Kirk, considering Huma makes quite a few different regulator sizes, you may need different O-rings. If you need help identifying the proper sizes, measure the groove diameter and OD with calipers and report back.
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Tuning Regulators and O-ring longevity
- Thread starter nervoustrig
- Start date
Just my thought on this Air has oxygen and co2 both oxidizers that are in constant contact with o-rings I only use nitrogen so NO Oxidizers
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Don’t know if this is helpful or not, but may be food for thought. Yesterday I met with someone who had a bushbuck 45 and an airforce texan for sale. I ended up buying both. Both these guns had set without air in them for about 2 years or so. When I tried to air them up they both leaked rapidly out of the fill port. Inspection showed that both the fill port valve orings were completely deteriorated. Upon replacement of these two orings, they both hold air so all the other orings are still good.
So in this case the orings that were exposed to light and air exchanges failed. I assumed that exposure to light/uv and ozone in the air and the degradation of plasticizers were to blame.
So in this case the orings that were exposed to light and air exchanges failed. I assumed that exposure to light/uv and ozone in the air and the degradation of plasticizers were to blame.
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Hi Kirk, yes those are the inside dimensions (industry standard way of calling out metric O-rings). But again, Huma makes a bunch of different regulator configurations...I think the piston and adjuster is the same across them but Mike cautioned that the body ODs are all over the place so put a caliper on yours and report back if you need help confirming the correct size.
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Viton 90 durometer seems to be the best choice, its available in any size from tehse guys.
https://www.canyoncomponents.com/fkm-viton-fluorocarbon-o-rings-gaskets
They also have a very handy sizing chart, I printed and hanging on the wall.
https://www.canyoncomponents.com/as568-sizing-chart
https://www.canyoncomponents.com/fkm-viton-fluorocarbon-o-rings-gaskets
They also have a very handy sizing chart, I printed and hanging on the wall.
https://www.canyoncomponents.com/as568-sizing-chart
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Yes I think 90 durometer Viton is a perfectly good choice so long as you can get it installed without tearing it. A small diameter O-ring (like the HP end of a regulator piston) sees a lot of stress during installation, and my experience has been that Viton is more apt to tear than Buna-N. An approach that helps is to drop the O-ring into a cup of hot water first, and then work quickly to get it installed.
For regs working at fill pressures up to 250 bar (3600psi), the more common 70 or 75 durometer should be more than sufficient to resist extrusion failure. Abrasion resistance doesn't seem to be much of a consideration in this application.
For regs working at fill pressures up to 250 bar (3600psi), the more common 70 or 75 durometer should be more than sufficient to resist extrusion failure. Abrasion resistance doesn't seem to be much of a consideration in this application.
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