Valve seal material?

[TerryM]

  I need to know what specific material I should use to make seals for old pumpers.  I am off work today and aim to go to a local shop that specializes in gaskets and seals.

[TooJung2Die]

  I need to know what specific material I should use to make seals for old pumpers.  I am off work today and aim to go to a local shop that specializes in gaskets and seals.

I'd go with neoprene rubber. Oil resistant, durable, it's what most o-rings are made of. It's what most seals that weren't leather were made from.

[TerryM]

  Went by the aforementioned shop and picked up three scraps of neoprene: 1/8", 1/16" and 1/32" thick, 60 durometer.  I think I am equipped now to reseal my Apache, if I ever get the valve out.

[45flint]

  Went by the aforementioned shop and picked up three scraps of neoprene: 1/8", 1/16" and 1/32" thick, 60 durometer.  I think I am equipped now to reseal my Apache, if I ever get the valve out.

Everyone is rooting for you!  That model always fascinated me not I’m just not as brave as you.  And if you succeed I still won’t be as brave!

[TerryM]

  Thanks Steve.  Not bravery, just determination.  I only have 75 bucks in this thing.  If I can make it shoot, cool.  If not, oh well.

[Back_Roads]

 Way back in the day I had great success making my own leather seals for my  now rare Daisy springer. I was only 14 at the time and main reason the gun is rare is I lost it about 10 years ago and sold the property and house I hid it on 
 OK n/m

[ped]

60 shore might be a bit soft I use 80 shore urephane to reseal the old crosman valves
I tried rubber sheet in both nitrile end epdm but it was a bit soft I'm also trying a vinyl used in fork truck access ways
I make my own punch's and inserts to suit the seal I'm making as often std punch's are either too big or too small

[AirPower]

Ped,

 That top picture of yours caught my eye as it is real similar to what I am attempting to do on an old S&W 77A. Was the brass on that valve seal rolled over to hold the seal in place?

 Is that red material the Urephane you referred to? I never heard of that material before....did you mean Urethane? I know that Urethane comes in all sorts of different colors but I  am unsure what material would best work on a valve like that.

 Today I just finished digging out whatever the stock material was they used in this intake valve. It was a weird gray colored material with little white fibers in it. Could not tell it had those fibers and it looked black to the naked eye but with an Optivisor I could get a much better idea of what it was made up of, but still do not know what that material was. It was REAL hard to dig out, a tough old seal whatever it was, and I did end up scratching the heck out of the brass cup that houses the seal so had to re-machine the inside as well as the bottom face. Like you I will probably have to machine or make some  little cookie cutter type seal cutters, once I settle on a material to try.

 I got a piece of Urethane from a local gasket and seal place here but am wondering if it is to hard to use in that application because it just does not seem like it would seal. Course maybe with a couple springs pushing on it, it will?

 This material is a little thick too but if it sits a little proud of the pocket it fits in, it may make it easier to remove next time it gets changed out?

 

[Rob112o]

Material look like the last couple pics in this album?
Scott informed me that's good ole asbestos!!

[TooJung2Die]

The inlet valve seals you get from MAC1 for Sheridan are a very hard white material. I believe it is PTFE. Different airgun valve but the same purpose. It is so hard that Tim's instructions tell you to place the inlet seal on the inlet valve seat and whack it good with a hammer and drift so the valve seal gets dented by the valve seat. Use the hard urethane seal material you have. You may want to try the MAC1 "whack a seal" procedure on it.

[ped]

David no the seal is held in place by the stem collar
on my seal refurb I mill the brass a bit deeper to allow for the thicker seal material which is urethane my spelling was having a bad day when I posted

[AirPower]

Rob112o: No the material does not look like that at all, it is a really dark grey, almost black as I mentioned. It looks black till I get it under a bright light AND have an Optivisor or a good eye loop on. The fibers are really tiny and there again cannot even see them till magnified. Not sure why they would use asbestos in there as I do not think it would ever see that much heat, would it? Maybe if you were pumping it up time after time like a madman (you know like you were REALLY trying to put a critter down, or something like that?) THEN maybe it would need asbestos in that seal area. Could be though. I have dealt with ALL sorts of oddities and different materials over the years but never seen one quite like this. It sort of reminds me of the old packing type seals used on way old sink faucets but a LOT tougher.

TooJung2Die: I could believe that as Teflon is real dense (like me!) and does not take a set to easily. Doing that I imagine would tend to smash that seat into the Teflon better and give a wider, deeper area to help it seal up. I got plenty of Teflon and after messing with this Urethane today it would be WAY easier working with than that Urethane. I was trying to cut it on a lathe and man it moves all over the place. WAY worse than rubber. Even tried freezing it... a trick you can use and get real good results with in most all rubbers after you play with it some, but that is no dice in this Urethane. I can believe this stuff WOULD work GREAT if I can get a seal made the right size.

ped: I THOUGHT that may have been a typo.... I even went and asked the goog if there was such a material as that as even after all the time I been messing with different things I STILL run into new or little used and unheard of materials from time to time. In fact I just ran into a new one the other day while researching a Moore jig bore machines clutch plates...Twaron...I guess it is real similar to Kevlar....but first time I ever heard of it. I can relate to typos also though as some days my fingers become disconnected from my brain!

 Looking at the steel stem collar on this old S&W intake valve seal it has sort of bulbous shape to it and that will certainly help hold the seal back against the back seat portion as well as make it pert near impossible to get a good measurement for the seal, but then they also rolled over the brass on the outside front lip. Did this same thing on the intake valve lip as well. I thought if I just machined that rolled over lip off the seals would come right out....NOT!

Last night I had another thought I WISH I would have had before I went and scratched up that intake seal yesterday. I took and machined off that rolled lip on the exhaust valve seat as I did on the intake yesterday. It took about .015 to relieve that, and then I took off about another .010 of the brass that captivates the seal as well as that front face of the seal. That cleaned up and got rid of the part of the seat that has been compressed all these years and got me down to some better rubber. I can tell by pushing on the seat with an itty bitty allen wrench that I am back to some rubber that has some life left in it so may just try putting that one back in to see. Course I STILL need to make a seal for the Intake side but COULD have addressed that seal the same way I bet. To late for that now though.

 Fortunately I made a little drawing of each of these valve seats so if I HAVE to I can build whole new ones...but If I do that they WILL get changed some for better, simpler, and easier seat changes.

 Will sleep on it and see what other options I can come up with too.

 Thanks for the replies guys!

[ped]

funny you should mention about re facing the seal I do this on the 2240 and similar constructed stems
I tried to fit new seals to them and gave up as not worth the hassle for the cost of a new stem but on one I took a couple of thou of and it cleaned up nicely
when I took my 78 apart all seals were good so I unplugged the barrel of 5 stuck pellets and re built it without re sealing it
I do have an issue with the probe seal and I'm not sure if barrel has been replaced and the leade taper has been cut over size as an o ring that seals it hangs up on the loading trough ,one that clears the trough nicely suffers blow by

[AirPower]

Yeah, if I could buy new stems for this one I would, but since these have been out of production for a couple/three/four decades it is not an option.

 I used a tool steel blank ground to a real sharp point and then just barely knocked the edges off of it to try and get a real small radius on the cutting edge. It has a pretty good chip breaker ground into it as well as I use this tool  in aluminum quite a bit. It did a great job of refacing that existing seal.

 I been searching around on the web quite a bit too (till my eyes about bugged out!) and did find a couple places that make square cross sectioned small o-rings in a couple different materials as well. Buna, Viton, and even had some cast polyurethane ones but only in round cross sections on those. They were just about the perfect size though so have a couple coming to check them out! Could I BE so lucky? Will see. probably have a better chance at winning the lottery...well.... IF i would go buy a ticket!

 You probably already checked this but on your loading trough look at it real close with an eye loop or Optivisor as I worked on one for a buddy that had a really tiny ding that would catch the seal. Could not even see it till magnified. Not even sure how he could dent it like that down in the bottom of that area, but things do happen. I took a really miniature "bendable" file I got years ago and was able to clean it up nicely once I got the proper angle to attack it with the file.