Hand Pumpability.. And First post :)

Building or modifying BB, Airsoft, and Pellet type of guns. Show off your custom designs, find tips and other discussion. Target practice only!
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lozz08
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Wed Nov 24, 2010 8:33 am

25mm PN18 PVC pipe and endcaps, pvc cement and primer. PN18 is over 250 PSI working pressure. But you need to attach a shrader valve and a quarter inch fitting. (Read:epoxy)
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more_eggs
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Wed Nov 24, 2010 8:38 am

Well thats pretty much the exact chamber which is drying on my desk haha.. minus the high pressure rated middle section..
And I attached the end caps using epoxy..
Shrader valve is in the 3 way which connects the blowgun to the chamber and the pump, 1/4 inch fitting is on one end and pressure gauge on the other end of the chamber..

might sit it behind a door once its made and see how high it can go... but it should hold 200 i hope :)

though when I said a strong chamber I was talking more in the 500psi range
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jackssmirkingrevenge
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Wed Nov 24, 2010 8:57 am

more_eggs wrote:What are your tips on making a damn strong chamber?
In general for >300 psi applications, thick walled metal tubing, properly cleaned and roughened for adhesion, with suitable marine epoxy plugs.

I stress it must be thick walled, especially if the metal is something like copper or aluminium, because pressure can cause it to expand enough to leak or, at worst (as happened here and here with thin walled aluminium) cause the plugs to pop out, even if the epoxy itself does not shatter.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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more_eggs
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Wed Nov 24, 2010 9:08 am

Yeah thats some crazy stuff.. Well for now ill stick to <200psi and see how it all goes..
Further down the track if I steer towards a fridge compressor of something like it, ill stay away from thin walled aluminium
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Zeus
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Wed Nov 24, 2010 10:24 pm

jackssmirkingrevenge wrote:
more_eggs wrote:What are your tips on making a damn strong chamber?
In general for >300 psi applications, thick walled metal tubing, properly cleaned and roughened for adhesion, with suitable marine epoxy plugs.
How about some nice strong fittings designed for it?

(Zeus kicks JSR in the rear end with remarkable force, yet not enough or too little force to allow a painful JSR pun)

If you go down the epoxy route, drill a hole through the pipe, then pass strong cord or wire through it, if it leaks it won't become a secondary projectile.

I'd strongly recommend proper fittings, an end cap is less than $2 AUD.

Certainly cheaper than an extended hospital stay.

Epoxy can also be somewhat brittle, steel however isn't that brittle under these circumstances.

Good to see another Australian here, we're taking over.

I look forwards to seeing your results.
/sarcasm, /hyperbole
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more_eggs
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Wed Nov 24, 2010 10:32 pm

Yeah I hadnt planned on making the end caps from epoxy, just gluing the proper end caps on using it :D
Wishing the sun would come out so my stuff would set a bit quicker..
Where does everyone get their air fitting and such? Like I said earlier I was looking for a 3 way adapter, but bunnings was no help..
I was thinking like a specialist hoses and fitting store, but it might get a little expensive
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Crna Legija
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Wed Nov 24, 2010 10:47 pm

You should have got proper pvc glue and primer because it takes just as long to set and would be stronger

They have a few air fittings in the tool shop part of bunnings right next to nailguns and compressors
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Zeus
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Wed Nov 24, 2010 10:48 pm

You're in Brisbane if I remember right, Bellpro is up there but it isn't cheap, I go to Midland Irrigation for galvanised fittings, and a local hardware store for brass, Home hardware should have all you need though.

Bunnings is ok, Thrifty Link is good in some places, don't know what else you have up there, I'm in Victoria so I don't know the area.
/sarcasm, /hyperbole
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more_eggs
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Wed Nov 24, 2010 11:00 pm

They have a few air fittings in the tool shop part of bunnings right next to nailguns and compressors
Yeah thats where I got what I did get.. Though no nice Tee fittings :( ebay has some pretty nice ones for nitrous fittings in cars, annodized and all that... but they go for about $16 each..
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Patto
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Wed Nov 24, 2010 11:52 pm

In brissy there’s ( on the west side ) Mobile hose fixers, pirtek ( Expensive), Industrial fitting supplies - The best and cheapest !! bunnings and the hardware shops are really going to sting you for air fittings, even a trade tools of truck supply shop like Qld diesel spares would be better :wink:
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more_eggs
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Thu Nov 25, 2010 12:00 am

Thanks Patto..
Yeah ill have a look at somewhere like that next week, though I rekon my home made T fitting will suffice for now..
Anyone rekon I could find one of those crappy little toy guns that shoot bb pellets in chinatown haha.. U know the ones that you find at shows usually, they are really weak and shoot maybe 3 meter, but they come with like 50 BBs..just need some bb's to get me by for a little while and to get the popoff setup properly
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jackssmirkingrevenge
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Thu Nov 25, 2010 12:53 am

more_eggs wrote:Though I really like the breech with moving bolt.. seems so much cooler
I was staring atthis QEV animation and it got me wondering, is the fascination with reciprocal motion a guy thing? In the same way the male gender seems to be obsessed with penetration, putting things in goals and holes, hmmm...

I digress, back on topic.
one of those crappy little toy guns that shoot bb pellets in chinatown haha.. U know the ones that you find at shows usually, they are really weak and shoot maybe 3 meter, but they come with like 50 BBs
Note of caution, if the BBs are poorly made (not exactly round, visible mould lines) at best they will stick in the breech without sealing, at worst they might tear the seal.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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more_eggs
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Thu Nov 25, 2010 3:49 am

I was staring at this QEV animation and it got me wondering, is the fascination with reciprocal motion a guy thing? In the same way the male gender seems to be obsessed with penetration, putting things in goals and holes, hmmm...
Hahahaha no doubt about it..
Note of caution, if the BBs are poorly made (not exactly round, visible mould lines) at best they will stick in the breech without sealing, at worst they might tear the seal.
This is true.. Ill grab some metal bb's tomorrow, but I imagine the pop off pressure would be slightly different for the different weight/surface texture
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ilovefire
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Thu Nov 25, 2010 3:58 am

more_eggs wrote:This is true.. Ill grab some metal bb's tomorrow, but I imagine the pop off pressure would be slightly different for the different weight/surface texture
only if the textures are vastly different it might make an effect its more size even a little bit different will affect its pop off
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more_eggs
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Thu Nov 25, 2010 5:19 am

what are the chances of something like this
http://cgi.ebay.com.au/Car-12V-Electric ... 714wt_1184

actually getting to 300 psi?

Even better, just found out I have access to two working portable air conditioning units.. Im thinking these would have some form of compressor in them?
Last edited by more_eggs on Thu Nov 25, 2010 5:44 am, edited 1 time in total.
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