pneumatic marker project

[jackssmirkingrevenge]

You know I do a lot of scrounging and occasionally incorporate standard fittings, but it's not always practical, especially in this case where I needed to fit everything in a marker.

Back to the subject of this thread, it's currently curing (for the second time *sigh* some epoxy leaked into the pilot chamber first time round...) and I've found a way to greatly accelerate the process by using one of the laboratory ovens at 50ºC

[JDP12]

Ah... Very good idea. Can't wait to see the results!

[jackssmirkingrevenge]

Tried it out at 250 psi, it works! 16 grain 0.22" pellet chronied at 165 feet per second, that's around 1 ft/lb, we'll see what it does at full pressure. Before trying that out though, some more epoxy reinforcement is in order

[JDP12]

Sweet! Pictures?

[jackssmirkingrevenge]

When it's finished, though really it's a marker with a schrader where the felt tip should be I'll try and do some damage videos too. Might take a few days though, the xmas round of liver abuse starts at 10 am tomorrow

[jackssmirkingrevenge]

here's a quick test at 400 psi, 227 feet per second with a 16 grain pellet, that's almost 2 ft/lbs

[youtube][/youtube]

Tests at 800 psi to follow eventually, and adapting the cap to pilot to schrader. I've been thinking about the concept and it could be extended to a three marker unit, held together by threaded fittings. One marker could be as above, another one would be a barrel extension and the third could be a suppressor.

[inonickname]

Very nice, especially given the size.

If you used telescoping tubes for the barrel you could probably make a removable insert for smaller calibers (aka- a longer barrel) and higher performance.

Several other ideas..when you do some penetration tests (and assuming you're an assassin) the nicotine loaded pellets may be feasible with this- or simply a small dart with a discarding foam sabot- I'm sure you can get strips of foam in roughly this size for some use.

Good work

[jackssmirkingrevenge]

Several other ideas..when you do some penetration tests (and assuming you're an assassin) the nicotine loaded pellets may be feasible with this- or simply a small dart with a discarding foam sabot- I'm sure you can get strips of foam in roughly this size for some use.

I have no such ambitions so this discussion is irrelevant

Some testing at 800 psi, it didn't blow up (yay!) but performance seems to be limited to 275 feet per second with 16 grain pellets. I expected a bit more, of course the 850 psi given by the tank is nominal and I have no way of verifying this output, and my "filling station" doesn't actually press the schrader stem, relying on pressure difference to crack the valve open, so of course some pressure is lost at that stage too. Using "modded" valve stems there wasn't much of a difference in performance, it maxed out at 283 feet per second. Not exactly a powerhouse at less than 3 ft/lbs but you don't want to be hit by it.

Here's a detail of the marker and the paintball tank attachment I made, using epoxy (what else?) and an aluminium car tyre valve cap.

[JDP12]

Very nice jack... I like it

[sparktech]

I am sorry if this seems stupid to anyone but I am new to making pneumatic pen guns...how exactly does this work?? do you have to pump it at all?

[jackssmirkingrevenge]

I am sorry if this seems stupid to anyone but I am new to making pneumatic pen guns...how exactly does this work?? do you have to pump it at all?

I would recommend being patient and having a careful read through this thread.

If you still have any questions after that, feel free to ask.