Has anywone used Locktite Thread Sealer lately?

[Lawrence Nitz]

HI!
Last month the setscrew in the fan blade of my Woodcraft 3hp cyclone dust collector came out, the key fell out of the keyway and blew around in the fan housing, and the machine quit. I finally obtained the required "wedding cake" shaped key stock, cut it to length, and set the setscrew with a good coating of Locktite Thread Sealant Blue. The product is supposed to cure to touch in 20 minutes. After 7 hours mine was as wet as when it came out of the tube.

I remember the old "liquid locknut" version of the product setting up and leaving a hard puddle of red plastic everyplace it touched or oozed out.

Has anyone had recent experience with these products? I need one, and it has to work before I -put the collector back together again.

Larry Nitz

[Mike Henderson]

I've used it but my bottle is old. For the amount I use it, I have a lifetime plus supply. No problems with what I have.

If I recall, with the blue, the screw can be removed. With the red, you have to heat the item to get the screw out. I may have that backwards.

Mike

[Tom Veatch]

...If I recall, with the blue, the screw can be removed. With the red, you have to heat the item to get the screw out. I may have that backwards.


You have it right, Mike.

I've used both recently, i.e. within the last 3 months, and haven't experienced anything unexpected. What I have came in small tubes like toothpaste but much smaller.

Larry, was it mixed well within the container before you used it? Before applying, I always squish the tube back and forth several times to make sure it's well mixed. Maybe it's my imagination, but after doing that, what comes out of the tube seems to have a little heavier body than it does if I simply open the cap and squirt it on the threads.

[Jamie Cowan]

I think you're right, Mike. I remember using the red, but I don't remember why. I also remember that the tiny little tube was crazy expensive. I'll bet I still have it out in the garage, but probably last used it 10 years ago. Probably not good anymore.

[Steve Leverich]

Here's the spec sheet for blue loctite, #242

http://65.213.72.112/tds5/docs/242-EN.PDF

It's considered "temporary" or removable, but in my experience for 1/4 inch or smaller fasteners it's more like permanent.

Note that cure is anaerobic - so any that's still exposed to air won't harden the same as it does between the threads... Steve

[Kyle Kraft]

Sorry to digress, but what the heck is a "wedding cake" key? I've been in the machine repair trade for 18 years and haven't heard that one yet.

[Jacob Reverb]

Loctite only "hardens" in the absence of air. It'll never "harden" when on an exposed surface. But in a threaded joint, it sets up almost immediately.

[Tom Slupek]

You used too much. Just use enough to coat about first 1\4 of the threads of the screw. When you install the screw rest of the threads are coted and it dries fairly fast. Also I found if the tapped hole and the screw are coated with grease or oil, locktite does not dry very well. Disassemble everything, clean and put a drop of locktite on a piece of plastic, roll the screw in the locktite, do not touch with your fingers and install.

[Larry Prince]

If you used the little squeeze tube chances are the material has just separated. Knead the tube and work the contents from bottom to top for a few minutes then try it again. I had the same problem several months back.

[Mike Henderson]

Loctite only "hardens" in the absence of air. It'll never "harden" when on an exposed surface. But in a threaded joint, it sets up almost immediately.
Interesting. Does anyone know what makes it harden on the threads and not harden in the container? Does it react with the metal in some way? Or does the metal act like a catalyst to the Loctite?

The data sheet just says "The product cures when confined in the absence of air between close fitting metal surfaces"

Mike

[Ken Fitzgerald]

I don't know what they use today but it was explained to me years ago when threadlocker first came out ( I mean 30 or more years ago) that locktite contained a micro-organism that died when exposed to air and swelled up in doing so. I don't know if that is true with the stuff they use today.

I use it frequently. I know that we are told that it has a shelf life....that if placed in temperatures below freezing, it loses it's characterics.

There are different types of thread locker for different uses....some for temporary or small thread use...some for permanent as in you'll need your grinder to get that bolt out....and even some made for use in situations where hydraulic oils are involved. I have used all the ones I've mentioned.

The "red" stuff creates a more lasting bond that the "blue" stuff and the gray stuff....well break out your grinder. This is all based on my personal professional experience and has no scietific evidence or proof.:)

[Tom Veatch]

Does anyone know what makes it harden on the threads and not harden in the container? ...

Don't claim to know why, and hopefully someone who does will chime in, but perhaps it's something similar to the curing of CA glues.

I recall reading that the chemistry of CA glues is such that it tends to (polymerize, harden, whatever) when spread in a thin layer and that the cure time increases dramatically with thicker layers. Something to do with the way the molecules interact. Experimentally, I've found that to be true, but don't understand why. Don't know for sure, but I suspect that a similar process is working here.

[Scott Velie]

I think Larry has it right. Give the tube a good shake.

By the way If you don't want it to EVER come out use the green (bearing and sleeve retainer).

[Rusty Elam]

I would presume a "wedding cake key" is a Woodruff key?

[Dale Lesak]

Mike, remember a long time ago that they had a special container the would let air in and keep it in a liquid state. couldn't by a big bottle and put it into smaller containers. (This was a USN tech bulletin about 30 years ago)

[Chris Matus]

Interesting. Does anyone know what makes it harden on the threads and not harden in the container? Does it react with the metal in some way? Or does the metal act like a catalyst to the Loctite?

The data sheet just says "The product cures when confined in the absence of air between close fitting metal surfaces"

Mike

Loctite, which is a brand name not a product btw, is an anaerobic compound that cures in the absence of air. This is why it is sold in bottles and tubes that are usually only partially full to allow for enough air to keep the product from curing.

[Greg Karol]

Sorry to digress, but what the heck is a "wedding cake" key? I've been in the machine repair trade for 18 years and haven't heard that one yet.


I think he means a step key. http://www.mcmaster.com/catalog/114/gfx/small/92271ac2s.gif

[Lawrence Nitz]

Thanks, Greg for naming the step key. When I needed the name, it was not at my fingertips.

I will be chasing down the folks at Loctite products to determine how now to clean unhardened thread locker out of grooves and off surfaces, so I can start over, perhaps with the red product, or another brand.

[Lee Schierer]

Thanks, Greg for naming the step key. When I needed the name, it was not at my fingertips.

I will be chasing down the folks at Loctite products to determine how now to clean unhardened thread locker out of grooves and off surfaces, so I can start over, perhaps with the red product, or another brand.

Loctite is an anaerobic curing material, but also requires iron to cure. Some plating, aluminum and stainless will not allow the loctite to cure without a primer. Look on your container it should say what primer to use Primer N and P are the most common. You can wipe off the excess material and spray on the primer then reapply the loctite. Any material left exposed to air will not cure. The primer will also speed up the cure in most cases.

Here's another fact about loctite that isn't well known. Most of their thread lock material will degrade at about 250-300 degrees to the point where they will get soft and can be loosend. Using the higher strength (red) loctite is not always a permanent solution. You can heat set screws with a soldering iron and get them out even if the red loctite has been used.