Common Mistakes to Avoid When Using Anaerobic Adhesives

Laurie Gibbons
Adhesive Types, Anaerobic Adhesives
May 12, 2010

Anaerobic Adhesives Curing Tips

Overall the best anaerobic adhesive tip is to ensure the anaerobic adhesive has the two things needed to cause a cure. Namely, contact with metal and no contact with oxygen.

Tip #1

Anaerobic adhesive tip #1 Ensure contact with metal. Following are three examples of adding something between the anaerobic and metal to ensure it seals. Which, in fact, causes it not to cure.

Gasket

A common idea 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 liquid and will further degrade the non-metal components and possibly cause blockages or damage. Use an anaerobic liquid gasket adhesive instead of a conventional pre-formed gasket. This means one bottle of adhesive can make whatever sized or shaped gasket is required, without having to keep the correct (and often fragile to handle and store) pre-formed gasket in stock. Anaerobic adhesives replace traditional gaskets and add the benefits of better stress distribution, improved stock control, and no “bedding in” re-tightening.

Pipe Sealant

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. Replace the tape with a simple application of adhesive sealant that lubricates for easy assembly at the same time that it seals the threaded pipe connection.

Gap

Note another anaerobic adhesive tip is to mind the gap. Do not use anaerobic adhesive in applications when you want to fill gaps larger than 0.5mm. Yes, the anaerobic adhesive is in contact with metal – but the metal only activates cure so far, subsequently, the adhesive in the center of a large gap doesn’t “see” the metal.

Tip #2

Anaerobic adhesive tip #2 Ensure the absence of oxygen.

Wait, what? No air? Relax it is easy – you exclude oxygen naturally when you trap the anaerobic between two pieces of metal. We often receive calls from customers complaining the anaerobic adhesive hasn’t been cured. Often there is a thin layer on the surface (exposed to oxygen) that hasn’t cured. Any squeeze-out that is exposed to air will not cure. This can be managed by either wiping it away or spraying it with an activator such as ASC 10.

anaerobic adhesive and sealant activators

 

Please follow the instructions on the technical datasheet to get the best results.

For further help and advice, please contact Permabond.

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