Project Description

Gemini Kaps®

Streamlining precision sealant application to backside nut plates and bolts for consistent, high quality seals

Gemini Kaps are designed to assist technicians with the tedious job of applying sealant to aircraft fasteners. With the aid of custom molds, “twin seals” are formed with consistent quality from fastener-to-fastener allowing technicians to spend more time getting the job done rather than going back and touching up areas that do not meet quality or spec.

The majority of fasteners used in the maintenance and repair of aircraft structures are “wet installed” with a qualified aerospace sealant applied during installation to seal out moisture and provide critical corrosion protection. This hand-applied process is time consuming, labor intensive, and technician dependent, which leads to inconsistent and excessive sealant application in addition to increased aircraft weight. SMRC’s Gemini technology delivers consistent, high quality seals.


  • Custom preformed molds for fast, simple, and accurate sealing
    Gemini Kaps are designed to meet customer-defined specifications to ensure a precise amount of sealant is consistently applied to each fastener.

  • Minimal user expertise or training required, even in difficult areas
    Gemini Kaps are easy to use, even in tight or hard to reach spaces, to quickly produce a high quality seal whether being used by a novice or expert sealer.

  • Manufactured from self-releasing polypropylene for easy removal
    Gemini Kaps are injection molded using high quality polypropylene material proven to self-release from sealant and sourced from multiple U.S. suppliers.

  • Colored transparent finish for quick selection and FOD prevention
    Gemini Kaps are brightly colored to correspond with fastening element sizes and reduce foreign object debris (FOD) concerns with a degree of transparency for sealant fill quality control.

  • Precision dimensions for consistent sealing and weight reduction
    Gemini Kaps are designed to produce uniform sealant profiles, reducing operator-dependent inconsistencies which can often lead to excess weight.


  • Time savings
    Gemini Kaps have been shows to reduce the time of applying sealant by as much as 1 minute per fastener.

  • Sealant reduction
    Gemini Kaps have been shows to reduce the amount of sealant by as much as 50%.

  • Weight reduction
    Reduction in sealant required to form a seal directly correlates to weight reduction.

  • Quality inspection
    The “twin seal” feature of Gemini Kaps allows quality control inspectors to notice defects more readily, reducing quality inspection time.

  • Reduced training
    Technicians new to sealing are able to produce seals with quality and time comparable to “sealant experts” with minimal training.


For more information or to request a quote, please email

Gemini Kaps for
Eddie Bolts

Gemini Kaps for Eddie Bolts come in various diameters to seal any fastener size and feature an integral pin for easy centering over bolt splines with side grips to aid in removal.

Use instructions

Gemini Kaps for
Enclosed Dome Nutplates

Gemini Kaps for enclosed dome nutplates are designed to facilitate sealant exclusion from the upper dome areas regardless of dome height.

Use instructions

Gemini Kap
Custom Solutions

Gemini Kaps for other fastener types can be developed to fit your needs.