Author Topic: Bluish substance  (Read 4843 times)

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Offline tchicago

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Bluish substance
« on: April 12, 2015, 03:27:58 am »
Hi, All,

when you take apart a laptop or other portable device, you notice that the screws have had some bluish substance added to their thread. As I understand, this is to fix the screw in place and prevent unscrewing due to vibration and other periodic mechanical processes.
Is it recommended to reapply the a fresh drop of this substance when reassembling the device? If so, how is it called and where one would get it?
 

Offline Dragon88

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Re: Bluish substance
« Reply #1 on: April 12, 2015, 03:42:30 am »
It's called Loctite. You can find it locally, try the hardware store. Wal-Mart sells an off brand that works ok.

There are also different grades. Stick with the blue or a lower strength grade. Red is a little too serious for most applications.
 

Offline radioFlash

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Re: Bluish substance
« Reply #2 on: April 12, 2015, 03:42:36 am »
It's called thread locker. There are different varieties. The blue kind is intended to be removable. Other varieties are intended to be permanent. You can find it in a hardware store or auto parts shop. It's probably a good idea to apply it, but I don't usually bother unless I expect a lot of vibration.
 

Offline peter.mitchell

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Re: Bluish substance
« Reply #3 on: April 12, 2015, 03:44:32 am »
semi-permanent/removable thread-locking fluid, also known as threadlocker, or "blue locktite". the removeable stuff is recommended, if you use the permanent stuff, you'll be unlikely to remove the screw, ever.
whether you reapply it or not is up to you, the majority of computer/notebook repair stores don't bother.
 

Online Shock

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Re: Bluish substance
« Reply #4 on: April 12, 2015, 03:48:37 am »
Loctite or thread lock. Depends if it's "just in case" application or something you know will vibrate lose. Anything that is likely to receive mechanical vibration or leave a screw rattling around inside your equipment is most important. I've used nail polish or a seriously tiny amount of super glue for similar uses.

http://en.wikipedia.org/wiki/Thread-locking_fluid

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Offline Ian.M

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Re: Bluish substance
« Reply #5 on: April 12, 2015, 04:23:20 am »
Caution: The solvents in many Loctite and similar threadlocking fluids attack common plastics including ABS and other Styrene copolymers, Polycarbonate, Nylon, and many others.  Effects range from softening and distortion, to embrittlement, to rapid crazing leading to disintegration under slight loads.

Unless you have checked with the manufacturer that the specific threadlocker you are using is safe for the type of plastic round the screw you are applying it to, applying fresh threadlocker could be a *VERY* *EXPENSIVE* mistake.
 

Online tautech

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Re: Bluish substance
« Reply #6 on: April 12, 2015, 07:31:55 am »
In my experience you won't have to add additional thread locker after a repair.
Some srcews come new with this locker applied, it is not generally a "setting" product, it just reduces the chance of a screw coming loose.
You should notice a slight resistance when refitting these screws, more noticeable with a machine screw than a self tapper.
Think of it as more of an adhesion than a lock. Commonly seen in blue, but sometimes red.

Loctite's generally do set and form a bond that must be broken for screw/nut/bolt/stud removal.
Available in many colours and strengths.

Avid Rabid Hobbyist
 

Offline sdg

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Re: Bluish substance
« Reply #7 on: April 12, 2015, 05:08:28 pm »
Hi, All,

when you take apart a laptop or other portable device, you notice that the screws have had some bluish substance added to their thread. As I understand, this is to fix the screw in place and prevent unscrewing due to vibration and other periodic mechanical processes.
Is it recommended to reapply the a fresh drop of this substance when reassembling the device? If so, how is it called and where one would get it?

Tuflok. You can safely reuse the screws.
--
 -sdg
 

Offline Guni

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Re: Bluish substance
« Reply #8 on: April 12, 2015, 06:25:18 pm »
Loctite 243 (blue)
http://www.henkelna.com/product-search-1554.htm?nodeid=8797952212993

You can find also Loctite 243 under diferent brand/name from Henkel Group. For example Patex.

Don't use other type of Loctite without checking description. Some type as mentioned above are permanent 

Problem is that on most screws is not a true threadlocker but fake - blue color oil paint only.

 
 

Offline electr_peter

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Re: Bluish substance
« Reply #9 on: April 12, 2015, 09:15:00 pm »
Use thread locker only on metal to metal contact (metal screws to metal inserts/nuts or similar). Using it with non metals is both not helpful and damaging to materials.
 

Offline Ian.M

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Re: Bluish substance
« Reply #10 on: April 12, 2015, 09:53:00 pm »
That's ALL metal to metal contact at that fastening.  If any of the threadlocker gets squeezed out during assembly and reaches a plastic part, if the part is made from a themoplastic, its likely to end up with about as much remaining strength as peanut brittle in the area affected. 

Loctite 243 is sold for metal to metal use only.  I certainly wouldn't use it anywhere near any ABS parts of a laptop case. 

Just about the only place where threadlocker might be beneficial is for screws holding a metal hinge to a metal frame or reinforcing plate.
« Last Edit: April 12, 2015, 11:52:13 pm by Ian.M »
 

Offline rolycat

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Re: Bluish substance
« Reply #11 on: April 12, 2015, 11:02:33 pm »
semi-permanent/removable thread-locking fluid, also known as threadlocker, or "blue locktite". the removeable stuff is recommended, if you use the permanent stuff, you'll be unlikely to remove the screw, ever.
The Loctite manufacturer's website has a helpful video showing how to remove bolts fixed with red 'permanent' threadlock. All you need to do is apply a blowtorch flame "for a couple of minutes". This may void the warranty on your laptop...
 

Offline SeanB

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Re: Bluish substance
« Reply #12 on: April 13, 2015, 08:41:28 pm »
Use Loctite 603, as it works to hold even in an oil bath. I used it to hold a gear on the shaft when I could not get the right gear on the discontinued gearbox from SEW, and the only gears they had that were the right match were for the upgraded box with a 2mm larger idler shaft. A bit of work with some tinsnips, a piece of convenient galvanised steel, a file and a hammer and the loctite 603 and that gear was a permanent part of the shaft, swimming in the Gengear 320. Was a little noisy, but with the rest of the machine being so much louder you could not hear it. I really wanted to get rid of that Varimot, so the next upgrade was the new end bell, a variable speed drive and half a motor.
 

Offline m100

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Re: Bluish substance
« Reply #13 on: April 13, 2015, 09:57:57 pm »
The Loctite manufacturer's website has a helpful video showing how to remove bolts fixed with red 'permanent' threadlock. All you need to do is apply a blowtorch flame "for a couple of minutes". This may void the warranty on your laptop...

Loctite haven't realised that applying large quantities of localised heat to small screws is what a soldering iron is useful for.  They are also useful for destroying epoxy resin joints too.

 


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