Jim Lux wrote:
>Having found this out the hard way... the folks that make Loc-tite only
>have 3 or 4 colors (red, green, blue, purple, and maybe orange or
>yellow) for dozens of different products, not to mention that other
>manufacturers of these wonderful materials use different color codes.
>
>But, there are basically three "permanence" grades:
>lock forever, use heat to remove
I believe this range is colored red.
>locks fairly permanently, but you can wrench remove it
Green
>locks less permanently, basically keeps it from vibrating out, pretty
>easy to break loose
>
Blue. There's also an even weaker pink range for use with very tiny
screws.
>And, there are three application methods (depending on the stuff)
>1) Apply to threads, let dry, install (you can actually buy
>bolts/screws with it preapplied!)
>2) Apply to threads, install while wet, cures in place
>3) Install fastener, apply stuff, wicks in by capillary action after
>assembly (real handy for "staking" after assembly of a complex assembly)
>
>That gives you 9 possibilities already, and there's actually a lot
>more.
You're right, Jim, I should have been more specific. The grade I use
routinely for antenna work is the blue Loctite 242. In Loctite's own
words:
"LOCTITE 242 is designed for the locking and sealing of
threaded fasteners which require normal disassembly with
standard hand tools. The product cures when confined in the
absence of air between close fitting metal surfaces and
prevents loosening and leakage from shock and vibration.
Particularly suitable for applications on less active substrates
such as stainless steel and plated surfaces, where
disassembly with hand tools is required for servicing. The
thixotropic nature of LOCTITE 242 reduces the migration of
liquid product after application to the substrate."
This grade is one that you apply to the thread and install while wet,
and then it cures in about 24 hours. It will keep normally tightened
nuts or screws from vibrating loose in the long term, while also sealing
the threads against corrosion. Disassembly with hand tools requires
about the same torque as nyloc nuts.
Sorry, I can't remember exactly what grade of "red Loctite" was used for
locking the stainless steel studs into the old Ham-M bell housing... but
30 years later, those studs are still firm.
--
73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek
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