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How to Spec Aerospace EMI Gaskets: What to Send H-O for a Quote
Aerospace EMI gaskets attract underspecified quote requests because the geometry looks like the whole story: a perimeter gasket, a connector frame, a strip of foil. What the quote actually prices is the duty behind it, the exposure at the seal, the galvanic pairing, the flammability call-out, the closure force, and the type designation the EMC plan requires. This is the ten-item checklist the H-O applications team works from, what engineering does with each item, and what comes back.
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The ten things to send, and what each decides
Aerospace EMI gaskets attract underspecified RFQs because the geometry looks like the whole story: a perimeter gasket, a connector frame, a strip of foil. What the quote actually prices is the duty behind the geometry: the exposure at the seal, the galvanic pairing, the flammability call-out, the closure force, and the type designation the EMC plan requires.
This is the ten-item checklist the H-O applications team works from for conductive gaskets, environmental partners, and foil tapes, drawn from the parent application page's own engineering-review list, plus what engineering does with each item and what comes back.
| Send this | What it decides |
|---|---|
| 1. Exposure class at the seal | The base polymer. Dry bay stays on standard conductive silicone; fuel or oil mist moves to fluorosilicone; salt fog and exterior move to corrosion-resistant grades. |
| 2. Mating-surface finish and galvanic pairing | The couple. The flange alloy and finish (MIL-DTL-5541 class) plus the gasket grade set the galvanic behavior per the SAE ARP1481 discipline. |
| 3. Flammability call-out | Run as a gate at the start. A UL 94 V-0 requirement selects the flame-retardant conductive grades before compression and groove decisions are tooled. |
| 4. Closure force and groove geometry | Solid versus sponge. Low or uneven force favors conductive sponge; demanding bond paths where the latch delivers favor high-conductivity solid. |
| 5. Type designation or shielding data | The MIL-DTL-83528 type the drawing carries, or the IEEE 299 shielding-effectiveness and ASTM D991 resistivity the EMC plan needs, verified against the maker TDS and QPL at quote. |
| 6. Combined sealing need | One gasket or two. Where the joint must keep weather or fluids out as well as shield, a dual-seal construction laminates the environmental seal to the conductive element. |
| 7. Web and feature geometry | Minimum web widths matched to the material's tear behavior for fine connector gaskets, because a torn web fails the next EMC scan at that connector. |
| 8. Cycle life at the joint | Compression-set behavior as a primary selection property for anything that opens and closes, with open-close frequency on the drawing. |
| 9. Geometry and liner presentation: DXF, STEP, or PDF | Outline, groove fit, kiss-cut-on-liner delivery, and lamination order, the items that decide whether small conductive parts survive handling. |
| 10. Prototype and production volumes | Converting method and price structure. Every part is made to order; prototype quantities through production runs are equally accepted, and MOQ varies by material and part. |
What engineering does with the list
Items 1 and 2 pick the base polymer and grade by exposure and couple: standard SSP502 silicone for dry bays, fluorosilicone for mist paths, and corrosion-resistant grades for exterior couples. Item 3 gates the flame-retardant V-0 grades where the call-out demands. Item 4 splits the closure-force families between EC-2130 sponge and EC-2265 solid.
Item 6 builds the dual-seal with kSil V-0, and item 7 sets the web geometry, with conductive foil tape for terminations. Items 8 through 10 become the cycle-life selection, the converting plan, and the price structure.
What happens after you send it
- Drawing review. Engineering reviews the joint against the vendor TDS: exposure, mating-surface finish and galvanic pairing, flammability call-out, closure force and groove geometry, and the type designation or shielding data.
- Material direction and quote. A family and grade direction with the TDS and type alignment, the converted format (die-cut, kiss-cut on liner, dual-seal lamination), 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 fine-web parts and dual-seal laminations; expedited service is available. Ongoing parts run with material traceability and lot-code TDS records.
Documentation available on request: material technical data sheet, type-designation and QPL alignment, certificate of conformance, and lot traceability, under our ISO 9001:2015 certified quality management system. H-O is a die-cut converter, not a raw-material producer: we do not manufacture the raw conductive elastomers or foils, we do not independently certify shielding effectiveness, and EMC qualification and platform certification belong to the box builder.
The mistakes this checklist prevents
| Spec mistake | What it causes | Checklist item that catches it |
|---|---|---|
| Standard silicone in the mist path | Swelling, lost bond pressure, failed margins | Item 1, exposure class |
| Conductive gasket on a bare exterior flange | Galvanic corrosion, open bond path | Item 2, couple and finish |
| V-0 requirement found after tooling | Re-opened compression and groove decisions | Item 3, flammability gate |
| Solid gasket on a low-force door | Set, hinge-line RF leak | Items 4 and 8, force and cycle life |
| Fine web below the tear limit | Tears at assembly, fails next EMC scan | Item 7, web geometry |
| Shield and weather seal stacked late | Weather reaches the conductive element | Item 6, dual-seal designed in |
Frequently asked questions
What information do I need to send H-O to quote an aerospace EMI gasket?
Ten items turn the geometry into a quotable drawing: the exposure class at the seal, the mating-surface finish and galvanic pairing, the flammability call-out, the closure force and groove geometry, the type designation or shielding data, the combined-sealing need, the web and feature geometry, the cycle life at the joint, the geometry and liner presentation as DXF, STEP, or PDF, and the volumes. Send what you have; engineering frames the rest and flags any assumption.
Can H-O cut fine-web connector gaskets in production quantities?
Yes, and the web geometry is treated as a converting specification because small conductive parts are shielding-critical parts. Minimum web widths are matched to the material's tear behavior, the parts are kiss-cut on liner so they survive handling, and incoming inspection looks at the webs, not just the outlines. A connector-flange gasket with webs torn at assembly passes continuity checks, ships, and fails its next EMC scan at exactly that connector, so the converting quality is part of the shielding spec.
How should the flammability call-out be handled in the spec?
Run it as a gate at the start, not a late check. If a grade is selected on electrical merit alone and a UL 94 V-0 requirement surfaces later, the substitution re-opens compression, galvanic, and groove decisions that were already tooled. The flame-retardant conductive grades carry V-0 listings on their TDS, per grade and thickness, so a spec that starts with the flammability gate selects a grade that already clears it and never pays the retrofit. Send the flammability call-out with the first drawing.
Can H-O cross-reference a MIL-DTL-83528 type designation on my drawing?
In most cases, yes. If your drawing carries a MIL-DTL-83528 type designation or a brand part number, engineering identifies a comparable grade from the lines we convert, matching on type designation per MIL-DTL-83528, shielding effectiveness per IEEE 299, resistivity per ASTM D991, and the exposure and galvanic behavior the joint requires, with QPL status verified against the maker's current documentation at quote. It is an industry cross-reference, not a guaranteed drop-in, verified against the vendor documentation before quoting.
What lead time should I expect for samples and production?
Every EMI gasket is made to order, including samples. Samples typically ship in 3 to 5 business days for common die-cut configurations on materials we keep on hand; standard production runs ship about two weeks after drawing approval, including kiss-cut-on-liner fine-web parts and dual-seal laminations; expedited service is available when timing is critical. MOQ varies by material and part, and prototype quantities through production runs are equally accepted.
Send the checklist, get an EMI gasket quote
Attach the geometry and as many of the ten items as you have. If something is unknown, say so; the review proceeds with the assumption flagged.
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.
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Related reading
Request a quote for your aerospace & defense EMI shielding gasket part
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
- MIL-DTL-83528 (conductive elastomer specification and type designations, by designation; QPL verified at quote).
- IEEE 299 (shielding-effectiveness measurement); ASTM D991 (volume resistivity of conductive rubber).
- SAE ARP1481 (corrosion control and electrical conductivity, by designation); MIL-DTL-5541 (conversion coatings on aluminum, by designation).
- MIL-STD-461 (EMC requirements, cited qualitatively); RTCA DO-160 (environmental and EMC framing); UL 94 (flammability listings, per grade).
- Manufacturer technical data sheets for the conductive silicone, fluorosilicone, corrosion-resistant and flame-retardant grades, conductive sponge and solid, foil tape, and environmental silicone sponge named on the parent application page.
This article summarizes EMI conductive-gasket material-selection principles for aerospace and defense electronics using the families and published test methods cited on the parent application page. Comparisons are qualitative; per-grade values, shielding-effectiveness data, and MIL-DTL-83528 type alignments quoted are maker-TDS figures and must be confirmed on the manufacturer's current technical data sheet and QPL status at quote. Standards (MIL-DTL, MIL-STD, IEEE, SAE ARP, ASTM, UL) are cited by designation for context, not as a claim of qualification.
H-O is a precision die-cut converter, not a raw-material producer, and does not perform EMC testing, certify shielding effectiveness, or hold platform certifications; those belong to the box builder and its test houses.