My Foster “style” coupling (had) two O-rings inside the inner base of it. They disintegrated so can anyone tell me what size they are?
What size O-ring for Foster coupling?
- Thread starter igolfat8
- Start date
If you mean the size in the spring-loaded collar of a female Foster, yes it’s a -010 as Centercut said. If it’s a seal for the threaded connection into the equipment, I don’t think there is a standard that applies everywhere.
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Would this be it?
Buna Orings # 010-70D FDA/NSF61 Minimum 100 pcs
Buna O-rings Size #10= 1/4 ID x 3/8 OD x 1/16 CS Our Buna Nitrile rubber
Buna Orings # 010-70D FDA/NSF61 Minimum 100 pcs
Buna O-rings Size #10= 1/4 ID x 3/8 OD x 1/16 CS Our Buna Nitrile rubber
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I had a female Foster start leaking and discovered a bad o-ring inside. I bought these off Amazon and all is well, now.
https://www.amazon.com/gp/product/B01BO0WPE8/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1#customerReviews
https://www.amazon.com/gp/product/B01BO0WPE8/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1#customerReviews
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If your fitting uses two O-rings it is most likely to be one of the brass QDs that come with the Chinese filters and compressors. The size is 4mm ID x 2.5mm section giving an OD of 9mm. There is no standard size, even for the single ring brands. The size that gets quoted a lot in forums is probably for the original Foster-made product. There are a lot of copies around now and many of them use different size O-rings. I hope that this may explain the confusion.
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Yes the one in question is a brass (likely) Chinese made female coupling. The size you quoted seems more in line with the bore size that I measured on this coupling. Also this one does not have a recessed inner grove for the O-ring to fit into. The bore is straight walled. Thanks EagleBeak.
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yeah a lot of the chinese ones use 2 and they get mangled easily.
grease them with silicone grease or a couple drops of silicone oil so they sit properly and move with the air to fit tight and not kink under pressure.
grease them with silicone grease or a couple drops of silicone oil so they sit properly and move with the air to fit tight and not kink under pressure.
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