I'm familiar with a number of different colors of thread locker and the strength/usage guidelines. I've never heard of "hardening" vs. "non-hardening" until today though.

The front sprocket installation guide for my Katana specifically requires "non-hardening thread locker" while totally leaving out any mention of strength. If I'd not seen that line, I would have just used blue... Now though I'm wondering as I have no idea if blue is hardening or not. Spec sheets and Google have been no help either.

  • Do the bolts enter any kind of coolant or oil passage? Are they blind holes or though holes?
    – vini_i
    Commented Jun 8, 2017 at 0:24

3 Answers 3


Although I can't imagine it would be needed for your application, there is a truly non-hardening thread locking compound available. Vibra-Tite VC-3 is an acrylic polymer that dries to a resilient plastic substance as the solvent evaporates. It will allow the fastener to be re-torqued or even be removed and reused while still remaining effective. It's slightly more expensive and not as easily found on the shelf but can be bought online.


The Loctite brand fastening sealants are Anerobic sealants that cure in the absence of air. That is why they cure when your fastener is assembled and they ask that you wipe away any excess. Whether they are considered Hardening sealants or not I don't know. Any Loctite sealant, including the red, will come undone and yield to the application of heat. I am not talking about concentrated heat as in an acetylene torch, but soft heat as from a propane torch. A soft or non hardening sealant would be one like an RTV (Room Temperature Vulcanizing) Silicon sealant. Me, I use Loctite sealants on all my motorcycle parts that are not safety wired.


All threadlockers harden, depending on type how hard the cure, blue hardens and can be removed with hand tools but will not vibrate loose, Red gets really hard and will require heat to remove.

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