FT Piston seal life.

[Cross Pistol Packer]

Thanks from me as well Gents,good info indeed
Ray...

[DRAGON64]

Interesting that more than one user has a problem with the seals on these flat top pistons... could be this be a problem across the board with other FT makers?  I am about to pull the trigger on some mod orders, and I keep finding road blocks such as these.

[eric]

i would say no. all seals will wear ,some quicker than others.roy from mountainair has been doing this for a while and i havent' hear anything about his pistons and gil is back making some and if you haven't seen his stuff ,it's top notch fer shur

[packrat]

  Don't try to use that as an excuse to NOT BUY MORE STUFF    Like the man said--all seals wear out..you justt happen to hear about more than one here.......happens everyday to folks all over the world..just VERY seldom that ya hear about 'em..might be caused by improper installation, or not replacing with new, or it just got old and worn out!! Don't let that stop ya from getting on with the projetct that you KNOW you GOT to have 

[1377x]

it's the same with the stock pump cup they go,too
the only way to avoid it is to not use it and i for 1 have trouble putting mine down

[1377x]

i found a pic of the white seal for the 130 piston

and here's the clear it fits the piston better

[Cross Pistol Packer]

Good pics Noob,let us know how they perform compared to o-rings for longevity.
Run my vernier over a new seal that came with the AC piston. ID 9.0 mm seal thickness 1.75mm(012 in o ring sizes)
going to buy several seals in different materials and evaluate them in use.
found some standard o-rings at work, NBR 70 shore,quite soft I think,will see how long they last for starters.

[1377x]

will do!
hopefully an o-ring that lasts can be found

[arkmaker †]

I'm not sure what material it was, but I had tried a Yellow one I got from work and it was a waste of time. It only lasted about 50 pumps and was leaking llike a hole in the hoover dam! I noticed that it was much softer than the ones I got at Ace (black). Don;t know what they are, but will ask next ime I go in there. No probllems with them at all.
Rich

[1377x]

in my experience i think im a good part of the problem letting the gun heat up during pumping

[zoned]

I think 90 durometer urethane may work well, Tim at Mac1 Airguns uses these for just about every kind of seal he puts in a gun. Those combined with some of his "Secret Sauce" should last for a long long time I would think.

[Cross Pistol Packer]

Trying to lay my hands on some Kalrez o-rings,they can take up to 327 degC and take a lot of stress.

[Cross Pistol Packer]

Just tried the standard NBR 70 shore seals,42 pumps (3 at 10,one at 12)seal shot...
Worth a try.
Back to using the 90 shore seals that AC supplied with there piston.
As soon as I can get the Kalrez seals,will fit one to my spare piston.
Ray...

[Cross Pistol Packer]

Fitted a Kalrez seal last night as the 90 durameter seal was shot,seems to pump ok but not so hard to pump,FPS was down more than 100fps,it was worth a try.
Have taken a look on ACs site,is the seal on there FTP  been improved with larger more beefy seal ?
May well try one of Gmacs FTP in the 1389.

[1377x]

follow-up from nov.'10
i ended up selling the piston with the clear cup to a member here so i dont know how that one is holding up
still using the piston with the white cup,still no issues.through the winter it was used everyday by multiple people for fun and pest control.at least 300 pumps a day,since the spring/summer time it hasnt been used to much a little pest control,some testing and sight in.still no issues
i like the set up its the only piston type i use now .it gets the same numbers as a flat top piston,lasts longer than o-rings and at a fraction of the cost
i think i paid $8-$10 and a new cup runs @$3-$5 installed
i do keep my guns/pistons well oiled.i should say airguns well oiled