SpudFiles

quite complicated lol to explain but here goes.......

a 3" by 3.2m chamber with end cap leading to a 3" to 1.5" reducer, then a 1.5" by 5" piece of pipe leading into a 1.5" elbow then more 1.5" pipe then into another 1.5" elbow 90 degrees in total making a 180 degree bend lol........ then a 1.5" by 5" piece of pipe leading into a 1.5" ball valve then another peice of 1.5" pipe about 3" long leading to a 1.5" to 2.5" reducer which then finally leads to a 2.5" barrel 4ft long !!!

would this work and be reasonibly powerful at 100psi

oh and sprinkler valve is out of the question lol cause in england a 1" valve is 100 pounds which is nearly 200 bucks lol.

thanks alot guys

It would be reasonably powerful, but you could get away with this:

3" chamber, 1.5" coupler, 1.5"reducer, 1.5" male nipple, 1.5" Ball Valve, 1.5" male nipple, 1.5" to 2.5" reducer, 2.5" coupler, 2.5" barrel

Didn't you have a similar thread to this?

nah that was a diffrent design which apparently had no hope in hell

First, you could order a sprinkler valve from the states and spend maybe 12-15 pounds after shipping, not to mention it would be way better to use a 2" BV(ball valve) which will cost at least half that, double the cost quadruple the performance. What you described is really common on this site, but a 3.2m chamber is gonna be really big for a 4' barrel, with BV guns you need a long barrel, because with what you described, the ammo will be projected a long time before the valve is all the way open, meaning your shot will be extremely weak. I would recommend burst disks before a BV, but you could try to make a piston valve, cheap and the best of the 4 common valves(sprinkler, BV, burst disk, piston) there is plenty of tutorials if you search this site.

also you could simplify your design using "street elbows" which are elbows which fit inside one another, lose all the 5" this, 5" that, keep your flow constriction minimal.

Head over to http://www.uksgc.co.uk!
There's loads of information for UK based gunners.
Have a look at my copper gun(http://www.instructables.com/id/Copper- ... ir-Cannon/), it's a great beginners gun and will get the most power out of a ball valve (because it's floor mounted). The videos on youtube are only 80psi. At 160psi it is absolutely excellent and will shoot a deactivated .50cal bullet through a saucepan!
Don't bother with a sprinkler valve, they're a rip off here, best to get a QEV (quick exhaust valve) or a ball valve.

k first u gotta open your eyes dude a sprinkler valve here is like what 10-20 CANADIAN DOLLARS then shipping to your i am sorry but heavily restricted country which is going to cost about 15 CANADIAN DOLLARS so your already saving big and if u want order your pipe too because trust me man no matter what others say a "nub gun" is not worth over 50 bucks

Please, say that again with correct grammar.

Dearest pocket, I am not totally sure what you are saying because your grammar and syntax is quite poor, but if you are suggesting shipping a length of pipe across the atalantic then you are more of a fool than I thought. Why pay 45 "bucks" for an overrated valve anyway? if he really needed power like that he could get a QEV for just £10 ($20) in the UK!

If you did some research you'd know that a sprinkler valve shipped from BCarms would be over $50 and would have NPT threads. Useless thanks

Biopyro wrote:If you did some research you'd know that a sprinkler valve shipped from BCarms would be over $50 and would have NPT threads. Useless thanks

NPT threads are fine for the last time. It's only 120PSI max you'll be using them too. BSP will still thread into the valve just fine. Trust me, I bought 4 in America and have had no problems with them.

And yeah if you bought a valve from BC, which are about $22 (IIRC), you'll pay about $14 for shipping, so $36USD all up.

lol sprinkler valves aren't over-rated they are perfect for beginner guns as they can easily be modded, also setting up a QEV isn't that easy for a beginner trust me ive been there i had to set that project aside and try it in a couple of months. one other point even though i keep chopping at the ball valve it is great for a beginner gun because as said before they are cheap and can be interchanged with a sprinkler valve if you got the right threads

sorry for the bad grammar although it wasn't bad i was in the middle of MSN

I was not aware that NPT fitted BSP, thanks MrCrowley, but as for the shipping, I checked BCarms and it worked out as $51.98 (£26.10) to ship a sprinkler valve to the UK. A 1" PN18 ball valve is about £10 and £5 for PN10 here.

For a first gun it would be alot of cost and even more hassle to ship a sprinkler to the UK. There is nothing wrong with using a ball valve for your first cannon, granted they dont have the best opening times in the world, but thats isnt exactly the biggest problem when its his first cannon.