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First Pneumatic

Posted: Sat Jun 03, 2006 6:02 pm
by frogy
My first pneumatic

This is the concept for the gun:
http://img157.imageshack.us/img157/8009 ... ept1vi.png

Full Shot:
<img src="http://img157.imageshack.us/img157/8031/fullshot1cj.jpg" alt="">

Full Shot w\ Ghetto Block:
<img src="http://img158.imageshack.us/img158/7084 ... ock3mc.jpg" alt="">

Valve and accessories:
<img src="http://img157.imageshack.us/img157/1236 ... ess0fa.jpg" alt="">

"Business end":
<img src="http://img157.imageshack.us/img157/2065 ... end2tk.jpg" alt="">

This was a fun cannon to build, and I'm sure it'll be fun to shoot now that it's finally done, I still have to make a wood block for the barrel to seat in, but that's like 1 minute of filing a 2x4 :D

Posted: Sat Jun 03, 2006 6:10 pm
by jrrdw
Did you or are you going to use the GGDT to find out how it's going to shoot?

Posted: Sat Jun 03, 2006 6:22 pm
by saladtossser
ggdt says 400 yards and possibly beyond

Posted: Sat Jun 03, 2006 6:51 pm
by CS
Should have bought from me...

Posted: Sat Jun 03, 2006 8:00 pm
by Atlantis
Would'nt it be more fun to see how it shoots when , I don't know...YOU SHOOT IT! GGDT kinda takes the fun out of it. Make sure you post pictures.

Posted: Sat Jun 03, 2006 8:48 pm
by frogy
400 yds isn't great... I shoot that with arrows out of my combustion,, whats wrong with my design?

Posted: Sat Jun 03, 2006 9:45 pm
by Benny
theres nothing wrong with your design.

Posted: Sun Jun 04, 2006 2:06 am
by )DEMON(
are you going to mod the sprinkler valve?

Posted: Sun Jun 04, 2006 6:04 am
by frogy
The sprinkler is modded in the pic, but I didn't draw the hose or the blowgun.... so yes I will be modding it


I had Home Depot cut the pipe into 6' and 4' sections so it would fit into my dad's truck.... For the 3'' Chamber should I use a 6' or 4' section? Nothing is in concrete yet (in this case.... not in PVC cement).

I'm not going to use the 1'' barrel for long, once I get my fittings it will be used to make PVC rockets \ a mini probably.... I already have 1½'', 2'', and 2½'' barrels for my ABS combustion that all go down to a 2'' Male

So I'm soon going to put on a 1'' to 2'' and a 2'' female so I can use all my other barrels....

I think a 6' Chamber sounds nice, I have a 300gallon Industrial Air Compressor, so I'm set :D

Posted: Sun Jun 04, 2006 2:45 pm
by CS
6' x 3" chamber, dont you think thats a bit much to put threw a sprinkler?

Posted: Mon Jun 12, 2006 9:45 am
by frogy
I have almost all the parts to make the gun now, I just got my 3" Coupling and 3" to 1" bushing in the mail, so now all I need is my valve, schrader, and gauge.... Which Joel said he's shipping today...

I plan on having the gun done by this weekend... hope so, I'll take pics and some damage pics...


How long should it take for my gun to fill my Chamber\Elbows, they're about 340 ci. and my Medium-Size Air Compressor does 3 CFM's at 90psi

3 CFM * 12 should mean it does 36 ci. per minute... 340 / 36 = 9.444444 which would mean 9.5 minutes!?!?!?


I have a giant air compressor that holds like 200 gallons at 200psi so I should have plenty from that, but how the heck can I use this thing anywhere else?

Even a big air compessor at like 6 SCFM would take about 5 mins to fill my gun to 90 psi on the calculations that I'm using...

Can someone help me out?

Edit:
I know that 1 Gallon = 231 ci. and I found an 8 gallon compressor that can fill to 100psi in 12.5 seconds and it's rated to 9 SCFM @ 100psi

8 gal * 231 = 1848 ci. in 12.5 seconds... going by my calculations
that's 147.84 ci. per second.... with what Hitachi says

but with my calculations...
9 SCFM * 12 = 108 SC-inches-M so I got 1.8 ci. second... what am I doing wrong?

Posted: Tue Jun 13, 2006 4:57 pm
by frogy
I found out what I was doing wrong... I was convertins 1 ft³ into 12 in³
when really 1 ft³ = 1728 in³

I really need help on what to make my 1" nipple that goes between the (2) 90's so my sprinkler valve clears the gun while I'm threading it on... My 90's are only 2.5" tall when sat on an open end

So thats 5" from the middlish part of my bushing

Here's a picture to explain it... Really all I need to know is how wide a 1" Orbit Watermaster is so when I thread it it can do full circles without hitting the 3" coupling

<a href="http://imageshack.us"><img src="http://img133.imageshack.us/img133/4237/question3qh.png" border="0" width="562" alt="Image Hosted by ImageShack.us"></a>

Edit: I found out that the sprinkler is 4-1/2" tall with the solenoid
Can someone tell me how tall the solenoid is? I estimate 2" or so, but I'd like an exact answer if possible.

Posted: Tue Jun 13, 2006 5:18 pm
by djt
just eyeball it. its better to make it up a little too far than not far enough. if you want it to be like exact then just measure everything out and mathematicaly figure it out.

Posted: Tue Jun 13, 2006 5:22 pm
by frogy
I don't have a sprinkler valve yet, so I can't do either of those...

I do think that I'm just going to base mine off of Drac's gun, I can kind of see distances seeing that he has the same design except my 3" pipe is longer...

Posted: Tue Jun 13, 2006 5:32 pm
by djt
ooooo i musta read wrong i thought you said you had it. dang you must be anxious having all those parts but the valves.