1) Flat-filled 1-foot product – stock design except addition of elastomer gasket between end plates. This was an attempt to see if the fixtures could be filled in a horizontal layout, with the lens set into the un-cured silicone.
2) Vertically-filled 1-foot product with edges and end-plate sealed with silicone. This was an attempt to see if fully assembled fixtures minus the end-plate could be easily filled in a vertical layout.
3) Sealing options for the lens and/or end plates:
|Complete fill||Complete fill||Complete fill|
Total hands on time for a standard 2ft product is approximately 20 min (Scott). The total incremental hands-on time for encapsulant filled fixtures is 5 to 10 min per unit (based on a batch size of 10 units).
Using an encapsulant to create a water tight (IP67 or better) fixture has been demonstrated, and is technically feasible. The added cost and manufacturing complexity may make this unattractive in comparison to a new linear fixture design. However, this route does provide an interim solution for water tight Class 1 Division 2 fixtures, and also may provide an option for Class 1 Zone 1 use if an UL94 V0 encapsulant is used. This design will not fulfill Class 1 Division 1 requirements however, as they need the fixture to be rated as either explosion proof or intrinsically safe.
Dow Sylgard 184
UL 94 V0
|> 90% (1cm PL)||Good||? (clear)|
Yellow With Age
|Prob. OK||Prob. OK||Prob. OK|
Cure Temp (°C)
Cure Time @ 100°C
|1 hour||1 hour||35 min|
Working Time @ 25°C (hours)
Thermal Conductivity (W/m.K)
Shore A Hardness
Dielectric Strength (kV/mm)
Tensile Strength (psi)
MSDS Component A
MSDS Component B
|gloves, eye protection||gloves, eye protection||gloves, eye protection|