Had an interesting meeting today

[JonnyDingDongs 158]

The company I work for gets all of its threadlocker, gasket sealant, and various other compounds from a local distributor. This company deals heavily with Loctite® (Henkel Corp) and brought one of their sales reps in to give us a little more education on the uses for their products. Mainly so we on the floor would request their new, expensive products I think..

The Loctite rep brought several things to my attention that I think are extremely important to those of us using these products.

 

Anaerobic Thermo-set Plastic

Threadlocker will not cure unless deprived of oxygen. Once inside the threads of a fastener, it will cure into a hard plastic that varies in strength based on the particular thread size you are using but the excess that drips or squeezes out will not. This is why, even hours after application, any Loctite on the surface of your workpiece will remain in a liquid state.

 

Primer

I was unaware, as I'm sure many of you are, that threadlocker requires two active metal surfaces to fully cure. "Active" being basically any metal surface that will corrode. Which means that most nuts and bolts we use on our guns will not allow the Loctite to cure!

Inactive surfaces:

• Aluminum (probably not a big deal)
  
• Stainless Steel
  
• Magnesium
  
• Zinc (anything galvanized)
  
• Black Oxide (the coating on nearly all bolts and machine screws)
  
• Cadmium
  
• Titanium
  
• and "others"
  

Fortunately, they make a spray that contains copper, among other things, which acts as a primer and allows the threadlocker to do its job. Their item number is: 38402 for a 1.75 oz bottle. Unfortunately, this is not something you can pick up at Walmart; only an authorized distributor. Looks like I need to make another trip to Fastenal...

I realize that most of you have never had an issue with Loctite failing, but if it ever does, I'd bet good money this was the culprit.

 

They are discontinuing 242 (the blue stuff)

Not all of it, don't panic. It is being replaced by 243, which is way better. 243 will cut through oil and have a higher temperature resistance. If you are getting commercial-grade stuff, this probably will not effect you, as you are at the mercy of what is on the shelf.

 

Wicking-grade Loctite (green stuff)

It's too early to tell, but I may have just found a way to keep those operating rods from wiggling and ultimately beating themselves loose. I realize that they are peened in place, but I have noticed that mine continues to get more slack in it over time. I suspect that there is enough room for the op-rod to move and thus "waller" itself out. There is a product (Loctite 290) that can wick its way into the threads and create a bond, even though the parts are already assembled. Rated at 300 degrees for operating temperature (this is my concern-may not be high enough) 90 in/lbs for breakaway force, and up to 1/2" fasteners. If anyone has experience with this, I would love some feedback.

 

Not safe on some plastics

The rep brought a sample of 1" thick acrylic that had been drilled and tapped. Threadlocker was then applied and promptly shattered the block! Evidently, Loctite is not safe for use on some thermoplastics. He said that nylon should be safe, but I would strongly caution anyone against using threadlocker in any situation that involves contact with plastic parts.

 

Machine Screws

The majority of our use is on the screws for the trigger guard and pistol grip. Most of what you can find commercially available will indicate on the package what size of fastener it is best used for. However, most of the blue stuff out there is intended for 1/4" and up. Loctite recommends 222MS (the purple stuff) for anything under 1/4".

 

Sorry for yet another ridiculously long post, but I felt it important to convey this information to you guys since our primary use for fasteners is to make things go -boom- in front of our faces.

[Deadeye 325]

good info thanks

[G O B 3,516]

Good info. Especially about the purple. I have used the green for many years, it lets you get everything assembled before using, even works on fine threads - and anything that hold tight with the constant vibration on an escalator is great stuff ( it does smell BAD , do not use in the house!). Your handguards will have flamed into charcoal long before you will see 300 degrees F on the op rod.

[Odd Man Out 1,283]

Thanks for the post -- very informative

[YOT 3,743]

Thanks from me, too. Especially about the primer.

[vulcan16 971]

We use locltite 290 green to secure bearings.

Some also use it on toolbox locks. The owner will never be able to open the box without a drill bit.

[Salmonking 149]

I've actually used black nail polish with great results. I first tried it out when I was fiddling around and put in an adjustable over-travel set screw into my trigger-guard.

 

Edited January 24, 2012 by Salmonking

[Agent Lemon 157]

Great info, thanks.

[liberty -r- death 1,445]

Posts like this are what keep me coming back. I almost never fail to learn something when I log in.

 

Thank you for the post.

[JonnyDingDongs 158]

Your handguards will have flamed into charcoal long before you will see 300 degrees F on the op rod.

 

I wasn't sure just how hot it gets in that gas tube, but I've applied it to my Op-rod now, so we'll all find out together.

 

Posts like this are what keep me coming back. I almost never fail to learn something when I log in.

 

Thank you for the post.

 

Aw shucks, I'm just doin' my thing.

[JonnyDingDongs 158]