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Posted: Sun Apr 26, 2009 10:57 am
by CpTn_lAw
yeah well, i might be forced to see the design again, the cannon is now at it's 4th revision in 2 weeks, more power, quicker activation, but also less power...I'll go in the week to search for some mecanical solid grease lol XD
By the way, i think the liquid weapon-oil i'm using is eating the hot-glue piston and that why it's more sticky than slipery...might be a problem...

Posted: Sun Apr 26, 2009 11:39 am
by Technician1002
CpTn_lAw wrote:yeah well, i might be forced to see the design again, the cannon is now at it's 4th revision in 2 weeks, more power, quicker activation, but also less power...I'll go in the week to search for some mecanical solid grease lol XD
By the way, i think the liquid weapon-oil i'm using is eating the hot-glue piston and that why it's more sticky than slipery...might be a problem...

Weapon oil has solvents in it to remove deposits. Not the best stuff to use on plastic.

Lubricants compatible with your materials is a must. For plastic, I've seen everything used from dish soap and water to condom lube. If it won't break down a condom, it's probably not going to hurt the plastic piston.
Posted: Sun Apr 26, 2009 12:56 pm
by SEAKING9006
I know I haven't been active in forever, but I haven't been idle. I have a prototype bolt action rifle in the garage that I worked on a few weeks ago, however since I didn't have GGDT handy, I got the tank size WAAAAY off. Need to build a second one, this time with a different valve and less of a bend.
By the way, there's a diamond disk for dremels that works BEAUTIFULLY on PVC pipe. Cut out the bolt slot and the breech with it, works great. But, I won't work on it for a while, I've been in trouble with the school now and I have lost quite a few privileges. I just now cranked out some DarwinBots 2 code that I'd been sitting on for a month waiting for a chance to finish. I'm not quite in the mood for building anything.
But if anyone wants to know, there's a bolt action rifle and a large air tank in the garage waiting for a reason to be used. The air tank is two 3" two-footers with a whole reg/ballvalve setup for use on a backpack. Works nice as a compressor extension.
Posted: Sun Apr 26, 2009 8:03 pm
by jonnyboy
Well this is in general spud discussion but it seems like an ok spot to post this.
I'm working on a motorized bike
following the directions here.I got a bike from a garage sale this weekend and am picking up the leaf blower tomorrow. Then to home depot for mounting supplies.
I think this will be the first time since I've picked up spud gunning that I will be going to home depot for something other than pvc!
I'll be sure to edit this post with pictures when its done and maybe a video.
Posted: Sun Apr 26, 2009 8:39 pm
by MountainousDew
Hey JonnyBoy,
Actually instead of using a leafblower, you should use a chainsaw...
Me and my cousin (My cousin and I) build one a coulpe years back with a 9hp chainsaw we bought at a yard sale for ten dollars. You might not find one that cheap but the performance was much greater than if we would have used a leaf blower.
Edit: Just reread your post, I guess you already started... So maybe for a future project.
Posted: Mon Apr 27, 2009 6:40 am
by inonickname
Just broke my new aluminum piston out of the mold (cast it in the fire, so there may be tiny bits of carbon in it, but it looked pure while casting and I can't see anything).
Used to be a Mercedes (gearbox)..
Just gotta find a way to stick my sealing face to it and we're movin.
Posted: Mon Apr 27, 2009 7:37 am
by CpTn_lAw
hey coooooool piston!! I wish i could do one like yours

Mine is shitty ^^.
New vids btw, 600 frames/s paintball at 20 meters, and 1200 frames/s footage of a .9gram steel BB piercing through a full deo can.
Posted: Mon Apr 27, 2009 8:27 am
by inonickname
You could, trust me. You don't even need a proper furnace or crucible.
How I did mine was get some chunks of aluminum (which had been melted down previously and reset. Then put them on top of a VERY HOT fire (around 700 Celsius plus) and put some chunks of wood on top so they begin to burn and you don't lose too much heat. Not this depends on what kind of fire you have, but ours is on stilts so it works like a furnace and ash falls through to the bottom.
Eventually liquid aluminum begins to drip from somewhere into the ash so it is then caught in a tin (steel) can with some metal bar bolted to it until there is enough (keep it warm in coals). All of the impurities should float to the top, just tip it into your mold being careful you don't tip any slag in.
For larger scale/repeated things you'd want a purpose built furnace, but this would work fine.
(Btw, just sanded it up and epoxied the bolt in to attach sealing face)
Posted: Mon Apr 27, 2009 11:41 am
by CpTn_lAw
thanks for the explanation! Very clear and all! As for the piston gun, i'll be posting it in the evening (in france => in a few hours)
Posted: Mon Apr 27, 2009 12:09 pm
by Carlman
All metal >300psi Sawn off marble caliber shotty

Posted: Mon Apr 27, 2009 12:47 pm
by VH_man
Bolt Action .40 Cal hammer Valve Rifle. For real this time

Posted: Mon Apr 27, 2009 1:25 pm
by covey12
i am fixing my piston cannon, making various fireworks using only fuses, so the dont explode making them legal where i live, even though i can just cross county line and by illegal fireworks lol, and experimenting with combustions, not that any of you care lol
Posted: Mon Apr 27, 2009 9:59 pm
by inonickname
Well I fined my piston up some:

Apart

Assembled

Fit is uncanny.
There is a bolt (minus head) epoxied into the piston. Can I secure my sealing face with a nut/washer or do I need epoxy or something to seal it? should do that itself eh?
Posted: Mon Apr 27, 2009 11:05 pm
by Technician1002
covey12 wrote:i am fixing my piston cannon, making various fireworks using only fuses, so the dont explode making them legal where i live, even though i can just cross county line and by illegal fireworks lol, and experimenting with combustions, not that any of you care lol
Umm..

Talking about fireworks and a launcher here is a good way to get a thread locked and yourself banned.

Please don't do it again. The moderators have no sense of humor in that regard.
Posted: Tue Apr 28, 2009 3:31 am
by SubsonicSpud
I'm working on a completely transparent full auto QEV & popoff gun for 1/4" ammo. To be mounted on a radio controlled turret with my special remote ammo feed system (fingers crossed)
SubsonicSpud