Carbon fibre barrel help

[jackssmirkingrevenge]

Heh ya I poke my head in from time to time, probably more frequently now that I'm working in a CNC shop

That augurs well

I'll have to put it together since I've been working on it recently, but I believe a few pictures could be provided in the next couple days. Ghastly little thing though, blows your ears out with larger bores (.40 and .625) without ear protection, and airsoft BB's go really fast out of the arrow barrel. I'll have pics up soon...

Sweet... is there some method to fuelling or is it just a quick burst from the torch nozzle into the chamber?

[Spudinator]

Yah, you'll see once I get pictures up in more detail but I use a small jewelry torch (harbor freight but it rocks, their more costly items usually do) with a number 3 tip on it, fits into the threaded chamber port nicely. Just set a good neutral flame and snuff it on a piece of wet wood, then give the gun a 10 or 15 second shot. Shoots every time without misfires, which is nice.

I'll give the gun a rundown so you have an idea of what it is.

Two ounce steel Co2 cartridge for the chamber, roughly ten cubic inches. These don't use standard Co2 threads, its more of a combo of 1/4" NPT size threads (straight though no taper) with the nipple-pierced burst disc of a 12 gram cartridge. I drilled the insides out to around .400 or so. Ignition housing/grip are an old paintball gun handle with the trigger modified to depress a small piezo clicker, the kind found in BBQ grill lighters. I had to weld two 1" long 10-32 studs to the chamber to attach the handle. The fuel port is a 1" long 1/4-20 nut welded over a 3/16" hole near the breach, pointing towards the back of the chamber for mixing. I had to machine a poly/PTFE sparkplug to fit between the handle and chamber, its got a bolt going through with the head lathed round, to fit inside the 3/8" hole I drilled for it. A nut on the bolt is then tightened until the plastic swages out and seals everything strong and tight. The hole was thoroughly deburred to prevent cutting the plug.

That about sums it up, but like they say pictures are worth a thousand words... soon to come.

[jackssmirkingrevenge]

That about sums it up, but like they say pictures are worth a thousand words... soon to come.

Yup... burst disk though?

[Spudinator]

So here is one pic for now, I'm on my lunch break so I don't have a lot of time. More to come...

<a href="http://s1333.photobucket.com/user/Spudi ... 2.jpg.html" target="_blank"><img src="http://i1333.photobucket.com/albums/w63 ... c33612.jpg" border="0" alt=" photo ResizedImage_1370548192246_zps13c33612.jpg"></a>

And no burst disc, just a hole.

Edit... more has come.

<a href="http://s1333.photobucket.com/user/Spudi ... 9.jpg.html" target="_blank"><img src="http://i1333.photobucket.com/albums/w63 ... cadee9.jpg" border="0" alt=" photo IMG_20130605_200047_zpscacadee9.jpg"></a>
I'm shining my flashlight through the poly to show the spark gap. Notice the swelled plastic, its about a 1/4" wider than when I stuck it in after machining.


<a href="http://s1333.photobucket.com/user/Spudi ... 9.jpg.html" target="_blank"><img src="http://i1333.photobucket.com/albums/w63 ... dfb0b9.jpg" border="0" alt=" photo f77dfe07-ed3f-4005-a63d-125b8d2cd9cd_zps09dfb0b9.jpg"></a>
Overall a pretty simple little device but loads of fun, if used safely of course. It packs a lot of whoopass and can cause a lot of damage if used improperly. I'll just say this, to the younger audiences, leave this one to older and more experienced builders. It requires machining equipment, a very good welding machine, a very good welder, and a bit of know-how to retrofit the ignition into the paintball handle. Not to mention confining oxygen and acetylene is a serious thing no matter what situation, so be safe.

JSR, I'll eventually make a thread in combustion showcase with a few vids of it in action. Its not 100% complete, after some modifications a while ago I'm missing a few pieces. So once I get it all together I'll try and get it up.

[jackssmirkingrevenge]

How wonderfully post-apocalyptic hope we get to see it in action