Which kind of threadlock is plastic compatible? TKs

....the regular blue threadlocker is OK with just about anything, even plastic screws going into wood.

FBD.

epoxy?

david

You shouldn't need thread lock on plastic and standard locktite will attack most plastics making them brittle and prone to failure. A SMALL drop of medium ca will work if you must but threading into plastic usually doesn't require it.

That would work once!

..... Thread-locker IS a plastic....

Try this if you want. Place a drop of locktite (threadlocker) on a plate and wait for it to dry. After a few weeks it should still be a liquid. Locktite becomes a solid in the asence of oxygen. It is an anarobic compound. So why does it not work with plastics? For the same reason that it does not harden inside the plastic bottle. Many plastics are pourus to oxygen, so loctite will remain a liguid. I may have a few things wrong here. Manybe others can add something here. It has been over 40 years since I read these things.

....Lock-tite does not become hard in the bottle because there is air in the bottle.
If there was no air, there would be no liquid in the bottle. Plastics are not porous.

Yes, it does get hard in the absence of air. Lock-Tite works fine with a nylon screw....


....in wood. It will also work fine with a metal screw.....in plastic.

I am concerned about the threadlock attacking the servo arm when it is applied to the bolt /nut that holds the Dubro Ball links . I am actually applying it to metal bolt and nut but they are contacting plastic.

What you are looking for is called "anaerobic thread locker"; what old-time heli guys used to know as "the purple stuff".

I have no idea who, if anyone, makes it these days. And I don't remember who made the stuff we used; it was in a white plastic bottle and was purple in color, is all I remember.

But it could be used on the plastic-framed helicopters of the day without issues. We used it on servo arms too, for extra security on the balls that the links popped onto too.

However, for your stated application, a drop of medium CA would do the trick, I think...

.

From the loctite web site. It doesn't mention whether it will damage plastics but it does say it is not effective for locking plastic threads

http://www.loctiteproducts.com/quest...rme=124#cat124

Question
I used Threadlocker on a metal bolt and a plastic nut. Why didn't it stick?

Answer
Threadlockers should only be used on metal-to-metal applications, because the Threadlocker turns into a plastic-like substance.

For my application I am using it on metal to metal . I am only concerned whether it will cause the plastic servo arm to deteriorate over time because I am sure the threadlock will wick into the servo arm hole . I will use medium c/a instead. BTW Loctite 425T ( Assure surface curing threadlock ) is supposed to be compatible with plastics . http://www.ellsworth.com/display/pro...5&Tab=Vendorss

First, proper use of thread locker will use only a very small dab on the threads and will not effect your servo arm. We do it all the time with servo arms and ball studs on helis.

Hi BarracudaHockey
Thanks for confirming that the plastic bottles Loctite uses allow air to migrate thru the sides. I first read that around 1966 and when someone above contradicted that I naturally wondered if something had changed or maybe my memory was failing.