Cannon Accumulator Help

[jazzman56]

I now that i need to do my own trial and error in working out how to build and go about designing my air cannon but after months of reasearch i have got nowhere far. Many hours riding back and to Bunnings i have gone through at least 3-5 different plans on how to build a steel paintball cannon. As a last resort i have come here to ask a few questions (as it's getting bloody frusturating)

My problem is finding a suitable accumulator or pressure vessel.

I had purchased a fire extinguisher (made by FIRESENTRY AB powder type ) believing that the threads would be standard 25 mm (1 inch) though instead they are a custom non standard thread that's a little smaller than 1 inch. I have been to no less than 4 specialty stores (reece, eletrical store, special pneumatic stores, plumbing supplies etc) and have found no fittings that fit into it.


The paintball cannon would have:

Valve: 3/4 inch QEV (Ebay) or homemade piston valve
Pilot: 3/4 inch ball valve
Paintball barrel: (Ebay)
http://www.ebay.com.au/itm/TL-05-Paint ... 678wt_1139




My questions are:


Is there anyway i can modify/epoxy in a smaller thread into the extinguisher?

Or a cheap accumulator online (Australia) or i'm happy to buy one from someone?

and

Will i be able to get the paintball barrel into Aus? If not whats best to use?

Thanks

Jazzman

[jackssmirkingrevenge]

Is there anyway i can modify/epoxy in a smaller thread into the extinguisher?

You could conceivably make it as attached, I've done similar things for high pressure projects, you need the right epoxy though for a safe joint.

Will i be able to get the paintball barrel into Aus? If not whats best to use?

Probably not, maybe find a paintball blowgun? Also if 20mm plastic conduit piping is available, at least here in Europe the diameter seems ideal for paintballs.

[jmez1996]

try a smaller propane tank? would work the same way and you could get a thread adapter easily so you dont have to worry about using epoxy? you can get them from bunnings or find a second hand one.
like these: http://wolfstone.halloweenhost.com/Hall ... eTanks.jpg

[Crna Legija]

My one's threads were a tiny bit bigger than 1/2'' bsp so i just epoxied a 1/2'' male to male into it and its held 650psi at least 150 times now with out fail, i have a co2 type of FE but it will work for you to. If your one is steel then you have to paint the inside with anti rust paint to stop it rusting and possibly coursing it to fail.

If you want to make a paint ball gun you not use a 3way valve to pilot your QEV and go semi. You can load by hand for now until you are confident enough to make auto loader mech.

paint ball barrel i doubt it unless you have a gun licence and own a paint ball gun, with you posting this i dont think you do.

how big of a tank do you want? and what kind of pressure does it need to handle?

[Technician1002]

In the US the propane tanks are threaded 3/4 inch pipe thread. All sizes of refillable tanks with the standard valve have the same threads. I have tanks from 1 gallon to 8 gallon. (5lb to 30lb)

[mattyzip77]

Tech do you know if they make a fitting so you could attach a forktruck propane tank to a gas grill?? I have looked, and have had no luck. Reason being, I have access to a big supply of them and I reckon one of those would last me a whole year!!

[Technician1002]

A forklift tank delivers liquid to the engine so the gas draw does not cause the tank to get cold as it boils off propane to make vapor. For this reason the valve is different to prevent you from connecting to an appliance and freezing the regulator with liquid and having an explosion due to liquid passing through the regulator. The engine can use liquid as the regulator uses engine coolant to heat and vaporize the propane.

This thread covers the difficulties of someone connecting a forklift propane tank to a turkey fryer and didn't understand this. That tread has the newest post on top so read it from the bottom up.

http://www.bluecrab.info/forum/index.php?topic=5013.0

You can buy a larger tank if you need to. Propane tanks come in many sizes. Don't use one that delivers liquid.

thats not the right kind of propane tank to use for cooking.
the propane tanks on forklifts are meant to use liquid form not gas.
if theres one thing you should never attempt to mess with,its propane.
if you have no knowledge or any training in it your better off calling a professional.
its not like changing oil or running electrical.propane doesnt burn it explodes.
therefore save your house from having to be rebuilt and most importantly save your limbs from being blown off,unless of course you like to eat crabs with fingers and legs with them.

[Crna Legija]

maybe you can use the forklift tank to fill a standard tank?

[jazzman56]

Hey, it's been council clean up and while looking for an fridge compressor i came across an old LPG cylinder made by jackaroo.

The cylinder is 2kg and has standard 3/4 inch threads (i hope or EPOXY),

BUT the cylinder is 14 years old rated to 3.3Mpa. Though cylinder has one scratch on it, would it be still OK to use????

Photo,

[jackssmirkingrevenge]

BUT the cylinder is 14 years old rated to 3.3Mpa. Though cylinder has one scratch on it, would it be still OK to use????

An external scratch is of relatively little concern, remove the fitting and try and inspect it for corrosion internally.

[POLAND_SPUD]

and has standard 3/4 inch threads

Most likly it has left handed threads

[jazzman56]

Damm, I've tried for like 30 min with no success, with bruises on my palms as a result. Damm thing is smothered in lock tight.

Any other ideas of an accumulator, would a (ELECTRIC) Pressure Washer (handle and all) have a inbuilt pressure vessel, cause i found one of them as well??

What fire extinguishers have standard threads, that i can get in AUS??.

What cheap propane torch kits can i get??? (might just make it out of copper soldering it)


SORRY for the million questions,

Mann this is getting frustrating, i have spent no less than 20 hours looking online and such for a suitable accumulator for my new barrel sealer piston valve.

Edit: When i build my valve can i use BRASS hex nipples as it's been mentioned in another thread that they fail at 200psi, if they do what do i use instead.

Thanks for everyone's Input

[jackssmirkingrevenge]

What sort of volume are you looking, to what pressure do you intend to fill and what's your budget?

[POLAND_SPUD]

Damm, I've tried for like 30 min with no success, with bruises on my palms as a result. Damm thing is smothered in lock tight

were you using a wrench to do that ??
sorry just making sure

IIRC they use some sort of sealant on them, sort of like loctite
Though I have no idea if heating the joint would help

Check the fitting for threads - don't worry if it is left handed thread you can get adapters to standard bsp

[jazzman56]

VOLUME: Most likely to be around 500cm3 (for marshmallows etc.) But i'm willing to get anything around that.

Pressure: The higher rated the better, though around 0-300 psi (when i finally get round to making my PUMP)

Budget: I'm willing to spend up to $10-20 on the accumulator itself.

Thank you JSR