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Posted: Sat Apr 24, 2010 3:02 pm
by jackssmirkingrevenge
Lovely! Especially towards the end. You know, you're a timer circuit away from having a golf ball autocannon... not to put any ideas into your head or anything

Posted: Sat Apr 24, 2010 3:15 pm
by c11man
You know, you're a timer circuit away from having a golf ball autocannon... not to put any ideas into your head or anything
do you really think this hasnt crossed my mind? i am looking into it and if i do make a circut i will add things such as a digital pressure sensor that i have laying around( i have lots of goodies laying around dont it?) so that it wont attempt to fire if the chamber is under 50psi so that the valves properly accuate
Posted: Sat Apr 24, 2010 4:02 pm
by Mr.Sandman
c11man wrote:You know, you're a timer circuit away from having a golf ball autocannon... not to put any ideas into your head or anything
do you really think this hasnt crossed my mind? i am looking into it and if i do make a circut i will add things such as a digital pressure sensor that i have laying around( i have lots of goodies laying around dont it?) so that it wont attempt to fire if the chamber is under 50psi so that the valves properly accuate
Am I sensing a tone of hostility? Hehe. Looks good c11 The valves add a nice touch.
Posted: Sat Apr 24, 2010 6:05 pm
by deathbyDWV
Looks really good. I must have missed this when you first posted it... Maybe drilling a hole in the back of the bolt is all I needed to do to make mine work...
Video is good too...
Posted: Sun Apr 25, 2010 4:31 am
by jackssmirkingrevenge
c11man wrote:do you really think this hasnt crossed my mind? i am looking into it and if i do make a circut i will add things such as a digital pressure sensor that i have laying around( i have lots of goodies laying around dont it?) so that it wont attempt to fire if the chamber is under 50psi so that the valves properly accuate
Looking forward to it

You might consider adding a bypass with a check valve to fill the chamber quicker.
Posted: Sun Apr 25, 2010 3:36 pm
by c11man
i am planning on reduing the piston with some highflow check valves built in for faster filling, a bypass is also a good idea but if the cracking pressure is too low the piston might have trouble seating
with the parts i have ordered i will be able to adjust the ROF from 25rpm al the way up to 70rpm. even with the new piston and a good compressor i dont see this cannon being able to handle over the 70rpm so i think i am good
Posted: Sun Apr 25, 2010 10:34 pm
by c11man
due to the repeated slaming forward of the piston against the porting pipe it developed a crack and the pressure blew a chunk of that pipe out. of course the piston has a bit of trouble sealing on a pipe thats not all there.
so in other words this cannon is currently DEAD/BROKEN!
it will be fixed but that will take some time due to the fact that the entire valve section will need to be replaced since it is all glued together
suggestions for improvements/upgrades that i can do while fixing it?
Posted: Sun Apr 25, 2010 11:07 pm
by Mr.Sandman
c11man wrote:due to the repeated slaming forward of the piston against the porting pipe it developed a crack and the pressure blew a chunk of that pipe out. of course the piston has a bit of trouble sealing on a pipe thats not all there.
so in other words this cannon is currently DEAD/BROKEN!
it will be fixed but that will take some time due to the fact that the entire valve section will need to be replaced since it is all glued together
suggestions for improvements/upgrades that i can do while fixing it?
I had a very strong feeling this was going to happen. A new part if you rebuild it should be a bumper. You have a knack for breaking pvc pipe with your creations eh?
Posted: Sun Apr 25, 2010 11:15 pm
by c11man
there is a bumper behind the piston but thats not what broke, after firing the piston is back, valve is opened and the piston slams forward. this repetative slamming caused the smaller 1 1/2in pipe to break.
and i dont have a knack for it, they are just accidents. only twice has my pcv broke and once was dwv
Posted: Sun Apr 25, 2010 11:29 pm
by Mr.Sandman
c11man wrote:there is a bumper behind the piston but thats not what broke, after firing the piston is back, valve is opened and the piston slams forward. this repetative slamming caused the smaller 1 1/2in pipe to break.
and i dont have a knack for it, they are just accidents. only twice has my pcv broke and once was dwv
Sigh I can never have a joke can I

No what I meant was a bumper on the bolt or maybe a stronger barrel and bolt made of metal. Pvc doesn't like being subjected to high impact for some reason.
Posted: Mon Apr 26, 2010 4:01 pm
by Gun Freak
Oh dang that sucks, I know what its like to rebuild whole glued sections

Posted: Mon Apr 26, 2010 7:11 pm
by Gaderelguitarist
Perhaps you could use a softer type of rubber for the sealing face of the piston. That might work.
Posted: Mon Apr 26, 2010 8:50 pm
by 30cal man
here is a quick drawing i drew up for a very simple full auto circut it works i tried it when i used something simular to make a c cell batterie launcher however i lost interest when i ran out of c batteries which was very quick let me know what you think
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Posted: Mon Apr 26, 2010 9:08 pm
by POLAND_SPUD
not a bad idea but it will be easier to use a timer relay
Posted: Mon Apr 26, 2010 9:45 pm
by c11man
yeah im not gonna mess with screws and contacts on the bolt. but a very creative idea!
what i am going to do is place a spring behind the piston so that it is against the barrel before pressurization elimitateing the forward slam of the piston. also i will put a bypass hose from the pilot area to the chamber that will hasten filling and a check valve will prevent back flow.
so i gotta order some parts, go to the store and it should all be up and running in about 3 weeks