SpudFiles

You should use a aluminum barrel...You can get sch 80 pipe any lenght at ( onlinemetals.com) sch 40 3/4 in x2-3 feet long or sch 80.....

You should use a aluminum barrel...

Wtf why should he this gun is near perfect as is and a aluminum barrel will ruin it's "copperyness".

There is no known advantage of using a alumninum barrel over a copper one.

And aluminum is more expensive any way.

Online metals.com? plumbing supply.com? were your last two posts.

What are you? A spam Bot?

And aluminum is more expensive any way.

UMMM, explain to me why 10 feet of 2 inch copper is..... 150 bucks..........

aluminum is way cheaper.

Alas, I don't have the opportunity to order from the US. I live in England (That is England as in a part of Great Britain or the UK, not "New England") so I can't order cross atlantic
Still, copper works very well for this job, and I wouldn't want to change to an aluminium barrel - as Zen said, it would destroy the "balance" of the launcher.

@Zen: Near perfect? Bloody hell, I'm cooking on gas with this launcher - it's had a very good reception.

aluminum is way cheaper.

WTF!!! I thought copper was cheaper!!!
I spent (a large amount of money) on my copper gun thinking that I was saving money over a aluminumm one!!!!!!!

Aluminum is the most abundant metal in the entire universe. It had better be cheaper!

well its not

This vid was awesome, made my day. Again, very nice work.

Solar wrote:Aluminum is the most abundant metal in the entire universe.

Actually lithium is if you want to get technical.

sandman wrote:Actually lithium is if you want to get technical.

Or is it iron ?

@Zen: Near perfect? Bloody hell, I'm cooking on gas with this launcher - it's had a very good reception.

Well saying it's nice/cool won't get us anything, since it's your launcher.

Well, compliments get you more videos... in fact, given the decent response, there will indeed be another one, but longer, more reliably edited, and with a bigger budget (The budget for the last one summed to a couple of quid for batteries for the camera, and a few rounds of ammo from my stash).
It's going to be a pretty comprehensive video, showing damage, penetration, accuracy, and a few other things.

I'll also do a couple of upgrades to HEAL to give it a little more power, as well as taking of those efficiency suggestions JSR sometimes has to their practical extremes. Dead space could be pinched slightly, and the piston and pilot volume might be adjusted a bit, which would also shorten the launcher slightly (gotta love soldered copper. Couldn't do half of the changes with cemented PVC) - time to really earn that "High Efficency".

Expect the video in the fortnight leading up to Christmas.

Personally I think you should get rid of the ball valve on the barrel, with your other safety, you don't really need it.

I've had the suggestion before, but I take safety seriously, and it doesn't have any real negative impact on performance - so I'm not one to risk an accident.
The other safety is useful, but the barrel safety is the only one I can be sure will absolutely 100% stop the launcher firing when I don't want it to. There are other problems that might arise that the trigger safety will have no control over.

There are however other improvements I can make in that area...

More talking about planned changes to HEAL I'm afraid, however they're good ones.

I can work on valve flow, piston design, pilot volume and dead volume a little, but this will do only so much.

The pilot volume and dead volume are already pretty good - there is some work that can be done, not much though without major changes that would affect other things. These changes only equate to relatively small amount more power, maybe a couple of percent.
The valve flow can be improved. It's better than any other valve I've made in this size, but I believe I can still get more and cleaner flow through the valve. This is the main improvement I can make in the valve area, and hopefully it would add a significant few percent to power.
Piston design needs to remain largely unchanged, but I may be able to decrease back flow a little more, and trim a tiny amount off the weight.

Still, all these changes are small game, only adding so much, as I spent quite enough time before working on things like this to get them good in the first place.
The big change I'm hoping to make is a transition up to 25 bar (360psi) pressure, rather than the 21 bar (305 psi) I normally work at (22 bar [320 psi] is possible, but very hard to achieve). I have a plan to get the pressure from a 120 psi compressor - I'll say more later.

With the extra pressure and the changes, HEAL should be able to give a lot more than it already does. I'm still a long way short of 4 figure muzzle energies, but to get 1000J (let alone 1000 ft-lbs.) with a hand-held cannon in a low bore size would be nigh on impossible.

I'll also make some longer (but less portable) barrels for really blasting something.

Any thoughts?