A very common idea, with unfortunate consequences, is to combine an
anaerobic adhesive with the mechanical method that the adhesive is meant to replace.
For example, using a pre-formed gasket (such as a cork, paper or rubber gasket) with an anaerobic gasket making adhesive will not create an effective seal.
The thought process goes something like this:
'ah-ha, I will make sure this gearbox doesn't spring a leak by using both a gasket and the adhesive, that'll be leak-proof for sure".
Unfortunately it would be much more likely to develop a leak path because the adhesive must be in contact with a metal surface to cure; surfaces such as paper, cork or rubber prevent the adhesive from curing. Uncured adhesive remains a liquid and will further degrade the non-metal components and possibly cause blockages or damage.
Anaerobic liquid gasket adhesive is designed to be used instead of a conventional pre-formed gasket. This means one bottle of adhesive can make whatever sized or shaped gasket required, without having to keep the correct (and often fragile to handle and store) pre-formed gasket in stock.
Using anaerobic
adhesives to replace traditional gaskets has the benefits of better stress distribution, improved stock control and no "bedding in" re-tightening.
It is important to note that an anaerobic adhesive is not the right adhesive to use in applications where the gap to be fill is larger than 0.5mm.
Another similar mishap can occur by combing an anaerobic pipe sealant with PTFE tape on threaded pipe joints. The tape will prevent the sealant from contacting the metal necessary to initiate the adhesive cure.
The adhesive is designed to replace the tape with a simple application that lubricates for easy assembly at the same time that it seals the threaded pipe connection.
First time users of adhesives are advised to follow instructions carefully so that the intended results are achieved.
