SpudFiles

I got bored earlier this week and decided to try making a pneumatic. I decided to just go with a basic 1 1/2" T piston valve design (2" T with a 1 1/2" sealing face). This is the first pneumatic that i have made, and i'm fairly suprised by its performance thus far. I have been firing it at 130 psi, and so far have been getting at least 300 yards, maybe even close to 400 (my backyard extends 200 yards, and the golf balls are well above the 70 ft trees at the end of it). I haven't done much damage yet (i'll get it out tomorrow and shoot some targets, posting damage pics), but it easily blew through a solid piece of 3/4" plywood.
Specs
2" piston valve
3" x 36" chamber
2" x 60" barrel (i know the CB ratios is off, i plan on making a new barrel eventually)
3/4" ball valve for pilot (i am currently waiting for a sprinkler valve to pilot)

I still have to make a barrel support, get the sprinkler valve, and paint.











i threw this in as a way to bring up suggestions to get to 200 psi (my compressor, though big, only gets to 150 psi)


EDIT:
Got it out yesterday and did some damage, though mostly spuds, so i didn't end up completely tearing my targets to shreds. I decided to go with a sanding drum as a piston, it works great, but it seems to have cut down on efficiency to some extent, though its much more reliable and seals every time...

This is the only video i have, sorry for the poor quality... This is a shot to a piece of 3/16 stainless steel sheet with a wood plug.



The hole in the middle is the damage from the shot (the plug then continued to tear the second layer from the first, of this scrap piece of industrial appliance), the face of it is caved in from a few potatoes.



dents to a stop sign that we have... it was in our yard when we moved in



potato hitting a piece of 1/2 in plywood



I don't remember what holes belong to what ammunition and what guns... (3/4 in plywood)

Nice, shame about the organic piston. Have you thought about using a bolt and washers?

the piston works great... most of the time. I do have a small lag bolt with a washer holding the sealing face on. The piston will work for now (i'll figure something else out after the fourth), but it certainly has issues with the singular, uneven o ring groove. I plan on having one turned eventually (so if anyone has an extra 2" delrin piston laying around that they don't want anymore...)

You can make a piston with o rings using a 1 1/4 inch coupling and 1 1/4 pipe. put the o ring on the pipe and sandwich it with the coupler. Also a 2 inch sanding drum works awesome as a piston. Just add a washer, bolt and sealing face.

is that bell reducer, pressure rated?

jsefcik wrote:is that bell reducer, pressure rated?

Theres no such thing as a pressure rated bell redoucher¡¡

mattyzip77 wrote:

jsefcik wrote:is that bell reducer, pressure rated?

Theres no such thing as a pressure rated bell redoucher¡¡

they have them by me, pena plas where i get my fittings from has them,


but dude if i were you i would put a pressure rating fiting there instead of that reducer!

No they dont stop lying they dont make them....

the fitting is pressue rated, i can get a pic of it if you guys really want, i've seen other pneumatics with bell reducers and they didn't have issues either.

Spears part number 429-420 is pressure rated. 4 inch to 2 inch bell reducer.
There was a web site that showed the Spears 429-420 as pressure rated.
I have seen bell reducers that are pressure rated and I am sure that Spears is the only one that makes them.

I will research to verify.

FLONE wrote:
Yeah, the pics don't tell the whole story. The 3 that I have all say 429-420, NSF pw PVC1, SCH 40 D2466. Spears manufacture. These are 4" to 2" bell style with a much gentler taper than the DWV reducers from Lowes. The socket depth is 1.380" using my Lyman dial caliper.
See attached link:

http://www.spudfiles.com/forums/bell-re ... 16512.html

Here is a suppler;
http://flexpvc.com/cart/agora.cgi?cart_ ... s-Reducing

just trying to be safe dude thats the last thing you need is a piece of pvc hitting you

I was only bustin jsekciks chops, however, judging by the socket depth of yours it clearly is not. I would use one, I have in the past, and I never had a problem. You also have another piece, the 2 inch female adapter glued to the other side of the reducer so I wouldnt worry about it. Others may feel differently, but as long as you solvent welded properly I wouldnt worry.

if i end up making a big (thinking of making a massive 4 in chamber) i'll consider a bushing reducer. i blew out a seal today, so i have to get a thicker piece of rubber, and i might put a washer behind it to prevent further blowouts... so damage might take a while

i plan on getting the barrel support completed tomarrow, and mounted, but i ran into an issue than i'm not sure how to fix... if i try to load a perfectly air tight projectile (as a potato), it pressurizes the chamber instead of letting air out the pilot. I have the sprinkler valve on now, but even with the ball valve on (and opened) it would send my push stick flying out the barrel... the problem is the piston's seal... but it leaks fine into the chamber, just not back out to the pilot. Any suggestions (not taking the barrel off, as it will be fixed), i was thinking of threading a ball valve into the base of the barrel.

The delay between pilot actuation and firing in the video suggests the piston is not performing at its best, yet there's no denying you're getting some pretty good performance out of it, good job