{"product_id":"0-275in-buna-n-o-ring-cord-stock-70a-durable-seal-replacement","title":"0.275in Buna-N O-Ring Cord Stock 70A - Durable Seal Replacement","description":"\u003cp\u003eIn this review of the 0.275in Buna-N O-Ring Cord Stock the bottom line is straightforward: this cord is for anyone needing a durable, petroleum-resistant round o-ring stock for custom seals and repairs. The reviewer found it particularly useful for replacing small rubber tires and for forming glued o-rings, with the single biggest reason to buy being its balanced \u003cstrong\u003e70A durometer\u003c\/strong\u003e that offers flexibility without sacrificing wear resistance. It ships as a 25ft piece and is made in the U. S. A., making it easy to cut, glue, and shape for workshop and field seal work.\u003c\/p\u003e\u003ch2\u003eKey Features\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Buna-N (nitrile) formulation gives broad compatibility with petroleum products and many hydraulic fluids, reducing swelling and failure in hydrocarbon environments.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHardness:\u003c\/strong\u003e 70A durometer offers a firm but flexible feel that holds shape well for o-ring fabrication and provides reliable compression set resistance.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTemperature range:\u003c\/strong\u003e Rated to handle typical operating temperatures, making it suitable for many industrial and automotive tasks without immediate hardening or softening.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLength and size:\u003c\/strong\u003e Supplied as a 25ft piece of 0.275in round cross-section, giving ample material for multiple custom o-rings or repairs.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDurability:\u003c\/strong\u003e Buna-N resists abrasion and tear in many sealing applications, which customers reported as translating to long service life under normal use.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eWho It's For\u003c\/h2\u003e\u003cp\u003eThe cord is best for hobbyists, mechanics, and maintenance technicians who need a dependable, easily glued round stock to create replacement o-rings, small tires, or custom seals for petroleum-based systems. Its compatibility with oils, HFA\/HFB\/HFC fluids, and vegetable oils makes it a practical choice for workshop repairs and moderate industrial use.\u003c\/p\u003e\u003cp\u003eIt is less suitable for applications exposed to ozone, strong solvents such as acetone, or direct UV light, and those needing extreme low-temperature flexibility beyond the stated range should look to specialized elastomers instead.\u003c\/p\u003e\u003ch2\u003ePros \u0026amp; Cons\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003ePros\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eGood chemical compatibility with petroleum and many hydraulic fluids for dependable sealing.\u003c\/li\u003e\n\u003cli\u003e70A hardness balances flexibility and wear resistance for long-lasting custom o-rings.\u003c\/li\u003e\n\u003cli\u003eGenerous 25ft length and consistent 0.275in size make it economical for multiple projects.\u003c\/li\u003e\n\u003cli\u003eMade in the U. S. A., with customers praising fit, adhesive ease, and durability.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eCons\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eVulnerable to acetone, ethers, esters and ozone, so it should not be used where those exposures occur.\u003c\/li\u003e\n\u003cli\u003eTemperature limits and weathering concerns mean it is not ideal for prolonged UV or outdoor exposure.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eSpecifications\u003c\/h2\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaterial\u003c\/td\u003e\n\u003ctd\u003eBuna-N (Nitrile, NBR)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCross section\u003c\/td\u003e\n\u003ctd\u003eRound, 0.275in (nominal 1\/4in, 7 mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDurometer\u003c\/td\u003e\n\u003ctd\u003e70A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLength\u003c\/td\u003e\n\u003ctd\u003e25 ft piece\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eColor\u003c\/td\u003e\n\u003ctd\u003eBlack\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTemperature range\u003c\/td\u003e\n\u003ctd\u003eApprox -40 F to 212 F (-40 C to 100 C)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOrigin\u003c\/td\u003e\n\u003ctd\u003eMade in the U. S. A.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003ch2\u003eOur Verdict\u003c\/h2\u003e\u003cp\u003eThe 0.275in Buna-N O-Ring Cord Stock is a practical, cost-effective choice for anyone needing a robust, petroleum-resistant round stock to make or repair o-rings. With its \u003cstrong\u003e70A durometer\u003c\/strong\u003e, long 25ft length, and good adhesive properties, it delivers solid value for workshop and maintenance use, provided the user avoids solvents, ozone, and prolonged UV exposure.\u003c\/p\u003e\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eCan this cord be glued into custom o-rings?\u003c\/strong\u003e\u003cbr\u003eYes, customers reported it is easy to glue and form into o-rings using compatible adhesives for Buna-N.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs it safe for use with hydraulic fluids?\u003c\/strong\u003e\u003cbr\u003eYes, it is compatible with petroleum, HFA, HFB, and HFC fluids as stated, making it suitable for many hydraulic applications.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill it handle outdoor UV exposure?\u003c\/strong\u003e\u003cbr\u003eNo, Buna-N is vulnerable to ozone, sunlight, and weathering and should not be used for prolonged outdoor UV exposure.\u003c\/p\u003e","brand":"Mr O-Ring","offers":[{"title":"Default Title","offer_id":48245910438107,"sku":"B00QVB56CY","price":39.59,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0724\/1043\/1707\/files\/712mL2CVl4L._SL1500_88162347-564f-4a86-aaea-284f34c8d597.jpg?v=1770925728","url":"https:\/\/gearmusthave.com\/products\/0-275in-buna-n-o-ring-cord-stock-70a-durable-seal-replacement","provider":"GearMustHave","version":"1.0","type":"link"}