Articles

Short, practical tips on selecting and installing O-Rings.

Large black vulcanized O-Ring on an Olypsys Large Format Grid, measured with a phone for ID and cross-section verification

Precision Vulcanized O-Rings: Tolerances, Olypsys® Inspection, and why The O-Ring Store Does it Best

Why The O-Ring Store leads on precision vulcanized O-Rings: posted Class 2 and Class 3 tolerances, in-house splicing capacity, and Olypsys® Large Format inspection that proves large custom rings meet spec.

Small black O-Ring seated on a bolted stainless process flange, chemical plant piping and tanks softly blurred behind

Butyric Anhydride O-Ring Compatibility: Which Compounds Hold Up

Butyric anhydride O-Ring guide for cellulose acetate butyrate, fragrance, pharma, and agrochemical service: chart ratings, which elastomers to use, and which to avoid.

A fresh black O-Ring next to an old cracked one on a worn steel workbench, with a bag of new O-Rings, a dial caliper and an open parts drawer in warm window light

Do O-Rings Expire? Here's the Straight Answer

Most O-Rings outlast the drawer they sit in. Here's how long each compound really keeps, what ruins them on the shelf and how to tell if an old one is still good.

Small black O-Ring seated on a four-bolt chemical dosing pump flange, wastewater treatment sulfide totes and pipe rack softly blurred behind

Calcium Hydrosulfide O-Ring Compatibility: Which Compounds Hold Up

Calcium hydrosulfide O-Ring guide for leather dehairing, wastewater metal precipitation, and pulp service: chart ratings, which elastomers to use, and which to avoid.

Black O-Ring on a wooden table with white crystalline powder, a beaker of pale amber liquid, and a soft-focus industrial plant background

Potassium Stannate O-Ring Compatibility: Which Compounds Hold Up

Potassium stannate O-Ring guide for alkaline tin plating baths: chart ratings, which elastomers to use around plating tanks, and which to avoid.

Black O-Ring on a wooden table with white crystalline powder, a clear beaker of pale amber liquid, and a soft-focus lab background

Para-Aminobenzoic Acid O-Ring Compatibility: Which Compounds Hold Up

Para-aminobenzoic acid (PABA) O-Ring guide for pharmaceutical and dye intermediates: chart ratings, which elastomers to use, and which to avoid.

Black round-cord EPDM O-Ring on a wooden table with a stainless wall-mounted bottle filling station in the background

EPDM NSF-61 O-Rings: Peroxide-Cured, Chloramine-Resistant Potable Water Seals

Buy EPDM FDA/NSF-61 peroxide-cured O-Rings for chloraminated drinking water, hot water, and food contact. Specs, approvals, and where this 70 duro compound belongs.

Small black round-cord O-Ring beside a clear beaker of pale amber PAG lubricant, modern rotary screw compressor softly blurred in the background

Ucon Lubricant 50-HB-260 O-Ring Compatibility: Which Compounds Hold Up

Ucon Lubricant 50-HB-260 O-Ring guide for PAG compressor, hydraulic, and metalworking fluids: chart ratings, which elastomers to use, and which lack data.

Red SAE J1926 ORB hydraulic fittings with black AS568 900-series boss O-Rings seated on the straight-thread studs

SAE J1926 ORB Boss O-Rings: AS568 900-Series Sizes That Actually Seal the Port

What SAE J1926 O-Ring Boss fittings need from the seal: AS568-901…932 boss O-Rings, how they differ from NPT and JIC, materials, install tips, and a Boss-only size chart.

Black rubber O-Ring with round cord cross-section measured by digital calipers on a printed size chart

The Master O-Ring Size Chart: What It Shows, Why It Helps, and Who It Is For

A practical guide to the handbook Master O-Ring Size Chart: multi-standard sizing, nearest-match search, tolerances, back-up rings, and who gets the most from it.

Clear beaker of amber calcine process liquor with a small black O-Ring submerged in the liquid, mineral processing plant in the background

Calcine Liquors O-Ring Compatibility: Which Compounds Hold Up

Calcine liquors O-Ring guide for mineral processing and metallurgy: chart ratings, which elastomers hold up in aqueous calcination circuits, and which to avoid.

Clear unmarked beaker of aqueous solution with a small black O-Ring submerged in the liquid, water-treatment plant in the background

Ammonium Sulfite O-Ring Compatibility: Which Compounds Hold Up

Ammonium sulfite O-Ring guide for water treatment, pulp and paper, and photo chemistry: chart ratings, which elastomers to use, and which to avoid.

Two white split PTFE backup rings flanking a black O-Ring of the same size, the double back-up arrangement for bidirectional pressure

PTFE Backup Rings: Anti-Extrusion Retainers for Aerospace Hydraulic and Pneumatic Systems

Engineering reference for PTFE backup rings (packing retainers): extrusion mechanics, single versus double configurations, cut geometry, and the MS28774, MS28782, MS27595, AS5781 and AS8791 specifications.

Clear glass beaker of naphtha with a black O-Ring falling into the liquid

Naphtha O-Ring Compatibility: Which Compounds Hold Up

Naphtha (petroleum solvent) O-Ring guide: which elastomers swell or fail, why FKM and nitrile usually win, and how to read the chemical compatibility chart for VM&P and solvent naphtha.

Black Freudenberg N888 nitrile aerospace O-Ring

Freudenberg N888: Low-Temp Aerospace Nitrile O-Ring (70 Duro NBR)

Freudenberg N888 is a 70 durometer low-temperature nitrile (NBR/Buna-N) O-Ring for aerospace: flexible to -65°F, qualified to MIL-G-5514 and SAE AS5440, built to AS28775, MS28775, and MS28784.

ISO 9001:2015 Certified, The O-Ring Store LLC, certified by LRQA

O-Ring Certificates of Conformance: House CoC and Manufacturer's CoC

What certification comes with your O-Ring order: The O-Ring Store's House Certificate of Conformance on every order, the Manufacturer's CoC for aerospace and mil-spec, PPAP, and how to request each.

HNBR vs Buna-N Nitrile O-Rings: Same Fit, Longer Life

HNBR vs Buna-N Nitrile O-Rings: Same Fit, Longer Life

HNBR (Highly Saturated Nitrile) O-Rings drop into the same sizes as standard Buna-N and add higher heat, better wear, and longer service life. Full side-by-side.

How to Measure an O-Ring With Your Phone: Inside Olypsys® Measurement Accuracy

How to Measure an O-Ring With Your Phone: Inside Olypsys® Measurement Accuracy

How Olypsys® measures O-Rings with a smartphone, what actually drives its accuracy, and why gasket measurement is right around the corner.

Five Ways to Avoid Early Seal Failure

Five Ways to Avoid Early Seal Failure

Most premature O-Ring leaks trace back to a handful of avoidable installation mistakes.

How to Measure an O-Ring

How to Measure an O-Ring

Two dimensions, one common mistake, and when to measure the groove instead.

O-Ring compounds

Choosing the Right O-Ring Compound

A three-question shortcut to narrowing down the elastomer you need.