Choices choices…
Ok, my valve seems to be doing pretty good but the fps deviation is a tad more than I’d like (14fps). I’m getting similar upper-numbers from both of the following:
10mm of spacer with a 100g hammer.
17mm of spacers with a 50g hammer.
Which config would offer better long-term consistency do you think?
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You know Lang, I remember reading about the guy that had his tank heat up while filling it. If I am remembering correctly he had changed out the valve seal for a delrin seal and the rush of HPA past is created an intense amount of heat…..could your delrin be reacting to the High pressure rushing by and getting hot?
The other circuit-board is busted. Tried soldering the broken pin, soldered ok but the display still shows an error. 🙁
I’ve dropped pellets through the good one and it seems to read them fine (2fps 😆 ).
Maw, the heavier the pellet the more air you’ll use, and you’ll see a faster and more significant shift in FPS. At least you’re getting a good solid consistent bell-curve, which shows your setup is working well.
hey, you never know till you try it,but you are so close, I shouldn’t talk though cause I’m really lazy too, I’m shooting the 37 eun jins at 850-940 and back down to 850, on the low side of the tank, 2500 max., it goes something like this- 850,870,875,880,890,899,908,920,920,930,940,940,930,930,920,910,900,900,895,890,890,888,880,875,875,868,858,855,850. I have decided it is time for some cleaning and lubricating, but I’m lazy, I’m really suprised at the lenghths you are going to on these tests, with all the pumping and taking the gun down everytime to change the spring tension, I really should do a full string on the chrony instead of just throwing numbers out, but I have shot up all my 37’s, I could use 42’s, or 26’es maybe when it gets light I’ll run a string and we will see how it is shooting now.
Here we go again…thought I’d knock a couple out before changing stuff, just to confirm consistency at 2600psi and in four shots I got 990, 1074, 892 and 815.
I am now officially baffled by this. The valve is absolutely 100% free-moving, no stickiness anywhere, under any kind of forwards and/or sideways load. The hammer is 100% free-moving, the breech is slick and any air loss is so minimal as to be irrelevant (had more on an old stock setup that didn’t cause these kinds of fluctuations).
So one is left thinking “something is happening inside the valve when it’s under high pressure, something that can’t be replicated when it’s out of the bottle…”
But I can’t think what. Air cannot get up the outside of the plug (which, theoretically, could cause it’s walls to press in against the stem and retard it’s movement). If anything the air would get up between the internal wall of the plug and the external wall of the stem and create a bigger space, allowing the stem to move more freely. And then blow air (which I see, a little). But this same issue has been happening with the air-tight plugs too. Then I considered that maybe the air is blowing out the walls of the stem (they are 0.5mm thick), but steel does not perform like an elastic…if they were blown out they would stay blown and I’d feel the increased friction when I moved the parts together by hand.
I’m beginning to think in the realms of quantum-physics and consider that maybe something happens to delrin at an atomic level when subjected to high pressures and it generates an intense magnetic field that causes a significant effect on any steel in the immediate vicinity. 😆
Maybe my chrony is malfunctioning, it’s been bounced across the yard enough times. But it’s solid-state. I do have another circuit-board for it, I think I’ll swap them out and see what happens. 😕
Being lazy I’ll try the 15mm again, as I’ll have to go cut a 16mm if that’s what it needs. Pablo has a full set I made for him but all I have currently are 15mm, 13mm, 10mm, 7.5mm and 2mm.
But I think you’re right.
Seems too be pretty consistant at the moment, maybe 16 mil.
No power-wheel, I use spacers (17.5mm of them at the moment, I’ll be reducing them when I test some more).
Alittle more power that time, what do you run the powerwheel at, or do you have one?
Yea I lost 20lbs and bulked up the first 4 months I got into PCP’s…
It’s good for ya…
have the tolerance to make parts with that kind of tolerance…
Fine work Lang…
The good bit is it obviates the need for an o-ring around the stem. I’ve done a couple before and they worked fine, but on Pab’s original valve it kept gripping the stem on the firing-cycle and dumped the tank. Seven times (seven attempts to fix it, nothing worked). Thank feck he’d bought a scuba-tank or we’d have been done in.
Yea i could see how that would be a tough one to solve….I tell ya there is
nothing like a compressor when you’re testing….I wouldn’t sell mine or a
mil…
I have to fill my bottle manually each time I need to do something in the valve. I look like fucking Popeye. 😆
have the tolerance to make parts with that kind of tolerance…
Fine work Lang…
The good bit is it obviates the need for an o-ring around the stem. I’ve done a couple before and they worked fine, but on Pab’s original valve it kept gripping the stem on the firing-cycle and dumped the tank. Seven times (seven attempts to fix it, nothing worked). Thank feck he’d bought a scuba-tank or we’d have been done in.
Yea i could see how that would be a tough one to solve….I tell ya there is
nothing like a compressor when you’re testing….I wouldn’t sell mine or a
mil…
have the tolerance to make parts with that kind of tolerance…
Fine work Lang…
The good bit is it obviates the need for an o-ring around the stem. I’ve done a couple before and they worked fine, but on Pab’s original valve it kept gripping the stem on the firing-cycle and dumped the tank. Seven times (seven attempts to fix it, nothing worked). Thank feck he’d bought a scuba-tank or we’d have been done in.
AAAHhhhhhhh…….I finally have a picture in my head…Now I understand…That is Swiss watch movement stuff right there…I don’t
have the tolerance to make parts with that kind of tolerance…
Fine work Lang…
I want to see that stinkin valve and apeture plug…lol
It’s not much. Originally I had the aperture drilled directly through the base of the brass valve-body, but the stem wasn’t a good fit and it was blowing a lot of air on Pablo’s setup. I gave him my good valve and used the other to experiment with a 10mm stem. That didn’t work, so I was left with a valve-body with a 10mm hole through it. I rescued it by filling it with a plug and cutting the stem-bore and aperture into the delrin. The plug is held in place by tolerance-fit plus vacuum (and if it wasn’t the bottle wouldn’t hold air). It’s a bit tricky getting the stem and delrin bore to match closely enough that air doesn’t blow but the parts also move freely enough to not mess up consistency. The last two I lapped them in with micro-compound, but the third one (the 5.5mm) I was getting the hump at that point and ran the drill in real fast until it squealed, which over-heated the delrin, made it expand and cut too much. The stem didn’t need lapping, let me put it like that. 😆
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When you have the valve out are you lubing it and then put it back in? maybe, the lube with heat, and delrin, some how cause the valve to swell alittle ,hell ,I don’t know your theory on magnetics sounds good to me.