Loctite (Henkel)

SI 587 Blue Silicone Gasket Maker

High-performance RTV · US · manufacturer-sourced

Check your container: This countdown is for the High-performance RTV variant. Similar-looking versions may have different times.

How long does Loctite (Henkel) SI 587 Blue Silicone Gasket Maker take to dry?

Short answer

Tack-free: 10–50 minutes after application.
Full cure: 3 days after application.
Gasket makers

Gasket-sealing stages

Assemble, wait, then fill and pressurize

  1. Apply the High-performance RTV to clean, dry flanges
  2. Assemble within the stated time
  3. Fill and run only after the stated cure

This product’s stated stages Quoted at 77°F and 5% humidity

  • Tack-free10–50 minutes
  • Full cure3 days

Worth noticing: Tack-free at 10–50 minutes; full cure at 3 days.

Common mistake: Adding fluid or pressure before the gasket has cured; leaks follow.

Gasket makers

Bond-strength path

Assembly, handling and full load are different stages

1 · AssembleClean, fit and apply the High-performance RTV version correctly.
2 · HoldKeep the joint undisturbed through its set or clamp stage.
3 · LoadUse full cure—not surface firmness—before demanding use.

Time the gasket cure

When did you assemble the joint?
Conditions that affect drying
Where?
Thickness

Stated times

  • Tack-free10–50 minutes
  • Full cure3 days

From Loctite (Henkel) data sheet · checked 2026-10-25. Anything not listed isn’t stated by the manufacturer.

Manufacturer website: loctiteproducts.com

Conditions & fine print
  • Stated conditions: 77°F (25°C) and 5% relative humidity
  • RTV silicone cures from moisture in the air, so cure is slower in dry air and in thick sections. Follow the current data sheet.
  • Region US. Formulas can differ between countries; check your container.
  • Tack-free: At 25°C (77°F) and 50 ± 5% relative humidity.
  • Full cure: Moisture cure; cured-material properties are reported after 7 days at 25°C.
  • Entered from the cited manufacturer documentation. Check the current label for the exact formula and region. Report outdated information
  • Actual results depend on preparation, thickness, ventilation, temperature, humidity, mixing and substrate.

Confirm this is your product

Closely named formulas, colors and regional versions can use different times. Match these details to your container before starting a countdown.

Exact listing
Loctite (Henkel) SI 587 Blue Silicone Gasket Maker
Variant
High-performance RTV
Region
US
Listed use
gasket maker, rtv silicone, flange sealing
Timed stages recorded
tack free, full cure
Source checked
2026-10-25

Documentation: Technical data sheet copy · December-2010, distributor copy

Condition attached to the stated time: At 25°C (77°F) and 50 ± 5% relative humidity.

About this product

A blue RTV gasket maker. Its data sheet gives a wide tack-free range of 10 to 50 minutes and a 72 hour period for full performance properties.

Using this specific product

Loctite (Henkel) SI 587 Blue Silicone Gasket Maker is listed here as the High-performance RTV version for gasket maker, rtv silicone, and flange sealing. For using this product, the useful question is not simply whether the surface looks finished—it is whether the exact next-action milestone shown above has been reached.

Before you start

  • Confirm the package says High-performance RTV; related versions can use different timing.
  • For gasket maker, rtv silicone, and flange sealing, pay particular attention to the exact variant, preparation and environmental conditions.
  • At 25°C (77°F) and 50 ± 5% relative humidity. Moisture cure; cured-material properties are reported after 7 days at 25°C.

How to check readiness

Check the real material or treated area at the slowest location before the next step. The data sheet gives a tack-free time of 10 to 50 minutes. Reserve full cure for demanding use, chemicals, washing, immersion or load—not merely gentle handling.

Avoid this mistake

The first visible change is not always the manufacturer’s final-use milestone.

Compare with similar products

Keep going

Questions

How long does this product take to dry?

Loctite (Henkel) states: The data sheet gives a tack-free time of 10 to 50 minutes. Conditions: At 25°C (77°F) and 50 ± 5% relative humidity.. The data sheet says full performance properties will develop over 72 hours. Conditions: Moisture cure; cured-material properties are reported after 7 days at 25°C.. These are the manufacturer’s stated times, not a guarantee.

How long before an engine with Loctite 587 Blue can be run?

The data sheet gives 10 to 50 minutes tack-free and says full performance properties develop over 72 hours at 25°C and about 50% humidity. It does not give a run-in time; check the engine maker's instructions.

How long does this product take to fully cure?

Loctite (Henkel) states: The data sheet says full performance properties will develop over 72 hours. Conditions: Moisture cure; cured-material properties are reported after 7 days at 25°C.. These are the manufacturer’s stated times, not a guarantee.

What affects how long this product takes to dry or cure?

RTV silicone cures from moisture in the air, so cure is slower in dry air and in thick sections. Follow the current data sheet. Follow the product label for your conditions.

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