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True micro bore

Started by Chickenthief, May 08, 2022, 08:31:05 AM

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Chickenthief

I have been given the daunting task of modifying a filling kit for the rest of a dumb family to use.
The thing is that the rifle is 200bar~2860psi and the tank when full runs above 300bar~~4290psi.
So most "micro bore" hoses i've seen runs 2mm~.078". That aint going to cut it for dimwits!!!
I am thinking more in the line of .25mm~.001" orifice?
Drill and tap the fill probe for a grub screw and drill said screw with a .25mm~.001" hole.
No runaway even if the bottle valve is opened fully, just a nice slow fill.

What say yee?

Alan

There is an Italian company (InterTraco) who makes high pressure hoses. I couldn't find what I wanted on their web site, but haven't called them. I mention them, as the hose which came with my Hill compressor was fitted with the hose you're looking for. It is slightly larger OD than 1/4" (≈6 mm?). The hose can be bought from Hill in England, but should be available from some US supplier. So a bit of searching should net you the produce you're looking for.
Alan

I have a Hill EC-3000 compressor. If you're a fellow Guild member, and you pass through Roswell, NM, I'll fill your tank as a courtesy (4,250 PSI limit).

rsterne

BTW, 0.25mm= 0.010".... just sayin'....

If you have the orifice at the gun end of the hose, and the valve is on the tank, where it typically is.... you will still get all the volume in the hose in the gun, it will just take a while for the pressure to equalize (into the gun).... To do this properly, you need to put the orifice on the tank side of the valve, the way Joe Brancato does it.... The problem with that is that being in the tank, any small piece of debris can get stuck in it, and you won't be able to get the air out of the tank.... You are left with a very dangerous situation, a tank that is full and can't be emptied....

I know, I've had it happen....  ::) .... In my case, the air would still leak VERY slowly out of the tank, and leaving the valve open for a week got the pressure low enough I could loosen the valve until the last bit leaked out around the valve past the O-ring.... I removed the orifice body and drilled it out to about 1 mm so that this could never happen again....

Bob
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