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Black Loctite SI 598 silicone gasket maker paste in a 70 mL tube

Loctite

Loctite 234609 SI 598 RTV Silicone Gasket Maker 70 mL Black

SKU CH-RSNT-EQ7XZ

Room-temperature-curing black silicone paste seals metal joints up to 0.02 in gaps and withstands -54 °F to 500 °F

  • Product colorBlack
  • Forms reliable gaskets at room temperature in 30 minutes
  • Withstands extreme heat up to 500 °F for demanding seals
  • Remains flexible down to -54 °F in cold environments
  • Fills gaps up to 0.02 in for leak-proof joints
  • Resists oil, alcohol and anti-freeze for lasting performance

Purpose and users

Loctite SI 598 is a black RTV silicone gasket maker supplied in a 70 mL tube. It forms flexible, oil-resistant seals on metal flanges and housings that see alcohol, anti-freeze or automotive fluids.

Sustained-load behaviour

After a 30-minute working time the paste cures at room temperature in one day. The cured seal withstands continuous temperatures from -54 °F to 500 °F and resists oil, coolant and fuel without hardening or cracking.

Upgrade context

It replaces cut gaskets, paper seals or lower-temperature RTV compounds where gaps reach 0.02 in and chemical resistance matters. The jump is worthwhile when a formed-in-place seal must survive repeated thermal cycles and fluid exposure.

How it compares

Measured against everything we stock in Office, Masking & Packing Tape, at today’s prices. Recalculated every night.

Price $18.99
Cheaper than about 65% of the 3,148 comparable items (median $29.99).

Specifications

Product
Brand nameLoctite
Product colorBlack

Questions about this item

Does the SI 598 paste produce strong fumes or heat while it cures over a full day?

It cures at room temperature with a 30-minute working time and reaches full cure in one day, so no external heat is needed and fumes remain typical for an RTV silicone.

What surfaces and tools are required before applying the 70 mL tube?

Clean metal parts, a way to apply a continuous bead within the 0.02 in gap limit, and 30 minutes to assemble before the paste skins over.

Will the cured gasket hold up against the 500 °F peak temperatures in my older engine?

Yes, the product is rated for continuous exposure from -54 °F up to 500 °F and resists oil, anti-freeze, alcohol and other automotive fluids.

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