Ques. about O-Ring hardness & material for WEIHRAUCH HW100

[airsand]

I have the HW100 and am looking to order some spare O-rings for it. Based on a previous post I found on here I have the dimensions for all of the HW100 O-rings.
So now I am just looking to find out what material is recommended to order these O-rings in: Buna, EPDM, Viton?

Also are all the O-rings for the HW100 the same hardness (durometer)??

Any guidance would be appreciated.


-Jack

 

[MikeVV]

There's even a teflon ring or two.
I just bought a hand full of kits, so I will be prepared..! Should be here (SoCal) later this week.

Here ya go -

Weihrauch HW100 and HW101 - Bagnall and Kirkwood Airgun Spares

Please find below the exploded parts diagram, parts list and available spare parts for the Weihrauch or HW100 and HW101 air rifle (including all models such as HW100 K KT S BP/Bullpup etc.). For any spare parts not listed for the HW 100 and 101 airguns please feel free to contact us. Exploded...

spares.bagnallandkirkwood.co.uk

Mike

 

[airsand]

There's even a teflon ring or two.
I just bought a hand full of kits, so I will be prepared..! Should be here (SoCal) later this week.

Here ya go -

Weihrauch HW100 and HW101 - Bagnall and Kirkwood Airgun Spares

Please find below the exploded parts diagram, parts list and available spare parts for the Weihrauch or HW100 and HW101 air rifle (including all models such as HW100 K KT S BP/Bullpup etc.). For any spare parts not listed for the HW 100 and 101 airguns please feel free to contact us. Exploded...

spares.bagnallandkirkwood.co.uk

Mike

Hi I can purchase these locally, there's an O-ring company nearby... I just want to know the O-ring material and hardness (Durometer) that is recommended for the HW100... Hopefully someone knows that specification...

 

[MikeVV]

Well...as I mentioned...one or two in the newer kits are Teflon !! You won't find those at Lowes !
Sorry to have bothered you.

Mike

 

[airsand]

Well...as I mentioned...one or two in the newer kits are Teflon !! You won't find those at Lowes !
Sorry to have bothered you.

Mike

From my understand Teflon is a PFAS forever chemical and 3M is in the process of having it being discontinued very soon. Does anyone know if Buna material is recommend for air gun O-rings? I hear Viton is also well regarded too.

There is an O-ring manufacturer nearby, they can get me any type of O-ring... BTW There is a nationwide postal strike happening in the UK currently so I would like to purchase them local. Thanks

 

[aussiegav]

I always used Duro 70 it is a easy gun to work on 90% of the time you only need to change 3 orings the small 005 on and in the main valve and the oring that leaks the most is a 14X1 that sits under the valve. It takes a long time to before you need to change the teflon oring.

 

[Feinwerk]

Hello @airsand , A standard choice for all around air rifle and PCP o-ring material is Buna N rubber in 70 durometer. Sometimes people experiment with other materials for higher wear applications with more sliding abrasion like breech O-rings rubbed by a bolt probe. I have seen polyurethane recommended for this but I myself have not tried it and cannot vouch for its performance in this application.

Mike reported that some of rings in his kit were Teflon. Perhaps either the factory or someone in aftermarket has determined that this is better but he didn't say where the Teflon rings go. Others with this rifle could advise

The standard Buna n 70 is very economical and appropriate. Be sure to pick up some silicone grease for O-ring replacement inside your PCP. It helps prevent the O-ring from getting cut during assembly and helps make it seal better. Divers Grease, automotive spark plug dielectric boot grease, or Moly coat 111 are all examples that can work. Even Danco waterproof grease in the plumbing section at the home store is a silicone grease that can work just fine.

I don't use silicone grease on my breech O-rings since I lube my pellets. The lube on the pellets transfers to the breech O-ring and bolt surface all by itself.

Feinwerk

 

[airsand]

Yes it seems Buna 70 is the default unless otherwise stated. Understood now.

thank you!

 

[Vana2]

airsand,

I recently resealed my .22 HW100S FSB using the HW100 Tuning kit and following along with these two videos from the Sub 12 Airgunners channel.

Everything is clearly explained and the reseal job was quick and easy to do.

I tried to source the o-rings locally and ran into minimum quantity, minimum order and would only sell to businesses problems. I finally said to heck with it and bought the kit. Figured that it was a lot cheaper and less hassle in the long run. If you do buy locally, you may want to make up some kits to get rid of the extra o-rings

Enjoy your HW100!

 

[Feinwerk]

From the second video above it looks like the valve stem o-ring is Teflon. You can see the white O-ring that gets put on to the stem on the left side of the valve. Here's a screenshot I took from the video. If this is indeed the factory condition, then it has been determined that Teflon is best for this particular part and application. Kind of makes sense as the valve stem moves and rubs with each shot and reducing friction here would help shot consistency.