Known as Loctite Superflex Black RTV Silicone

Features and Benefits

General purpose, 1-part silicone adhesive sealant which cures at room temperature to form a tough yet flexible rubber seal.
LOCTITE® SI 593 is a black, general purpose, 1-part RTV (room temperature vulcanizing) acetoxy silicone adhesive and sealant which moisture cures at room temperature to form a tough rubber seal. It will not slump in overhead or vertical applications and has been formulated to withstand extreme temperature cycling, UV light, and ozone. It CANNOT be painted.
  • General purpose, flexible adhesive/sealant
  • Suitable for applications up to 400°F (204°C)
  • Withstands extreme temperature cycling, UV light, and ozone
  • Forms a tough rubber seal/bond to most surfaces
  • Does not harden, shrink, or crack
Read More

Technical Information

Applications Sealing
Chemical basis / base Acetoxy Silicone
Color Black
Cure type Room Temperature Vulcanization (RTV) Cure
Extrusion rate ≥250.0 g/min.
Number of components 1 Part
Specific gravity, @ 25.0 °C 1.84
Storage temperature 8.0 - 21.0 °C

How to

Step by Step Guide

1. Preparation - Cleaning

Clean surfaces with solvent-based (non-CFC), general purpose surface cleaner LOCTITE® SF 7070™ to ensure surfaces are free of dirt, dust, oil and any other contaminants. Allow to dry.

2. Preparation - Tubes only

Cut nozzle at 45° angle to create the proper bead diameter for your application. The appropriate bead diameter is dependent on the gaps that need to be filled, but it is best to start small and increase bead size if necessary. Typical bead sizes range from 1/8” to 1/4”. Screw cut nozzle onto tube for application.

3. Application

Hold package at a 45° angle and apply a continuous bead at the joint interface.

4. Cleanup

Clean up any excess or squeeze-out.


RTV silicone sealants cure on exposure to moisture in the air. Typical skin-over time is 60 minutes and full cure time is 24 hours, but times will vary with temperature, humidity and gap.

Frequently Asked Questions