# What type of glue would you use on set potentiometer screws on a PCB?

I want to set my potentiometer screws and then glue them in place so they will not be readjusted by the end user and I have seen green adhesive on them before? Any suggestions as to what is best to use on this type of application? Thank you.

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Place it in a box and leave the variable in case there is a reason to "recalibrate" whatever you had to calibrate. Why does it matter if an end-user breaks a device you sold them. They either have to pay you to fix it or to buy a new one. Even better, they easily resolved a malfunction and are impressed that you allowed your product to easily be repaired. This is not meant to say you may not have a reason, just something to think about. – Kortuk Jan 12 '12 at 19:34
Nail varnish...? – Majenko Jan 12 '12 at 19:45

Hot glue might be your best bet, since it can be removed if one ever has to readjust the setting for some reason. You can get inexpensive guns like this one at any hardware store.

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 Thank you for your time. – Ronda Bruecker Jan 12 '12 at 19:56

Loctite is often used. However there are many type. In general you hear people talk about blue, green and red (242, 290, and 271). Blue prevents inadvertent movement due to vibration and such. With moderate force the pot could be turned. Green is stronger, usually you need to apply a little heat before it can be turned. Red requires a lot of heat and would probably destroy the pot.

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 Jim, you are awesome! Thank you...... – Ronda Bruecker Jan 12 '12 at 22:14 +1 -- thanks; I wasn't familiar with the individual product #s. – Jason S Jan 12 '12 at 22:57

If you want something temporary, hot glue is fine.

If you want something permanent, the canonical brand name for threadlocking compounds is Loctite. Not sure which Loctite compound to recommend -- they're usually not cheap ($40-$50 per 50ml bottle), but they're designed to retain mechanical screws despite vibration & temperature cycling. For a potentiometer, you could probably get away with general-purpose cyanoacrylate (aka Superglue sold in most stores).

Something to be aware of though: Whatever you use, make sure it's not corrosive. From Murata's website:

Can the rotor and adjustment shaft be thread-locked after adjustment?

The only products which can be thread-locked are hermetically sealed products whose wiper and resistive element are not exposed.

Use thread-locking adhesive which does not contain substances that can corrode metals, such as chlorine and sulfur. When using thread-locking adhesive, carefully evaluate its performance on an actual potentiometer.

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