Custom Capsule/Slot Gaskets – Instant Quote
Custom Capsule/Slot Gaskets – Instant Quote
A capsule (obround or slot) gasket has straight sides and two semicircular ends — the shape for slotted ports, handholds, and elongated covers. We CNC cut (laser, waterjet, and more) custom capsule gaskets to your exact length and width, no minimum order, shipped within one business day.
Dimensions You Enter for a Capsule / Slot Gasket
| Overall length | End to end, including the rounded ends |
| Width | The straight-side width / diameter of the ends |
| Thickness | 1/16", 1/8", 3/16", or 1/4" |
| Material | Any elastomer or fiber |
Available in every material we stock — neoprene, silicone, EPDM, Buna-N, Viton, PTFE, cork, and fiber. Additional specs on request.
Common Capsule / Slot Gasket Applications
- Slotted port and handhold covers
- Elongated access-hatch seals
- Boiler and tank handhole gaskets
- Oval-style inspection covers
- Cable-entry and gland plates
Capsule / Slot Gasket FAQs
What is a capsule or slot gasket?
A capsule gasket — also called obround or stadium-shaped — has two parallel straight sides and semicircular ends. It seals elongated slotted openings and handholds.
How do I specify a capsule gasket?
Enter the overall length (end to end) and the width. We cut the obround shape to those exact dimensions in your chosen material.
Enter your dimensions in the quote tool above for an instant price on custom capsule / slot gaskets from Fastest Gaskets — no minimum order, ships in one business day.
Need help before you order?
Which material should I pick?
Full comparison on our Materials Guide.
- Hot parts with oil or fuel (engines, exhaust) → Viton (FKM)
- Hot parts, no oil (ovens, HVAC) → Silicone
- Oil or fuel (pumps, hydraulics, petroleum) → Buna-N (Nitrile) — or Viton for higher heat
- Water / outdoor / sun → EPDM
- General automotive or light oil → Neoprene
- Chemicals / aggressive fluids → PTFE (Teflon) — or Viton for high heat plus chemicals
- Soft seal / uneven surfaces / low pressure → Cork blends
Not sure which material fits? Email us at fastestgaskets@gmail.com.
We CNC cut (laser, waterjet, and more) to ±0.015″. Up to 32.5″ × 32.5″ for most materials; the quote tool shows the exact limit for the one you pick. Ships in one business day. Large orders may take longer.
How to measure
- Measure the outside size — diameter for rounds, or length × width for rectangles and squares.
- Measure the inside opening and any holes (ID, bolt holes, bolt circle if it is a flange).
- Note the thickness you need — pick it in the quoter.
- Enter sizes in inches.
- Already have a drawing? Upload a DXF for an instant price.
More detail: Measuring Guide. Materials: Materials Guide.