Originally Posted by xluben

i've been working on trying to put together a mechanical ion for a while now.
tonight i finally got it all assembled and it seems to be working. only dry fires
thus far. will test with paint/chrono tomorrow.

my mech ion is based on one done by Ydna of www.zdspb.com

http://www.zdspb.com/customwork/mechion.html

he helped me a ton throughout the process. i sent him several e-mails and all
received very helpful and timely responses.

my design varied slightly from his, though. in all it's configurations his mech
ion's firing chamber had a direct line coming from the reg (externally). i
wanted to keep it all internal, and came up with this design:



i was unable to find a 5/32" (x2) to 1/8" (x1) reducing tee, so i had to use a
5/32" tee with the third output threaded with male 10-32 threads and a 1/8"
adapter onto that. it took up a bit more room and made mounting somewhat
difficult. i do not believe any manufacturers normally make this part.

as you can see, the plumbing is fairly similar to the stock setup. the tee
fitting goes in the physical position of the solenoid, but the 3-way is what
reproduces the function of the solenoid (vent the forward chamber when
trigger is pulled). with this setup the bolt is held forward as long as the
trigger is held down, so a bolt with dual tail o-rings is necessary.

after several attempts at making a mounting bracket to hold the 3-way
behind the trigger i decided to try and use set screws (like many pneumags).
here's a picture of the 3-way mounted:



and here you can see that the large tee adapter made it difficult to route a
hose to the input of the 3-way:



(and, yes, i did try shorter lengths of hose which all caused the hose to pop
off the barb on the 3-way. even with this length i had to use a mini zip tie to
help hold it on)

and here you can see where the 3-way hits the trigger:



it tried putting it as close to the pivot point as possible to allow for a very
light pull. right now it is (conservatively) set at a ~2.5mm pull which is
shorter than my vp scythe is set on my other ion (eletectro). currently it is
very easy to fan at 11-12bps (about the max i can fan any trigger), but it's a
little tricky to walk. i can get to about 14bps, but can't do more than about
1/2 second without a skipped shot and when walking it's pretty easy to short
stroke. depending on where my operating pressure actually ends up (to fire
a proper velocity) the trigger may become more walkable.

when fully assembled this mod is completely undetectable (visually):



last weekend i tested the setup with paint and got mixed results. it was
shooting wall (about 285fps at 150psi), but would drop down into the 240's
fps under rapid fire. BUT last weekend i was trying to use 1/8" hose (smaller)
to feed the firing chamber and did not have a bolt with dual tail o-rings (to
seal the firing chamber). both of these issues have been fixed so i am hoping
i will not experience any noticeable shootdown at least into the 10-12bps
range (and possibly higher).

p.s. i do know this mod is pretty much pointless. and it's almost guaranteed
that the ion will perform slightly worse even with this mod working perfectly. i
did it mainly for fun and i do like the feel of a pneumatic trigger. also i got all
parts (including the gun wo/electronics) for under $100.

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UPDATE (7/21/07):

shot the gun with paint today. chrono'd in the 280's fps at about 145psi
input pressure. under rapid fire i never saw a velocity below 260fps. this is
similar (if not better) than what warpig saw in there test of a stock ion:

http://www.warpig.com/paintball/tech.../testing.shtml

so i credit the regulator for this inconsistency/shootdown and assume that
the pneumatics are working properly with no airflow problems. there is not
any visual indication of drop off or inconsistency when shooting the gun. it's
actually very quiet with little to no kick.

i really like how the trigger feels. i've currently got it set at just under 2mm
and it's just light enough to walk. i can walk alright, but usually will short
stroke. fanning at 10-12bps is fairly easy. here's a vid i made of it shooting:



i will try playing with it tomorrow and see how it fares in a game. my only
fear is that i'll short stroke and cause ball breaks.

i should also note that it was brought up that since there is no solenoid it
will be less sensitive to liquid co2 pressure spikes causing major damage.
to test this theory i grabbed a regular co2 tank (no anti siphon tube) and
shot a couple hundred rounds rapid fire. the tank was very cold and covered
in condensation, but the gun still functioned very well. my only concern
with co2 is that it will freeze orings and cause leaks.

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UPDATE (7/23/07):

well, i played with it using Co2 all day yesterday and had no problems. put a
little over half a case through it, and it would not leak no matter how fast i shot
or how cold the tank ended up. i got about 900 shots off a 20oz. i also had no
chops or barrel breaks. but there is one issue, no safety! any ideas?

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UPDATE (7/24/07):

adjusted the position of the 3-way for the lightest pull possible.

here's a vid of me dry firing and walking as fast as i can. as you can see i'm
not really holding the grip, i was just trying to shoot it as fast as i could:



goldwaved at 15cps. unfortunately when i tried walking with paint i would
short stroke every few shots. it wouldn't chop, but would skip a ball (using
an egg III). if you do not fully release the trigger the bolt does not retract
far enough to let a ball drop in the breech.