okay.

The 1.5" pipe leads to a 1.5" Male Adaptor, because I have multiple barrels, and they all have 1.5" female threads on them, so I don't want to have to make all new barrels.
I'll also be making a 3" t-shirt barrel
What do you think?? What, if anything lol, needs to be improved??

Okay I have a couple changes to make, but I didn't feel like redrawing it so here it is. Instead of the 2" plug...cuz I can't find one on mcmaster.com that isn't threaded..I'm going to use a short section of 2" pipe and then an end cap.. Also, the two wooden things will be the same size because they will both be going inside 2" pipe

I have a couple questions that I didn't write on the page however.

1) How many screws should I use to secure the 2" plug????

2) How can I secure the bumper so it stays in place while firing, but so I can take it out for maintenance???

3) How big should my equalization port be?? 1/32???

4) How can I make a check valve so that air can't escape through the equalization port when firing??

5) Okay people...I can't find a simple 1.5" male thread on mcmaster.com that is white PVC, and is a socket-weld besides the beige and green-can anybody help me out??

come on guys, 15 views, no help????
the white line that seeems to be cuttin the piston in half is white-out, ignore it

<img src="http://img2.freeimagehosting.net/uploads/f7a012b868.jpg">

[JDP12]

sorry for double posting..I can't edit right now for some reason..my computer is being stupid.


I forgot to add that it is being vented by a 3/4" sprinkler valve..

COme on, please..I'd like some input on this.

[super spuder]

it should work, it has been done many times before, just do it right and it will work just fine i don't know if that bumper will be good enough, but you might want to have something a little bit better for a bumper.
edit: haha i just noticed you had questions
1) How many screws should I use to secure the 2" plug????
um, i don't think you should need any if you do a good job glueing, if you do want to put screws in it i would say 3, haha i am soo stupid, if you are not going to glue it, use 5, and make sure you use thread sealer on them
2) How can I secure the bumper so it stays in place while firing, but so I can take it out for maintenance???
you could glue the bumper to the end cap or the piston, but as i said earlier, you might want to rethink your bumper idea, but i don't know for sure, it might work just fine.
4) How can I make a check valve so that air can't escape through the equalization port when firing??
use a presta valve, they are sometimes on bike tires, not to be confused with schrader valves, they will not work

[meatballs]

1) no idea, no experience here

2) one thing you can do is cast a bumper out of hot glue. take an inch or so of 2 inch pipe and a similar length of 1 inch pipe (or 1 1/4 inch, not sure if 1 1/2 would be thick enough), center the 1 inch pipe in the 2 inch pipe. then pour hot glue into the gap between them til its ~1/2 inch thick, when it cools it makes a perfect bumper. it will fit snugly in place in the two inch pipe, so it will stay in place by itself while being removable. or use an adhesive that can be removed without hurting the pvc, by solvent or something.

3) 1/32 would be fine, presta would work better since its one way. or you might not need a hole unless you have an absolutely perfect seal around the piston which is hard to get.