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PostPosted: Tue Jul 17, 2018 9:59 pm 
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Joined: Tue Sep 22, 2009 9:57 pm
Posts: 64
Location: Aurora, ON, L4G7X4
Anybody can help me tuning my air tank regulators for a 1200 psi output.

I have couple new regulators in my drawers from aliexpress got them last winter, but the outputs doesn't suits me, the discs (spring washers) are either too thin or too thick. Right now the two 48 cu tanks are different output, I would like to make them the same.
If somebody with first hand experience can give me a supplier and part numbers so I can just drop in the parts.
My problem is that I don't have a pump and taking the tanks to a scuba shop for refill...takes a lot of time to figure what pressure my heavily modded QB78 really likes.
I have an adjustable hammer spring on the rifle and can borrow a chrony. The last measured values were decent consistency about 750 f/s @ 700 psi with lighter pellets, now finally got a new batch of heavier 30+ g pellets these I am planning to tune.


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PostPosted: Wed Jul 18, 2018 12:11 am 
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Joined: Sat Nov 03, 2007 4:19 pm
Posts: 8936
Location: Coalmont BC
Generally, fine tuning a regulator is done with flat shims.... However, you first to have Belleville washers that will put you in the correct pressure range.... Every brand of regulator is different, so it's pretty hard to recommend any particular setup.... This chart for a Ninja regulator may help....

Image

The basic Belleville stack was ten 0.032" thick Bellevilles in series.... ) () () () () ( …. The black line labelled "2 Thick Cup Washers" was twelve 0.032", like this.... )) () () () () (( …. The "Thin Cup Washers" were 0.022" ones on the ends, instead of the 0.032" paired ones....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Wed Jul 18, 2018 7:58 pm 
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Joined: Tue Sep 22, 2009 9:57 pm
Posts: 64
Location: Aurora, ON, L4G7X4
Thanks Bob, the graph and the washer thicknesses makes sense to me.
I have couple regulators new or used in my drawers but by coincidence I have only two the same built 1800 psi these I would like to rebuild.
I have one of each 3000psi 48cu tanks, Ninja and PureEnergy, my plan is to pair these to be the same output pressure so I don't need to run always to the scuba store for refill. .
Ordering some belleville washers tonight.

Edit:
Can you explain me what is a difference between stacking washers like these:
- )()()(((())) ......................................these currently I have them in 1800 psi regulator 0.035 thick , would be nice if I can remove or rearange some to get lower to a 1200-1300 ballpark.
what is a difference between "nested stack" (like the right seven washers) and "inverted stack" (the left five washers)?


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PostPosted: Wed Jul 18, 2018 8:52 pm 
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Joined: Sat Nov 03, 2007 4:19 pm
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Location: Coalmont BC
This part pf the stack.... (((())) …. is 3 to 4 times stiffer than a single Belleville.... so basically it doesn't move, and all the work is being done by the )()() portion.... Worse than that, where the single Belleville is stacked against the quadruple set, it is prone to damage because it can get reversed (pushed past flat)…. Basically that is a horrible arrangement of Bellevilles…. I always use Bellevilles singly, in series.... )()()()()()( …. or in pairs )) (( )) (( )) (( to avoid damaging them.... The paired (nested) arrangement is twice as stiff, but only has half the travel of the series (inverted) stack....

I prefer the series, single stack (inverted) provided the Bellevilles are stiff enough to provide the pressure you want.... because they then have the most travel, and the regulator will open further and refill faster.... I only use the paired arrangement if I need more pressure....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Wed Jul 18, 2018 9:17 pm 
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Joined: Tue Sep 22, 2009 9:57 pm
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Location: Aurora, ON, L4G7X4
Theoretically is it possible to rearrange the existing 0.035 thick washers 12 pieces )()()(((())) to a 10 or 8 pieces )()()()()()( can I get to a range below 1500 psi given that the washers are 0.035?


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PostPosted: Wed Jul 18, 2018 10:37 pm 
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Joined: Sat Nov 03, 2007 4:19 pm
Posts: 8936
Location: Coalmont BC
It depends on the exact regulator.... but I am pretty sure you can hit your goal with 12 x 0.035" arranged either as you suggest.... or if that stack is too long, then like this....

)) () () () () ((

with possibly some flat shims on one end.... That should be close to the black line on my chart....

If that is too long, then 10 x 0.035" in series....

) () () () () (

with some shims....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Thu Jul 19, 2018 7:45 pm 
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Joined: Tue Sep 22, 2009 9:57 pm
Posts: 64
Location: Aurora, ON, L4G7X4
Thanks,
I would like to try to modify with existing 0.035 washers before online ordering belleville washers, I can try both of your sketches and which works best I will just adjust the second.


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