Custom Ring Capsule/Slot Gaskets — Oblong ID
Custom Ring Capsule/Slot Gaskets — Oblong ID
A ring capsule gasket is an obround frame — a capsule shape with a matching capsule cutout — for sealing around slotted openings and handhole covers. We CNC cut (laser, waterjet, and more) custom ring capsule gaskets to your exact dimensions, no minimum order, shipped within one business day.
Dimensions You Enter for a Ring Capsule / Slot Gasket
| Outer length & width | Outside of the obround frame |
| Inner length & width | The obround cutout |
| 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 Ring Capsule / Slot Gasket Applications
- Boiler and tank handhole covers
- Slotted inspection-port frames
- Elongated hatch perimeter seals
- Manway and access-cover gaskets
- Gland and cable-entry frames
Ring Capsule / Slot Gasket FAQs
What is a ring capsule gasket?
A ring capsule gasket is an obround (stadium-shaped) frame with a matching obround cutout, used to seal around an elongated slotted opening such as a boiler handhole.
How do I measure a ring capsule gasket?
Enter the outer length and width and the inner (cutout) length and width. We cut the obround frame to those exact dimensions.
Enter your dimensions in the quote tool above for an instant price on custom ring 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.