Why not Purple Threadlocker

[Steve Joblin]

I am getting ready to buy some more threadlocker and have a question...

For screws going into metal on our helis, everyone recommends LOCTITE 243 Blue Threadlocker as it is oil tolerant. I read on the Henkel (the company that makes Loctite brand) website that it is recommended for use on ¼ to ¾ fasteners.

Purple LOCTITE 222, on the other hand, is recommended for small screws up to ¼.

I understand that it is not as strong as the blue, but would it perform better since we typically use small size screws?

[Gyropilot]

I've tried both.

My experience has been the low-strength thread locker has very little holding power in the tiny screws we use. It might be adequate.

The medium-strength thread locker seems to hold better, yet isn't so strong as to make screws difficult to remove.

I haven't tried using high-strength thread locker... no need so far.

John

[The_Norwegian]

Vibrations maybe? I would say use blue
I have never used any purple, but I have never lost a screw, metal to metal with blue on my RC vehicles so far.
(PS: That are on cars, not heli or quads etc)

I have recently started to use sticks instead of the bottles with locktite, and they seem to do the same job as the liquid one. Ebay have them, link.

[RaisedByWolves]

Originally Posted by Gyropilot

I've tried both.

My experience has been the low-strength thread locker has very little holding power in the tiny screws we use. It might be adequate.

The medium-strength thread locker seems to hold better, yet isn't so strong as to make screws difficult to remove.

I haven't tried using high-strength thread locker... no need so far.

John

Are you talking about red or green.

Red can craze plastic. I used red way back when on a brand new Clodbuster frame. Put it all together and dropped it from about 2' and it literally exploded.

We use the green at work to set loose fitting bearings and die posts.

If you use it on these tiny screws it is pretty much permanent.