Just another copper gun

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
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MaxuS the 2nd
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Fri Mar 21, 2008 10:35 am

Wow, really good job on this gun, 265psig is awesome, I wish I had that kind of pressure. How high do you reckon the compressor can go?

The lead slugs are quite impressive.
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hyldgaard
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Fri Mar 21, 2008 10:41 am

MaxuS the 2nd wrote:Wow, really good job on this gun, 265psig is awesome, I wish I had that kind of pressure. How high do you reckon the compressor can go?

The lead slugs are quite impressive.
Im really not sure about how high the compressor can go, but i remember POLAND_SPUD saying 35atm(around the same as 35 bar) but he wasnt sure either if i remember correctly. I will probably get a 25 bar gauge and a steel chamber some time soon, so i can do a little high pressure testing.
The lead slugs is really nothing special, everybody with a drillpress, a bit of aluminium and the possibility to melt lead can make these :)
POLAND_SPUD wrote:lol fridge compressors rulezzzz Very Happy

hyldgaard the gun looks good but that ammo is awsome Shocked

don't worry you can up the pressure a lot I think you can easily get past 400 psi.... but I am affraid that the airhose you have (in the last pic) is the first thing that is likely to fail when you get past 350 - 400 psi... you might try to get the smallest diameter of air hose you can - they have higher pressure ratings
Yeah i would like to up the pressure, im just a bit concerned about the copper chamber and my poor soldering abilities ;) and my gauge only goes to 16bar, I think im allready pushing it by taking it to around 18 :)
And by the way, THANK YOU, for the wonderful idea of using a fridge compressor, you have really made my life a lot easier :D
The airhose im using is rated to 20bar, but inside there is 2 other kinds of airhose with smaller diameter, working like some kind of a reducer to make that thin copper tube fit inside. How have you connected your compressor? Im having a hard time seeing that on your photos :?
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POLAND_SPUD
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Fri Mar 21, 2008 10:50 am

yes fridge compresors are capable of 35 atm and even more.... but you really need to get stronger airhose and good clamps and you have to thighten them really strong... it isn't nice when airhose ruptures at 30 bar - really...

I used and airhose from a foot pump (becuase it has small ID) sleeved into a garden hose, which protects the airhose form being dammaged by clamps... I suggest you to to do the same - get as small airhose as you can get and sleeve it into something bigger because you really have to tighten clamps a lot
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Antonio
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Fri Mar 21, 2008 11:03 am

I went to the shop today to look for similar parts as this gun. I found out that i needed to spend around 20E just on copper tubing and fittings. Thats why I decided not to buy the stuff, as my priority is multiple shot guns. Nice work man I am jealous:)
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hyldgaard
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Fri Mar 21, 2008 11:05 am

POLAND_SPUD wrote:yes fridge compresors are capable of 35 atm and even more.... but you really need to get stronger airhose and good clamps and you have to thighten them really strong... it isn't nice when airhose ruptures at 30 bar - really...

I used and airhose from a foot pump (becuase it has small ID) sleeved into a garden hose, which protects the airhose form being dammaged by clamps... I suggest you to to do the same - get as small airhose as you can get and sleeve it into something bigger because you really have to tighten clamps a lot
Thanks, will do that :) believe me, im very much aware of not doing anything dangerous with this kind of pressure, i know its very dangerous if your not careful enough.
ant wrote:I went to the shop today to look for similar parts as this gun. I found out that i needed to spend around 20E just on copper tubing and fittings. Thats why I decided not to buy the stuff, as my priority is multiple shot guns. Nice work man I am jealous:)
Yeah, copper isnt exactly cheap, but where im from its somewhere near the only pressure rated pipe you can get, so ill just have to pay :(
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chartreusesnot
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Fri Mar 21, 2008 12:13 pm

Hows the flow on a fridge compressor?
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STHORNE
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Fri Mar 21, 2008 12:15 pm

chartreusesnot wrote:Hows the flow on a fridge compressor?
well worth the money
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hyldgaard
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Fri Mar 21, 2008 12:45 pm

sthorne wrote:
chartreusesnot wrote:Hows the flow on a fridge compressor?
well worth the money
Absolutely correct. it fills the chamber on this gun to 18 bar in 16-18 seconds.
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Antonio
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Fri Mar 21, 2008 1:26 pm

hyldgaard wrote:
sthorne wrote:
chartreusesnot wrote:Hows the flow on a fridge compressor?
well worth the money
Absolutely correct. it fills the chamber on this gun to 18 bar in 16-18 seconds.
I expected it to be slower, so its pretty impressive that pump. If it fills that fast parts probably heat up as well.
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hyldgaard
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Fri Mar 21, 2008 1:58 pm

ant wrote:
hyldgaard wrote:
sthorne wrote:
well worth the money
Absolutely correct. it fills the chamber on this gun to 18 bar in 16-18 seconds.
I expected it to be slower, so its pretty impressive that pump. If it fills that fast parts probably heat up as well.
Not really actually, but im pretty sure it has to do with me not shooting that much (5 shots per "session") and me being in a very cold shop when i use it.
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mark.f
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Fri Mar 21, 2008 2:03 pm

One day we need to turn an old 4-cyl engine into a glorified pump with four barrels. Drill and tap the intake out exhaust ports for pipe fittings, install some check valves and an intake filter, hook that baby's crankshaft up to a testbed V-8 and say hello to Supah-Flow!

Nice job on the cannon. I've only got one 300 psi shot under my belt, because pumping the cannon up to that much fried my pump, (Husky home-depot model).

EDIT: just remembered I filmed it too. This should give people an idea of what higher pressures can do for a relatively "low-power" cannon.

Linky

EDIT II: Here's your GGDT.

<div align="center">Image</div>
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Ragnarok
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Fri Mar 21, 2008 5:09 pm

hyldgaard wrote:Finally, yes, do go get yourself a fridge compressor, it makes life 45% better.
Excellent. I only needed one to make life 42.86% better, so that leaves me with a little spare just in case.
Does that thing kinda look like a big cat to you?
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POLAND_SPUD
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Fri Mar 21, 2008 5:45 pm

18bar in 16 - 18 seconds..... you are lucky... it has better flow than mine
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hyldgaard
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Sat Mar 22, 2008 2:28 pm

Thanks for the GGDT'ing markfh11q :) quite what i expected, but you never know.

Took a picture of my ammo i use for accuracy, its 11mm ball bearings encased in candlewax, weighing 6grams total. (these doesnt look too good, but it was the last few i had)
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I shot them at an old computer case, which is 1mm steel plate. Shot was fired from 15m.
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Also i made a dart for some penetration power experiments (not very hard to see im new in this area :lol: ) but for now im a bit worried about ricochets, any advice on protection against this? I know that it will tumble in flight, but thats just a matter of being close enough when firing it :tard:
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POLAND_SPUD
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Sat Mar 22, 2008 4:35 pm

lol I am going to say it again - you make awesome ammo... AFAIK you should avoid firing at right angles - but it also results in less penetration (or ricochets :shock: ) I always fire at things that are at least 10 m away - it might seem difficult but in fact it isn't and I try to avoid right angles - in this way even if something bounces of the target it doesn't come right at me
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