Gasket material
Hypalon® (CSM) Gasket Material
CSM, long sold under the Hypalon name, is chlorosulfonated polyethylene: a rubber sheet that shrugs off ozone, sunlight, oxidizing chemicals and weather better than neoprene. It is the outdoor, chemical-plant and electrical-enclosure gasket sheet. We cut it to your drawing on the waterjet.
- Family
- Chlorosulfonated polyethylene (CSM)
- Temperature
- -40 C to 120 C (-40 F to 248 F), commercial 60 A; -35 C to 125 C (-31 F to 257 F), Hennig Gasket listing
- Thickness
- 1/16 in to 1/4 in
- Formats
- Rolls 36 in wide; adhesive backing available
- Designations
- ASTM D1418 CSM; ASTM D2000 CE line callouts
- Product
- Sheet gaskets waterjet-cut to your drawing in Orange, California
Figures are the cited maker or standards values; the sheet datasheet and your application govern the final choice.
Every common gasket sheet material is quick for us to source, and we cut it to your print on our waterjet.
What CSM seals
CSM resists ozone, ultraviolet light, oxidizing acids, hypochlorite and weather, and it keeps its color and flexibility outdoors where neoprene chalks and cracks. That puts it on chemical-plant covers, outdoor electrical and telecom enclosures, water-treatment equipment and roof and tank seals. Moderate oil resistance is a bonus; aromatic fuels and ketones are not for it.
Two published ratings are shown: -40 C to 120 C for the commercial 60 A sheet and -35 C to 125 C on the Hennig Gasket listing [S1, S2]. For hotter service or fuels, Viton®; for plain outdoor water service at lower cost, EPDM.
The Hypalon name
Hypalon was the DuPont trade name and the sheet is still ordered by it. Suppliers now label the same polymer CSM, and ASTM D2000 prints use the CE type-class letters. Either name on the drawing gets the same sheet; add the durometer and thickness.
Specifications
Hypalon (CSM) specifications
| Property | Value (in / mm, C / F as stated) | Source |
|---|---|---|
| Composition | Chlorosulfonated polyethylene, ISO/ASTM designation CSM | [S2] |
| Durometer | 60 plus or minus 5 Shore A | [S1, S2] |
| Temperature, commercial 60 A sheet | -40 C to 120 C (-40 F to 248 F) | [S1] |
| Temperature, Hennig Gasket listing | -35 C to 125 C (-31 F to 257 F) | [S2] |
| Tensile and elongation | 700 psi and 300 percent (commercial sheet); 1400 psi and 350 percent (Hennig Gasket listing) | [S1, S2] |
| Thickness | 1/16, 3/32, 1/8, 3/16 and 1/4 in | [S1, S2] |
| Formats | Rolls 36 in wide; plate finish; pressure-sensitive adhesive available | [S2, S1] |
| Designations | CSM under ASTM D1418; ASTM D2000 CE type-class on prints | [S2] |
How we cut it
Gaskets are waterjet-cut to your drawing in Orange, California. Send a DXF, DWG or PDF with the thickness, the material or the specification callout, and the quantity. There is no die to build, so a single prototype and a repeat run go through the same setup, and a revision needs only a new file. The sheet comes from the sheet makers we buy from, to the callout on your print; the cutting is ours. CSM is a chlorinated rubber, and laser cutting is never used on it because it gives off hydrogen chloride when burned; the waterjet cuts it clean.
Where Hypalon (CSM) is used, and the usual alternatives
The print or the sheet datasheet governs; these are the sheets usually specified instead:
- Neoprene: when weather resistance is wanted at lower cost and the chemical exposure is mild.
- EPDM: when the outdoor service is water or steam with no oil or oxidizing chemicals.
- Viton sheet: when the joint runs hotter or carries fuel or aromatic solvents.
- Butyl: when gas tightness matters more than chemical resistance.
Related gasket materials: Neoprene Gasket Material, EPDM Gasket Material, Viton (FKM) Gaskets, Butyl Rubber Gasket Material. The full index is on the gaskets hub; send the drawing through request a quote.
Frequently asked
Is Hypalon still made?
The original DuPont product was discontinued, and the polymer is now sold as CSM by other makers. Sheet ordered as Hypalon is supplied as CSM.
What makes CSM different from neoprene?
Better ozone, ultraviolet and oxidizing-chemical resistance, and it keeps its color outdoors. Neoprene is the cheaper choice where those do not matter.
How hot can a CSM gasket run?
The cited sheets are rated to 120 C and 125 C respectively, with low limits of -40 C and -35 C. Check the maker's sheet for the grade on your print.
Can CSM be laser-cut?
No. It is chlorinated and gives off hydrogen chloride when burned. It is a waterjet material.
What durometers and thicknesses are published?
The cited sheets are 60 A, in 1/16 in through 1/4 in. Other durometers are sourced to order.
Sources
- [S1] Commercial Grade CSM (formerly Hypalon), 60 Durometer, American Rubber Products, https://americanrubberproducts.com/rubber-sheet/commercial-grade-csm-formally-hypalon-60-durometer/, accessed 2026-09-13.
- [S2] Hypalon Gaskets & Sheet Material, Hennig Gasket & Seals, https://www.henniggasket.com/hypalon-gaskets, accessed 2026-09-13.
Hypalon is a trademark of its owner; Viton is a trademark of The Chemours Company. No affiliation or endorsement is implied.
Related guides
Send the Hypalon (CSM) gasket drawing and the quantity
Upload a DXF, DWG or PDF of the gasket with the quote request, or a photo of the part with a ruler if no drawing exists. Add the sheet thickness, the durometer or grade, the quantity and whether adhesive backing is wanted. Gaskets are cut in our own shop in Orange, California; a Conquest representative replies.
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