SpudFiles

Neat video editing, neat cannon, smooth operation, great job, really excellent.

lol I almost missed it... it looks great

Great one, what's the length of your chamber please?

That looks really good. really powerful too. i never see many copper combustions. The muzzle brake is a nice touch.

thats epic!!!
do u have any detailed blueprints?

I know this is an older post. But i was thinking of making this with my son as a "father/son" project. He is 13 and just now letting him mess with the boom-boom . He helps me setting up the fireworks shows and stuff we do. And is interested in starting on these. Do you have any "Plans" for this. it actually seems pretty straight forward. But i was wondering if the bike pump was necessary? With a 10x1.5v power supply i would think the fan itself would purge the chamber nicely. And speaking of the 10x1.5v could you use 2x9v much smaller. Heck even now they have a 12v battery that is like half the size of a AA. Not criticizing by any means so please don't be offended just a few thoughts i had. Any help or advice would be great. Thx.

No plans i'm afraid but as you say it's fairly simple, although this is a spare parts gun built from bits I had lying around not standard parts.
I would say the pump increased reliability a lot, axial fans don't work very well against a high back pressure which is what I have here as there is no large inlet for fresh air. Instead the fan and pump work well together to purge the chamber and the fan also provides turbulance to increase the burn rate. what most people do is add a large ball valve to their chamber which is opened to help the fan vent the chamber, however I did not do this for aesthetic reasons.
As for the battery pack, yeah a 12v would do fine, this was just a rechargeable NiMH pack i had lying around which I knew could source enough current to keep the fan at full output for a long time.
The more standard combustion would be something larger built from readily available PVC parts but if you're after something that will take more than an afternoon to put together and be a bit more durable i can see why this might be a more attractive propostition, good luck anyway

Ahh i see now. I did not take in to account the lack of an exhaust "valve" I can see now why you added the pump. Like i said I'm new to the mapp/propane guns. I have made the spray and pray guns for ever. And am now working on my first pneumatic one with my son. Once i pick up a few parts for the copper one i will send you a pm and maybe we can collaborate on the build. Thx for the explanation on the pump.

What are you planning on using for the chamber? copper pipe and fittings that size are prohibitavley expensive where I live so I used aluminium, this meant I had to make a custom endcap which was cross bolted into the end of the chamber. Can I ask why you want to use copper not PVC? It will make your life difficult

Difficult? LoL "Hell if it was easy everyone would do it" But seriously I think just the aesthetics of it. They look so much more (for lack of a better term) intricate. And i thought they could hold more psi. I was wanting to make one with a higher velocity. If this isn't true i will gladly stick with the pvc. A 8'x1/2" copper tube is 20$ so the price is increased exponentially. This doesn't include the chamber or solder or anything else lol. Maybe it can be something i save up for or when taxes come in next year:). Ill have plenty of time for planning by then.

I was wanting to make one with a higher velocity.

This is allready a very powerful combustion gun. If you want high velocity, go pnuematic.

The peak pressure obtained in any atmospheric combustion is going to be similar whatever the construction material.
If you want higher velocity you should be looking at a pneumatic or hybrid as qwerty said, then you would definately want to be avoiding PVC. If you want higher energy just scale this design up.

If you want high velocity, go pnuematic.

Interesting reasoning, considering that the maximum attainable speed for an unheated single stage pneumatic is around 1200m/s, while it's roughly twice that for a combustion. Might want to check your numbers there, qwerty

But seriously I think just the aesthetics of it. They look so much more (for lack of a better term) intricate. And i thought they could hold more psi. I was wanting to make one with a higher velocity.

I recommend using an oxygen enriched mix, even pure oxygen/propane. You'll get over twice the maximum pressure, a hotter burn, and absolutely no headaches with ignition, a welcome change for starter designs. Copper will be well suited to the higher pressure these mixes produce (about 260psi, versus 120psi for air/propane), and the relatively small size won't be too much of a hog on the oxygen. This allows higher peak pressures without the relative difficulty of building a hybrid, and is quite safe with reasonable chamber dimensions (long, skinny chambers can cause detonations).

Ok so in short. I need to go combustion. But not use pvc. Aren't all the cannons on ultimatespudgun.com PVC? If not they shore look like it. Maybe i can do a metal chamber to pvc barrel. I need to read more on the pneumatic's what i just built was pneumatic but low pressure/velocity. Thanks for all the advice guys. I have more reading to do. LoL.

wow thats amazinng, thats like a pneumatics power great build to0...I like the breech