Rubber selection for general fabrication reduces to a small decision tree: identify the operating temperature window, the dominant fluid exposure, the mechanical duty cycle, and the regulatory target, then choose from six families: Natural Rubber (NR), Nitrile (NBR), EPDM, Neoprene (CR), Silicone, and Viton/FKM [S2][S5].
Each elastomer has a published operating temperature range, a chemical compatibility envelope, and a typical hardness window. Misalignment on any one of those three axes is the documented root cause of premature seal, gasket, and mount failures in industrial plants [S1][S3].
Common Elastomer Families and Their Operating Windows
Neoprene (CR) operates from -30 °F to 212 °F, offers moderate oil resistance, and is flame-retardant, which makes it a default general-purpose choice for HVAC gaskets, weatherstripping, and marine components [S4][S5]. Its documented limitation is degradation in strong oxidizing agents and aromatic solvents, so it should not be paired with ester-based hydraulic fluids or ketone cleaning chemistries [S5].
EPDM spans -40 °F to 300 °F and is the strongest outdoor option, resisting UV, ozone, and steam with no protective additives required, so roofing membranes, weatherstripping, and water-system seals default to EPDM in most fabricator catalogs [S4][S5]. The same family is unsuitable for petroleum-oil contact, where it swells and loses mechanical integrity [S2][S5].
Nitrile (NBR) covers -30 °F to 250 °F, resists petroleum, hydraulic fluid, and fuels, and is the workhorse for O-rings, fuel hoses, and transmission seals in automotive and oilfield service [S2][S4][S5]. NBR's weakness is ozone and UV attack unless the compound is PVC-blended or additively protected, which is why indoor or enclosed hydraulic cabinets are its native environment [S5].
Temperature-Extreme and Specialty Grades
Silicone (VMQ) runs from -80 °F to 420 °F, the widest window of any common elastomer, and is FDA-grade compatible for food-processing gaskets, medical tubing, and oven seals [S5]. Its tensile and tear strength are lower than NBR or NR, and it is attacked by oils, fuels, and concentrated acids, so it is rarely the right pick for dynamic abrasion service [S2][S5].
Viton/FKM is the premium choice for high heat and aggressive chemicals, and is the default fluoroelastomer when NBR's 250 °F ceiling is too low or when aromatic hydrocarbons, chlorinated solvents, or strong acids are present [S2][S4]. SBR occupies the low-cost general-purpose slot from -20 °F to 212 °F, with strong abrasion and impact resistance for conveyor skirting, wear strips, and industrial flooring where oil resistance is not required [S4][S5].
Decision Criteria for General Fabrication
The seven questions every fabricator should answer before pulling a compound: (1) fluid contact and concentration, (2) continuous service temperature, (3) peak temperature and duration, (4) UV/ozone exposure, (5) dynamic versus static duty, (6) compression set target at temperature, and (7) regulatory target such as FDA, NSF/ANSI 61, UL, or USP Class VI [S1][S3][S7].
Compression set is the spec most often missed: a compound that seals perfectly at room temperature can take a permanent set above 50 % at its upper service limit and start leaking within weeks, which is why the property is requested at temperature, not at 23 °C/73 °F [S1]. For a deeper view on elastomer cost drivers and the trade-off between unit price and service-life math, see Industrial Rubber TCO: Cost Drivers, Service-Life Math, and 2026 Buyer Trade-offs.
Material Comparison: Six Elastomers Against Four Criteria
Lining the common families against temperature ceiling, oil resistance, weather/ozone resistance, and relative cost gives a one-page spec table that fits inside any fabricator's quote package. The trade-off is real: no single elastomer wins all four columns, which is why "general-purpose rubber" is always a compromise and not a default [S2][S5][S6].
Reference comparison drawn from the operating data above: NR has excellent tensile and abrasion but poor oil/ozone resistance and tops out near 175 °F; NBR covers -30 to 250 °F with strong oil resistance but weak weather resistance; EPDM runs -40 to 300 °F with the best weather/steam profile but fails in petroleum; CR spans -30 to 212 °F with balanced but moderate performance on every axis; silicone spans -80 to 420 °F with the widest window but lower mechanical strength; FKM handles the highest temperatures and the most aggressive chemicals at a premium price [S2][S4][S5][S6].
Application-Specific Defaults That Hold Up in the Field
Anti-vibration mounts and bushings: NR, because of resilience and damping [S2]. Conveyor skirting, chute liners, and wear pads: NR or SBR, where abrasion dominates over fluid contact [S4][S5]. O-rings in fuel and hydraulic service: NBR, 70 to 90 Shore A is the common hardness window [S2][S4]. Outdoor gaskets and roofing: EPDM, including hot-water and steam service [S4][S5]. HVAC and general sealing where some oil is present: CR, with UL 94 flame ratings available on certain compounds [S5]. Food, medical, and cryogenic seals: silicone, with FDA and USP Class VI grades on the market [S1][S5].
For custom-molded components where process (injection versus compression) is part of the spec, the matching guide at How to Choose a Rubber Molded Part walks through cure systems, hardener choice, and flash control alongside material selection. A useful cross-reference for fabricators who also handle rigid polymers is the selection map in POM Types and Classifications, which applies the same criteria-based approach to acetal.
Limitations, Failure Modes, and Specification Gaps
The four documented failure modes for industrial rubber are: (1) chemical attack and swelling, (2) compression set at temperature, (3) ozone/UV cracking on unprotected NR, NBR, and SBR, and (4) abrasion wear in dynamic service [S1][S2][S5]. Each maps to a different family: chemical attack rules out EPDM in oil service; compression set rules out silicone in sustained static loads above 300 °F; ozone/UV rules out unprotected NR outdoors; abrasion rules out silicone in chute and scraper duty [S2][S5].
Spec gaps to watch: hardness is widely quoted in Shore A but is not a stand-alone performance metric, two compounds at 70 Shore A can have very different tensile, elongation, and compression-set behavior [S1]. Tensile and elongation should always be requested alongside hardness, and compression set should be specified at the service temperature, not at room temperature, to avoid a sealed-but-leaking part in the field [S1][S3].
Sourcing, Standards, and Next-Spec Signals
Regulatory targets that drive compound choice in general fabrication include FDA food contact, NSF/ANSI 61 for potable water, UL 94 for flame ratings, and USP Class VI for medical devices; the correct rubber grade must be specified, not just the polymer family, because not every NBR or silicone is FDA-cleared [S1][S3]. For weather and UV exposure, ASTM D1149 (ozone cracking) and ASTM D1171 are the referenced test methods in most supplier datasheets; for compression set, ASTM D395 (Method B) is the standard 22 h/70 °C or 22 h/100 °C test that should appear on the datasheet [S1].
Trackable signals for the next 6 months: monitor whether EPDM sheet pricing stabilizes after the 2025 feedstock volatility, and whether FKM supply tightens on continued semiconductor and aerospace demand, both of which will push general-fabrication buyers toward CR and silicone as second-choice substitutes [S2][S4].
The underlying component specifications are covered under industrial rubber, industrial adhesive, and industrial borescope.