Gasket material
Mica Gasket Material
Mica gasket sheet is phlogopite mica flake bound with a resin, sometimes over a tanged stainless insert, for hot dry gas joints at temperatures where graphite oxidizes: exhaust, furnace, burner and turbine flanges. Tanged mica is not a waterjet material, so mica gaskets are supplied cut by the sheet maker or a cutting partner and quoted from your drawing.
- Family
- Phlogopite mica sheet
- Temperature
- To 950 C (1742 F) unreinforced; to 900 C (1652 F) tanged
- Thickness
- 0.4 mm to 3.2 mm
- Formats
- Sheets 1000 x 1200 mm
- Designations
- Maker grade callouts (MICALIT® F, Milam® PSS)
- Product
- Supplied cut to your drawing by the sheet maker or a cutting partner
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.
What mica seals
Mica takes over from graphite where the gas is hot and oxidizing: exhaust manifolds and turbochargers, furnace and kiln doors, burner and heater flanges, and turbine and fuel-cell hot-gas ducts. The cited sheets are rated to 950 C unreinforced and 900 C with a tanged insert, at pressures up to 5 bar [S1, S2]. The mica flakes are inert to solvents, acids and alkalis, and the resin binder burns out in service, leaving the mineral to do the sealing.
It is a low-pressure, hot-gas sheet, not a liquid or high-pressure gasket. For hot liquid or steam under pressure, flexible graphite is the material; below about 200 C, compressed fiber costs far less.
How mica gaskets are supplied
Mica sheet is usually ordered tanged for handling strength, and tanged sheet does not go on the waterjet: the jet lifts the facing off the metal. Mica gaskets are therefore supplied cut by the sheet maker or a cutting partner, quoted from the same DXF, DWG or PDF as any gasket here. Send the drawing, the maker's grade if the print names one, the thickness and the quantity.
Specifications
Mica specifications
| Property | Value (in / mm, C / F as stated) | Source |
|---|---|---|
| Composition, unreinforced | Phlogopite mica flakes impregnated with a resin binder (Donit® MICALIT F) | [S1] |
| Composition, tanged | Mica sheet with one perforated stainless steel insert, EN 1.4401 / AISI 316(L), 0.1 mm thick (KLINGER® Milam PSS) | [S2] |
| Temperature, unreinforced | To 950 C (1742 F) | [S1] |
| Temperature, tanged | To 900 C (1652 F) | [S2] |
| Pressure | 5 bar (72 psi) maximum on both cited sheets | [S1, S2] |
| Thickness, unreinforced | 0.4, 1.0, 1.5, 2.0 and 3.0 mm | [S1] |
| Thickness, tanged | 1.3, 1.5 and 3.2 mm | [S2] |
| Formats | Sheets 1000 x 1200 mm (unreinforced) | [S1] |
| Designations | Maker grade callouts; no ASTM F104 line callout is cited for mica here | [S1, S2] |
How we cut it
Mica, felt and flexible graphite are the sheets on this index that do not go on our waterjet: tanged and metal-inserted sheet is not a waterjet material, and mica sheet is usually tanged, so mica gaskets are supplied cut by the sheet maker or a cutting partner rather than cut in our shop. They are quoted from the same drawing. Send a DXF, DWG or PDF with the grade, the thickness and the quantity, and the routing is settled before the quote.
Where Mica is used, and the usual alternatives
The print or the sheet datasheet governs; these are the sheets usually specified instead:
- Flexible graphite: when the joint is hot but not oxidizing, or carries liquid or pressure.
- Compressed non-asbestos fiber: when the joint runs below the fiber sheet's limit.
- Silicone sponge: when a soft door seal is wanted on a hot enclosure below 200 C.
- Filled PTFE: when the medium is a chemical rather than a hot gas.
Related gasket materials: Flexible Graphite Gasket Material, Compressed Non-Asbestos Fiber (CNAF) Gasket Material, Silicone Sponge Gasket Material, Filled PTFE Gasket Material. The full index is on the gaskets hub; send the drawing through request a quote.
Frequently asked
How hot can a mica gasket run?
The cited unreinforced sheet is rated to 950 C and the tanged sheet to 900 C, both at up to 5 bar. Heat is not the limit; pressure and liquid media are.
Why mica instead of graphite?
Graphite oxidizes in hot air above its rating. Mica does not, so it takes the hot, dry, oxidizing gas joints graphite cannot.
Do you waterjet-cut mica?
No. Mica sheet is usually tanged, and tanged sheet does not go on the waterjet. Mica gaskets are supplied cut by the sheet maker or a cutting partner and quoted from your drawing.
Is mica a pressure gasket?
No. Both cited sheets are limited to 5 bar. Hot pressurized joints want flexible graphite or a metal gasket.
What should the print say?
The maker's grade if known, tanged or unreinforced, the thickness and the quantity, with a DXF of the shape.
Sources
- [S1] Donit MICALIT F Mica Gasket Sheet, GTEEK, https://www.gteek.com/donit-micalitr-f-mica-gasket-sheet, accessed 2026-09-13.
- [S2] KLINGER Milam PSS, KLINGER Thermoseal, https://www.klinger-thermoseal.com/products/klinger-milam-mica-gasket-materials/klinger-milam-pss/, accessed 2026-09-13.
MICALIT, Milam, KLINGER and Donit are trademarks of their owners. No affiliation or endorsement is implied.
Related guides
Send the Mica 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. These parts are cut by the sheet maker or a cutting partner and quoted from your drawing; a Conquest representative replies.
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