Which Loctite?

Hello again, another beginner question fuelled by confusion and a desperate attempt to stop spending money.

The choice of Loctite grades is bewildering. If I was to buy just one, primarily to diswade nuts and bolts from unscrewing which do I go for?

Edited By Paul McDonough on 08/05/2023 10:41:04

Yes it is, but remember these are specialist products widely used in industry for a miriad of different tasks. For the very general use you seem to be looking for just choose a basic thread lock. See any supplier website* for simple suggestions.

Also note there are numerous generic versions which are often cheaper and do the job. Don't get bogged down with data specs or you'll get thoroughly confused.

*e.g. search for 'adhesives' on the ARC Eurotrade website

Edited By Mike Hurley on 08/05/2023 11:18:02

IF you mean real Loctite then their all costly, but there are other makes. For your use it's got to be med strength ! There are so many because there are so many different applications, if you really don't want it to undo then high strength ! Noel.

You need their threadlocker, not their retaining compound. EG Loctite 242 or 243. It is blue in colour. Made for keeping vibrating nuts and bolts together. It keeps Harley Davidsons in one piece so is pretty good.

Their red threadlocker is a more permanent bond and you will need a propane torch to get it undone. Ditto their various retaining compounds, made to cement bearings etc permanently in place.

I often use a dab of ordinary superglue, but not when doing proper engineering.

Proper engineering applies when:

• Safety matters (use the correct item on motorbike brakes!)
• Reliability matters (when bits falling off cause unwanted downtime)
• The environment is adverse - heat, wet, vibration etc,
• Disassembly as normal operation, or for maintenance is important.

Engineers look for a Loctite type products that meet a combination of requirements, like being heat resistant to 180°C, resists moderate vibration, but is removable with a spanner. Different product used when the fastener is cold, subject to heavy vibration, and dismantling unlikely, or done specially.

For my purposes superglue is fine: low temperature, ordinary reliability, not safety critical and special dismantling not a problem.

Dave

Paul I know what you mean, Loctite do a massive range for all types of industries.

However for what its worth I use 542 thread sealant and 603 retaining compound for wheels, bearings etc.

For thread sealant you want something that will stop a fastening shaking loose but that can still be undone when needed. The retainer can be released with a blow torch, about 250 deg.C is needed I think.

Loctite is probably more expensive than some others but it might be of interest if you can find a supplier with 'out of date' stock. My local ME supplier sold me some, he said he is happy to use it for ME work, the expiry date is of course critical to industries such as aerospce and others.

Bill D.

Loctite 263 is the first choice for threads from 1/4", 6mm upwards. Smaller threads might break before being unscrewed and would require a weaker product such as 243 and 222 for the smallest threads. 290 is like penetrating oil and can be used on fasteners after they have been assembled, which can be handy. 270 came to mind first, but it seems to have been superceeded.

Edited By old mart on 08/05/2023 14:46:41

Edited By old mart on 08/05/2023 14:50:10

Oh wow, I didn’t realise some were permanent, not withstanding application of copious amounts of heat and it didn’t occur to me that there were alternative brands either, I have lived a sheltered life brainwashed by brand marketing. I shall have a search for ‘Medium’ strength.

thanks for your comments Paul

Edited By Paul McDonough on 08/05/2023 18:39:42

Hi

if you only want to stop threads slipping I use nail varnish (it's free when the colour goes out of date)

George

Medium strength would be 243. If you google loctite, there is a lot of information available.

263 is the red high-strength permanent threadlocker. Don;t use it on anything you want to pull apart unless you can hit it with a blowtorch first. Do use it on things like motorcycle engine sprocket nuts or clutch centre nuts that are high-shock load and semi-permanent (and can be subjected to heat for disassembly.). Don't use it on ordinary nuts and bolts such as motorcycle mudguard stays, footpegs, engine mount bolts, brake caliper bolts etc etc. .

243 is blue medium strength threadlocker and works fine on all sized threads to stop them coming undone from vibration. Holds the nuts on but can be undone with a spanner and a bit of grunt.

222 is the low-strength thread locker, purple colour, used mostly in small instrument and electrical threads on things like adjuster screws in Lucas voltage regulators etc Suitable for model work on small screws of 2 or 3mm diameter.

Other cheaper brands seem to stick with this colour coding: blue for general threadlocker, red for high-strength permanent threadlocker or retaining compound.

Edited By Hopper on 09/05/2023 04:41:23

Edited By Hopper on 09/05/2023 05:05:46

lots of cheep "loctite" in the bay of fleece its fake. a problem to the aerospace industry but properly OK for ME

And others are genuine but out of date. Still seems to work ok but unsellable by authorised Loctite suppliers.

Lots of different versions of Loctite is just clever marketing to sell more of it. As Hopper says, you just need permanent, medium and soft.

Similar money making policy putting on dates for expiry - if it is still runny it will still work.

Lots of different Loctites is exactly what industry requires for their very specific needs. Hobbyists are only a fraction of a percent of their sales and do not count.

Thank you everyone for your helpful explanations, seems like ‘blue is the colour’

As nobody else has mentioned it, can I suggest another option, Loctite 248

It's another general purpose medium strength thread locker but comes in stick form rather than liquid. For me the advantage is not having to deal with drips!

Graham

Here is a page from the Loctite book that might be of interest.

Peter

Thank you. I have found a copy cat product on Amazon at reasonable cost. Its blue so the colour is right!

Only time will tell if it keeps things together.

As we say in motorcycle world: Only the weak parts fall off, leaving the parent machine stronger.

Never had blue threadlocker fail on general bike parts yet though.