SpudFiles

nice pneumy, try the sprinkler valve trouble shooter? It helped me heaps when I did my sprinkler valve.

JSR: there hasn't yet been a situation that you havent been able to post some kind of crazy/funny pic. Good show

Did you get the right type of threaded barb? The threads although highly unlikely may be different styles.

They screw in perfectly, there is just a slight gap, so that when I pump it up to anywhere over 40psi and stick the blowgun into a bucket of watter, there are lots of bubbles coming up.

Here is a picture of where the leak is coming from. I don't think that there is a crack because that doesnt seem to be where the leak is coming from, but correct me if I am misunderstanding, that the crack would be on the blowgun, or would it be on the hose barb?

I've had a brass fitting crack on me, it was hairline, I could hardly see it at all.

Did you wrap the brass fitting in teflon tape?

Lentamentalisk wrote:I have tried resealing it with PTFE tape, as well as the gooie pipe thread compound, neither of which worked.

yes I did

Ah right so you have, I can't see any teflon tape on the fitting at all, so maybe put some more on or do the underwater bubble test to see if the fitting is leaking or cracked.

mtronic wrote:JSR: there hasn't yet been a situation that you havent been able to post some kind of crazy/funny pic. Good show

chances are that if you've thought of something, then a) so has someone else b) they've made a picture about it and c) you can find it with google image search

MrCrowley wrote:Ah right so you have, I can't see any teflon tape on the fitting at all, so maybe put some more on or do the underwater bubble test to see if the fitting is leaking or cracked.

sorry of the confusion. I just screwed the blowgun on to show where the leak was from. I had already taken it apart after the leak to see what was wrong.
I guess I have to admit that I bought the valve off of BCARMS, and it leaked when I got it. I will get in contact with the owner asap about it.

edit: Contacted, and Brian sent me a new blowgun and hose barb to replace the faulty parts! That is what I call great service!

New Damage Pix!

block of balsa that I shot. Veered up because of its instability, embedding itself in the chair I used as a safety net. (later to be used as a sabot for small heavy things)


Sharpened bolt


Bolt in tea light sabot


No penetration because the bolt didnt hit straight on. Looks like it never even left the candle


Shotgun shot of nail darts with string taped on their ends to make them fly straight, using a home made sabot made out of stiff paper


Fairly accurate if I do say so myself


Using the block of balsa for a sabot because the one I made got crushed when the boards fell on it. Not so accurate : )


Firing a ~1"x1" piece of metal bar that I found in my school's weight room, with the balsa as a sabot (no pic of ammo, because I lost it). Exit hole:


Where it bent the chair out of the way as it passed through unhindered, never to be found again:

I just got a chrony for my B-Day and so I decided to clock this old cannon. To my suprise, it was far better than I though it was. Here are the results:
80psi: 299.9fps
100psi: 339.5fps
125psi: 338.0fps
140psi: 408.7fps
Here is my setup:


Videos:
80psi shot
100psi
120psi
140psi

Cool pnuematic
nice and simple
I am also very surprised ny the chrony results, with a chamber that small I would have excpected much lower results
But the more power the better I guess

MrCrowley wrote:I've had a brass fitting crack on me, it was hairline, I could hardly see it at all.

I've had brass fittings hairline crack on me too. All it takes is a leveraged hit or drop at the wrong angle and you're screwed.

Also check to make sure your threads are burr and gap free in your blow gun.

Its all working now. Turns out it was the piston/diaphragm thing. Where the screw was that held in the rubber sealing face, there was a big o'le hole. Filled it with GOOP and its all better.

Good video, I wish I had a chronograph.
400 fps is fast for a tennis ball too. 8)