Replacement O-rings for bison tubes

[+Forest-Ghost]

Hello, I am looking to get some replacement O-rings for bison tubes. I found this post a while back but can't seem to find the right sizes on amazon. I am looking to get o rings for both the thinner bison tubes and the thicker "scuba" bison tubes. Does anyone know what sizes to order and also recommendations on brands? Most of the listings are not in metric and the conversions from US customary units are not precise. Ideally, if you could provide a link, this would be very helpful. Also, I'd like to avoid order replacement o-rings from geocaching stores since they tend to be heavily marked up. Thanks!

[+MtnGoat50]

I get my O-rings from The O-Ring Store in Clarkston, Washington. The 2mm X 11mm E70 EPDM 70 Duro Metric O-Rings cost 10 cents each (20 qty. minimum). Their minimum order is $5 and you get free shipping at $10. They have pretty much any size and any material you want. Someone recommended EDPM to me for outdoor use so that's what I bought. I bought a variety of sizes for bison, scuba bison and Mega bison. 

[+Wadcutter]

Any hardware store will have an assortment.  They may have a specialty section.  If not look in the plumbing section for parts to repair leaky faucets.  I've gotten some there.

[+Forest-Ghost]

Thank you so much, I will check out both of these options.

[+Forest-Ghost]

2 hours ago, MtnGoat50 said:

I get my O-rings from The O-Ring Store in Clarkston, Washington. The 2mm X 11mm E70 EPDM 70 Duro Metric O-Rings cost 10 cents each (20 qty. minimum). Their minimum order is $5 and you get free shipping at $10. They have pretty much any size and any material you want. Someone recommended EDPM to me for outdoor use so that's what I bought. I bought a variety of sizes for bison, scuba bison and Mega bison. 

 

What size do you get for scuba bison?

[+MtnGoat50]

Just now, Forest-Ghost said:

What size do you get for scuba bison?

It took some searching but these are the sizes I bought based a recommendation from another cacher back in 2016.

2” (standard) bison: E70012-PC, 012 EPDM peroxide cured 0.364” ID x 0.07” CS   (minimum order (25 qty.) costs $3 (12 cents each). I think I got 50 and a selection of the other sizes to meet the $9.95 free shipping.) 

2.5” bison: E70014-NSF, 014 EPDM peroxide cured 0.489” ID x 0.07” CS

Megas: E70135-NSF, 135 EPDM peroxide cured, 1.925” ID x 0.103” CS

SCUBA: E70016-PC, 016 EPDM peroxide cured, 0.0618" ID x 0.07" CS

 

You can save some money by skipping the peroxided cured option but my understanding is they hold up better and last longer.

 

2 hours ago, Wadcutter said:

Any hardware store will have an assortment. 

I'm not saying you're wrong and I'm sure it varies from region to region but my experience in my area is that the hardware store has a poor selection in geocaching sizes. That and paying $1 for a single (close to) bison sized o-ring made me look elsewhere.

 

[+Forest-Ghost]

Thank you so much! I really appreciate you sharing all this info. Now I can finally get some o ring replacements. 

[+colleda]

Tried Harbor Freight?

https://www.harborfreight.com/397-piece-metric-o-ring-assortment-67580.html

I get the same thing here from Aldi. Lots of rings, different sizes. I also find them handy for other things besides geocaching bison tubes. e.g garden hose connectors.

 

Edited September 23, 2023 by colleda
added info

[+Wadcutter]

12 hours ago, MtnGoat50 said:

I'm not saying you're wrong and I'm sure it varies from region to region but my experience in my area is that the hardware store has a poor selection in geocaching sizes. That and paying $1 for a single (close to) bison sized o-ring made me look elsewhere.

 

Oh please.  Regional?  Faucet repair kits aren't sold by regions.  A Moen faucet is going to be the same faucet in Spokane as any where in the US.  Same with all the other makers of plumbing fixtures.  Spokane isn't "special".  

You need to check other hardware stores.  If your hardware stores do not have a plumbing section with faucet repair kits then you don't have a hardware store.  The O ring for a bison tube is not a special O ring made just for bison tubes.  They're a common size.  You just have to look or ask if you aren't able to find them.  

Edited September 22, 2023 by Wadcutter

[+chuck4564]

The Nitrile rubber material found in the Harbor Freight package suggested by colleda isn't the best material selection for an application that is likely to include UV exposure. The EPDM material suggested by other posters is a better selection.

 

o-ring material quick reference

o-ring material guide

 

 

[+cerberus1]

Pretty much every hardware or auto parts store have cabinets of O-rings.  

We have an assortment of bisons, and all take a different size ring (and matchstick holders use washers...). 

The last batch we bought years ago online were the right size, but too thick to secure the two pieces. 

So maybe it's just me, but a simple stop in the store when passing by is worth it to be sure it's the correct size I need...

 

Edited September 22, 2023 by cerberus1
spellcheckquitspellcheckquit

[+Viajero Perdido]

AliExpress sells assortment packs in nice organized container boxes for next to nothing.  I bought a 200-pack for a few dollars and threw it in the pack.

 

https://www.aliexpress.com/w/wholesale-o%252drings.html?catId=0&SearchText=o-rings

 

Edited September 22, 2023 by Viajero Perdido
Getting the link right

[+colleda]

11 hours ago, chuck4564 said:

The Nitrile rubber material found in the Harbor Freight package suggested by colleda isn't the best material selection for an application that is likely to include UV exposure. The EPDM material suggested by other posters is a better selection.

 

o-ring material quick reference

o-ring material guide

 

 

I use a lanolin based spray (Lanotec)  to treat O rings. It helps them last much much longer and adds a little waterproofing effect too.

[+GrateBear]

Prtobably Ace Hardware if you have one nearby.  They seem to have everything (except lumber).

[+Mockingbird559]

Amazon has lots of o-rings, just get the right size and material. These are the measurements I use

 

Regular Bisons 3/8" Inside diameter, 1/2" Outside diameter, 1/16" thickness

Nano's 5/16 Inside diameter, 7/16" outside diameter, 1/16" thickness

Matchstick tubes:15/16 Inside diameter, 1 1/16" outside diameter, 1/16" thickness.

BIG Bisons 1 7/8" Inside diameter, 2 1/8" Outside diameter, 1/8" thickness

 

Sample part number for nanos AS 568 011 on Amazon. (Just a starting point)

 

I like the silicone red, the black neoprene doesnt hold up.

 

these are low enough in cost to give away on the hunt as repairs

[+kunarion]

1 hour ago, Mockingbird559 said:

Matchstick tubes:15/16 Inside diameter, 1 1/16" outside diameter, 1/16" thickness.

 

Are those flat washers as they come from the factory?  Not round cross-section O-rings, rectangular.  I've noticed that the cap design on at least some of my match tubes requires flat washers.  But the diameter is somewhat different on tubes from various manufacturers. 

 

Same with bison tubes, some O-rings must be stretched to fit.  And nanos especially, they all seem a little different.  It's never quite right, and the log sheet is soaking wet even when I thought everything was perfect.  The O-ring seems more like a temporary decoration than a practical device.

 

Is there a fool-proof measurement technique that you use?  I've gone in person to Ace Hardware to get just the right size for a fake sprinkler head (for example), and there are some too small (must stretch), some loose, some too thick where you tighten the cap and the O-ring pops to the outside of the cap.

 

I hope to find a durable decorative O-ring.  Yeah, maybe silicone rubber.  Finders over-tighten, break and lose these O-rings and don't mention an issue.  If it at least lasts a few finds, it's good.

 

Edited October 11, 2023 by kunarion