Myth vs Reality: Does Loctite Blue damage Lexan?

Does Loctite Blue really damage Lexan? Let’s find out!

I think we all agree that Lexan is strong stuff. However, let’s take a moment to show just how strong it is. Take a look at this image from this page on The caption for this image reads “Will it Break? No!”

Exhibit A

Next to the image is this quote from Jim, our generous host:

Strong stuff indeed. I think we’d all agree that Jim is a credible witness for this subject matter, so let’s accept that Lexan can be bent with a great deal of force without breaking.

The Experiment

For the experiment, I took a piece of 1/8 inch thick black Lexan, 4.5 inches long by 1.5 inches wide, and applied a layer of Loctite Blue along the center. This lexan had been random-orbit sanded to give it the nice smooth scratch-resistant satin finish that is very popular. I then set the Lexan on a shelf.

After five days, I picked up the piece of Lexan and decided it was time to test it. At first I gave it just a little bend with not much force at all. I heard a cracking sound. Interesting.

I then applied more force, and … SNAP! The piece of Lexan broke in not one, but two places, and the center piece went flying across the room. Look out!

Exhibit B

The putfile site scaled down the image, so you can’t see it that well, but there is a noticable crazing pattern (like you would see on glazed pottery) where the Loctite was applied. And in case you are thinking it, no, the random-orbit sanding does not create a pattern like this.

The Verdict

Loctite Blue damages Lexan.

PS. Yes, I changed my login name to something more anonymous. :wink:

Locktite can do that to many types of plastic. It’s a chemical reaction.

Red, the permanent stuff, is even worse. And Locktite does serious damage to Carbon fiber. More specifically, to the resins commonly used to make sandwiched carbon fiber sheet. It will crystallize and make the carbon very brittle.

It can have the same effect on certain densities of ABS and Polypropylene.
Not that there is any reason to use locktite on plastic anyways, but if you have to use a bolt through it, and want to locktite the threads, just use a locknut. And when you apply locktite, there shouldn’t be any excess puddling around the bolt anyways. Rubbing just enough on that you can barely see the color in between the threads is enough. There’s no need for a large drop on it.

maybe it something that the orbital sanding had done to it :question:

Nice experiment dude - thanks for the info

Thank you for the kind words, and the GE quote. :slight_smile: They make Lexan, so that’s as official as it gets.

I finally know for sure :laughing:

I worked at a place that made electronic flash units and we had one customer that repeatedly damaged the equipment and always took it apart to see what happened before sending it in, obviously making it very difficult for us to see what happened. The case was made from ABS but all the screws were in brass inserts. We decided to add some red loctite after this repair and dropped it off at shipping at the end of the day all nicely packed in the box…

The next morning there were circuit boards and black crumbs in the box, the vapors ate the entire housing. :rofl: