I bought some blue threadlocker in a little squeeze tube, and it is a very runny and drippy liquid. Is the substance that comes pre-applied to screws and is dry to the touch just the "stick" version which has hardened in the air? Or something different?

  • There are two basic versions of your standard thread-lock compound -- "adjustable" and "non-adjustable". The former maintains some pliability after application, while the latter is either permanent (break the bolt) or at least a cute little puppy (break out the long arm wrench) if you need to remove it. It's advised to carefully read the labels and consider your options before using any of the stuff. Feb 13, 2019 at 12:56

1 Answer 1


It is hard to say for sure how threadlocker gets pre-applied on bolts at factories (most likely not by hand, but who knows).

However, its polymerization happens after contacting the metal, not because of drying on air.

From the Wikipedia article:

Most thread-locking formulas are methacrylate-based and rely on the electrochemical activity of a metal substrate to cause polymerization of the fluid.

A somewhat counterintuitive property of threadlocker is that it "dries" in airless conditions.

Typically, thread-locking fluids are methacrylate-based, and cure anaerobically.

If the fluid is left in an open container without any contact with metals, it will remain liquid.

  • I put a drop of the blue liquid on a stainless steel screw and let it sit for a couple of hours. It seems to settle into a much thinner coat around the threads than what is found on screws with manufacturer-applied threadlocker that are included in various replacement and upgrade kits. I'm wondering if they're using a different brand or formulation.
    – Tim
    Feb 13, 2019 at 21:59
  • @Tᴚoɯɐuo most likely both brand and amount of liquid and method of application are different. Feb 14, 2019 at 7:09

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