As the name would suggest, threadlocker is the adhesive you use for your nuts and bolts. Unlike regular adhesives, threadlockers only cures with the absence of oxygen.

You would typically apply it on pesky bolts or nuts that have a knack of loosening or falling off due to vibration. Originally, developed and sold by American Sealants under the Loctite brand (lock tight.. Geddit?) in the 1950s, threadlockers today are as common as cyanoacrylate adhesive aka Super Glue - so there's dime a dozen of threadlocker brands out in the market today.

Typically, most manufacturers would follow the blue and red colours to denote medium and permanent strength as originally used by Loctite - blue can be removed by regular hand tools while red is more of a permanent threadlocker and would require heating the bolt or nut before it can be loosened, but not always as detailed in this video - so it pays to read the fineprints before using it.

CT Hardware carries both the Rewin RY340 as well as the Visbella VS6271. Both are permanent threadlockers and while both can be used for just about any threads including automotive and machinery applications, we typically see these used in the construction industry to keep nuts and bolts on steel structures permanently in place.