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How to Spec a Switchgear or Cabinet Gasket: What to Send H-O for a Quote
Enclosure gaskets attract underspecified RFQs because the geometry looks like the whole story: a perimeter strip, a cover frame, a grommet. What the quote actually prices is the service: the rating target the assembly is designed toward, the force the closure can really deliver, the exposure that will spend years attacking the chemistry, and how the part goes onto the line.
This is the ten-item checklist the H-O applications team works from for door gaskets, panel seals, feedthrough grommets, and flange gaskets, drawn directly from the parent application page's own quote-information list, plus what engineering does with each item and what comes back.
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The ten things to send, and what each decides
| Send this | What it decides |
|---|---|
| 1. The joint: door, cover, feedthrough, or flange | The form and the zone: perimeter strip, cover frame, die-cut grommet or split seal, or a bolted-flange gasket where cold flow is the enemy. |
| 2. Enclosure-type target | The NEMA / UL 50E Type or IEC 60529 IP code the assembly is designed toward, treated as a design target for the whole closure, not a gasket certification. |
| 3. Indoor or outdoor exposure | The chemistry: EPDM or silicone for permanently exposed faces (ozone per ASTM D1149), neoprene for sheltered and oil-splash locations. |
| 4. Flammability class, if the program requires one | The grade: V-0 silicone sponge families and the RS series carry UL 94 V-0 per TDS, the SCE neoprene foams carry HF-1, and many fine foams carry no class at all. |
| 5. Closure hardware and force budget | The ASTM D1056 firmness grade: soft for sparse quarter-turn latches, firmer only where bolts or multi-point hardware supply real force; the gasket should work mid-range. |
| 6. Temperature window | Foam versus silicone: organic foams serve ordinary ambients; silicone sponge holds elasticity and recovery across a substantially wider window, with set per ASTM D395 on the TDS. |
| 7. Attachment preference | Plain, PSA-backed, or kiss-cut on liner for line application; the presentation decides assembly speed more than the material does. |
| 8. Door size and splice strategy | Whether the gasket die-cuts from sheet with engineered corners or cuts as one piece from bun stock with no splice joints; tell us the door dimensions and we advise which route is economical. |
| 9. Geometry: DXF, STEP, or PDF, or a sample part | The die program: perimeter path, corner treatment, grommet bore and cutout diameters (the squeeze lives there), and flange bolt pattern for cloth-inserted parts. |
| 10. Prototype and production volumes | Converting method and price structure. Every part is made to order; prototype quantities through full production runs are equally accepted, and MOQ varies by material and part. |
What engineering does with the list
Items 1 through 3 sort the family: EPDM closed-cell foam for outdoor doors, neoprene foam for indoor covers and oil-splash zones, solid silicone for feedthrough grommets, cloth-inserted sheet for bolted flanges, and butyl tape at knockouts and lap joints. Item 4 filters to the classed grades: the V-0 flame-resistant silicone sponge or the RS-series sponge where the program calls a class.
Items 5 and 6 size the firmness and chemistry; items 7 through 9 become the converting plan: PSA lamination, kiss-cut-on-liner presentation, engineered corners, or a one-piece bun-cut gasket from MF1 bun stock. Item 10 sets method and pricing, and the reply cites each recommended grade's TDS values with the test method named.
Defense drawings calling MIL-PRF-6855, AMS 3205, AMS 3208, or MIL-R-83285 designations are quoted against the designation with the manufacturer's certification.
What happens after you send it
- Drawing review. Engineering reviews the enclosure-type target against the vendor TDS: compression range, groove or flange geometry, temperature window, flame-rating need, and outdoor exposure.
- Material direction and quote. A family and grade direction with the TDS attached, the converted format (die-cut, kiss-cut on liner, bun-cut, laminated), and pricing at your quantities.
- Samples. Typically 3 to 5 business days for common die-cut configurations on materials we keep on hand.
- Production. Standard runs ship about two weeks after drawing approval, including kiss-cut-on-liner and PSA-laminated configurations; expedited service is available. Ongoing parts run with material traceability and lot-code TDS records.
Documentation available on request: material technical data sheet, certificate of conformance, lot traceability, and first-article inspection, under our ISO 9001:2015 certified quality management system. H-O die-cuts and converts; we do not mold or extrude elastomers in-house, extruded profiles are coordinated through a partner network, and enclosure Type ratings belong to the complete design under the UL 50E / NEMA 250 evaluations.
The mistakes this checklist prevents
| Spec mistake | What it causes | Checklist item that catches it |
|---|---|---|
| Geometry-only RFQ | A quote for a rubber frame, not a seal; the rating context goes unreviewed | Items 1 and 2 |
| Exposure left off the drawing | The buyer quotes the cheapest foam that fits, and the sun finds it in two summers | Item 3 |
| "Fire-resistant foam" ordered by phrase | The delivered grade's TDS shows no UL 94 class; the audit catches it after the build | Item 4, the grade named |
| Firmness past the force budget | The door bows between latches and leaks at mid-span every storm | Item 5 |
| Set ignored at temperature extremes | The gasket becomes a dead spacer; the first wind-driven rain finds the gap | Item 6, set values per ASTM D395 |
| Spliced gasket on a large-format door | Splice joints in the sealing path where a one-piece bun cut was available | Item 8 |
Frequently asked questions
What information does H-O need to quote an enclosure gasket?
The drawing (DXF, STEP, or PDF) or a sample part, plus the service context: the enclosure-type target (NEMA / UL 50E Type or IP code), indoor or outdoor exposure, any flammability class the program requires, the closure hardware and force budget, the temperature window, and the attachment preference (plain, PSA-backed, kiss-cut on liner). Every part is made to order; lead times are confirmed with your quote.
Does H-O mold or extrude these gaskets, or convert them?
H-O die-cuts and converts. We take sheet, roll, and bun stock from the foam and elastomer manufacturers and die-cut, kiss-cut on liner, water-jet, slit, and laminate it to your drawing; we do not mold or extrude elastomers in-house. That converter framing matters: die-cut gaskets with engineered corners and PSA backing, one-piece bun-cut door gaskets without splices, and laminated stack-ups all come from conversion, and extruded profiles are coordinated through a partner network.
Can you cross-reference the gasket called out on my print?
In most cases, yes. If your drawing calls out a foam or elastomer by a brand grade, engineering identifies a comparable family from the lines we convert, matching on chemistry, ASTM D1056 firmness grade or ASTM D2240 durometer, flammability class, temperature window, and exposure. It is an industry cross-reference, not a guaranteed drop-in, verified against the vendor TDS for your application before quoting, and defense designations are quoted against the document with the manufacturer's certification.
How do I seal cable and connector penetrations through the enclosure wall?
With die-cut grommets and entry seals rather than perimeter material: solid silicone in 30 to 90 Shore A per ASTM D2240 for most single-cable grommets, ultra-soft solid grades for delicate jackets, and a compressible flame-rated sponge around multi-cable bundles and irregular penetrations. Send the cable jacket diameters and the panel cutout dimensions; bore and cutout control the squeeze, and tight-tolerance die-cutting is what makes the grommet grip without cutting.
Send the checklist, get an enclosure-gasket quote
Attach the geometry and as many of the ten items as you have. A sample part works when no drawing exists.
Samples typically ship in 3 to 5 business days for common die-cut configurations on materials we keep on hand; standard production runs about two weeks after drawing approval; expedited service is available. MOQ varies by material and part.
Family-owned in Winsted, Connecticut since 1971 · ISO 9001:2015 certified · OEMs worldwide send us a drawing — and get back their part.
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Send H-O your drawing or describe the part—engineering reviews every RFQ and converts samples on your geometry.
Last updated · Reviewed by H-O Products engineering (ISO 9001:2015 certified converter, Winsted, CT).
References
- UL 50 / UL 50E and NEMA 250 (enclosure types, the design target); IEC 60529 (IP code).
- ASTM D1056 (compression-deflection grades); ASTM D2240 (durometer); ASTM D1149 (ozone); ASTM D395 (compression set); UL 94 (flammability classes, per grade).
- MIL-PRF-6855, AMS 3205, AMS 3208, MIL-R-83285 / AMS-R-83285 (defense and aerospace sealing designations).
- Manufacturer technical data sheets for the EPDM, neoprene, silicone sponge, butyl, solid silicone, and cloth-inserted grades named on the parent application page.
This checklist supports a quotation workflow; it does not constitute design guidance for any specific enclosure, and enclosure Type ratings belong to the complete design under the UL 50E / NEMA 250 evaluations. Grade-level values are confirmed on the manufacturer's current technical data sheet at quote time. All parts are custom manufactured to order; minimum production run quantities vary by material and part. H-O is a die-cut converter, not a raw-material producer, does not mold or extrude elastomers in-house, and does not certify finished enclosures.