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Thread: Delrin vs PTFE for poppet cupseal material

  1. #1

    Delrin vs PTFE for poppet cupseal material

    I bought a Delrin rod to make some new G6R poppet cupseals out of but I noticed that the material looks different than the stock cupseal material. I thought the stock material was Delrin but it seems like it could be PTFE.

    Is there any real difference between the two when using them for face seals? I've looked up the material properties for both and it looks like Delrin is actually both stronger in tension and softer, so it seems like it be a better seal material, but I'm no material scientist.

  2. #2
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    I thought most poppets were nylon?

  3. #3
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    All 3 have been used in oem applications.

    90a polyurethane is a candidate as well, I think the old black magic cupseal may have been cast pu.

  4. #4
    Cool, thanks guys.

    irony, this poppet could be nylon. I cut a small shaving off and it's slightly translucent.

  5. #5
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    I think PE and axe poppets are nylon. I can't tell on BL, but I think those are teflon or delrin. I know a guy made some delrin donuts that work well, so I lean towards that being the OEM material.

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    The old cocker exhaust valves that the all-black valve head were molded PU, correct.

    We use acetal homopolymer/Delrin on the Ego/LV exhaust valves and guides and POM for Etek.

    You have to be careful of porosity in any bar extrusion you use. You can end up chasing leaks forever.

    PTFE isn't so good in my experience.
    Dear boy, I work at Planet Eclipse, don't you know..

  7. #7
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    Whelp, the best engineer in paintball at durability assessments weighed in... Emulation is the greatest form of flattery. I'd pick one of the 2 he uses and never think twice about it.

    Jack, if you don't mind, do you use the same material for reg seats? I don't understand what some people are using, but they get chewed up so fast when I went years without a single issue on my PE regs. The longer I play, the more I appreciate the PE design philosophy of reliability first.

  8. #8
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    We use 90 Shore PU for reg seals.

    Having a softer material looses you some in outright performance terms, but more than pays back in longevity and reliability in a reg seal.

    On the exhaust valve, if you are going to use POM/Delrin they need to be impeccably machined. They will only tolerate the smallest of imperfections/scratches on the sealing faces. But you get a really clean lift out of them in a simple two-piece construstion (steel stem and solid delrin/POM head).
    Dear boy, I work at Planet Eclipse, don't you know..

  9. #9
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    Thanks. I'm not sure what the axe uses on the poppet, but I still think it may be nylon. Also, it's interesting that your reg seats are only 90 duro. That is softer than I'd have expected, but your logic makes sense. Not sure why, but on M2s they got a bad batch of LPR seats that were apparently softer and it had a significant effect on performance.

  10. #10
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    It will do on an LPR. Normally the post-regulated reservoir isn't large enough to complete a drive in a single direction. Especially on something like an M2. So the reg has to kick in to complete the forward (and reverse) cycle. If the seal is too soft it could potentially cause an issue where the reg isn't kicking in fast enough or flowing enough and then it starts to affect the cycle.

    What were the symptoms of the bad seals?
    Dear boy, I work at Planet Eclipse, don't you know..

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