Threadlocker (Loctite) Guide - Wiki

sleepless · May 13, 2021, 5:14pm

There’s a few threads on this, but this question gets asked constantly by new and experienced builders. This wiki should be a one stop shop for those questions. Please update as you see fit.

Editor’s request: Stop referring to threadlocker by colors. As you can see below, there are many grades, each with very specific properties and applications, in many different bottle colors and liquid colors. There’s hundreds more that aren’t listed here. Colors are vague and spread confusion more than help.

SELECTION GUIDE

Application	Esk8 Use	Part	Strength	Color	Features	Size	Disassembly	Cure Time	Op Temp
THREADLOCKING (screws)	n/a	Loctite 222	Low	Purple	Easily removable with normal tools		Easy	24 hrs	150 C (300 F)
	Use 243 instead. Or, clean parts to remove all oils & dirt. Must be applied before assembly.	Loctite 242	Medium	Blue	Disassembly with normal tools		Normal	24 hrs	180 C (360 F)
	General purpose medium, truck fasteners & nuts, enclosure fasteners. Must be applied before assembly.	Loctite 243	Medium	Blue	242 new formulation, with improved oil/dirt resistance		Normal	24 hrs	180 C (360 F)
	Must be applied before assembly.	Loctite 262	High	Red	Disassembly with direct heat		Heat, 250C	24 hrs	180 C (360 F)
	General purpose high, motor mount fasteners. Must be applied before assembly.	Loctite 263	High	Red	262 new formulation, with improved oil/dirt resistance		Heat, 250C	24 hrs	180 C (360 F)
	General purpose, motor bolts, mount bolts, enclosure bolts, hanger axles. Can be applied before OR AFTER assembly.	Loctite 290	Medium/High	Green	Wicking, for preassembled fasteners		Normal	24 hrs	150 C (300 F)

RETAINING (shafts)	Must be applied before assembly.	Loctite 638	High	Green	High viscosity, use on larger gaps approaching 0.25mm	0.25mm gap	Heat, 250C	24 hrs	180 C (360 F)
	Pulleys/gears/sprockets/keys onto motor shafts. Must be applied before assembly.	Loctite 648	High	Green	Low viscosity, press/close fit cylindrical parts (100% cure in 7 days)	0.15mm gap	Heat, 250C	24 hrs	175C (350F)
	Must be applied before assembly.	Loctite 680	High	Green	Low viscotiy, loose fitting parts, slip fit. Best resistance to dynamic, axial, radial loads. (100% cure in 7 days)	0.2mm gap	Heat, 250C	24 hrs	150 C (300 F)

Bolded items are recommended to have in your toolbox

HOW TO APPLY THREADLOCKER CORRECTLY

Common Application Mistakes

Failing to clean the fastener and the threaded hole
Dirt, grease, and oil residue are all enemies of threadlockers. To get the full cure and full holding power of your threadlocker, the male and female threads need to be completely clean and dry. Don’t shortcut this step.
Using too much threadlocker:
Threadlockers only need to be applied to the first few threads on a fastener. Tightening the fastener will spread the threadlocker evenly. Using too much threadlocker can cause excess to spill out and migrate to unwanted areas.
Not waiting for the proper cure time:
Threadlockers provide excellent holding power - but only after they’ve had time to cure. Typically, threadlockers achieve ‘fixture strength’ in 20 minutes and fully cure in 24 hours. Fixture strength means it’s OK to put your assembly back in service, but a full cure is when you’re getting the full holding power of the threadlocker.

DISASSEMBLY & CLEANING

[credit: @rusins ]

To remove pulleys, sprockets, and gears from motor shafts:
Use a pulley remover tool (aka gear puller). They apply way more force than you could by hammering at them.

A wiper arm puller like the Lisle 54150 has thin arms to get into especially tight spacers.
To clean threadlocker off fasteners:
Acetone appears to dissolve blue and red threadlockers quite well. Just use a paper towel and your nails to scrape it off, should work. A wire brush can also be helpful.

image1404×1084 133 KB
To disassemble fasteners with red (high strength) threadlocker:
You need a heat gun. Once you heat it to a certain point and turn the bolt a little bit, it should be possible to then unscrew it completely.
To disassemble fasteners with green (high strength) threadlocker:
You need a butane torch. Even then it might not want to come off. All I can say to you is: good luck

PLACES TO PURCHASE

Links and prices as of May 2021
Google shopping is your friend, but the above links are a good start. It will take you forever to finish a small bottle, let alone the 50ml bottles.

REFERENCES - Charts

[credit: @PixelatedPolyeurthan and @frankthedragon]

REFERENCES - Forum Threads

REFERENCES - Henkel Loctite Corp information

sleepless · May 13, 2021, 6:03pm

Great addition. I personally don’t trust Permatex with safety related adhesion after some personal failures, but to be fair, I was probably using the wrong grade.

Also super available at any Autozone, NAPA, O’Reilly, etc

EarlLemonGrab · May 14, 2021, 1:18am

Where is the best place to buy Loctite online?

joshoujoe · May 14, 2021, 1:39am

unless you let the bottle open on accident or spill it like a dumdum otherwise it’s true

BillGordon · May 14, 2021, 12:46pm

Nice resource! About time someone sorted this issue.

rusins · May 14, 2021, 3:03pm

When taking pulleys / gears off motors
Use a pulley remover tool. They apply way more force than you could by hammering at them.

When cleaning threadlocker off bolts:
Acetone appears to dissolve blue and red threadlockers quite well. Just use a paper towel and your nails to scrape it off, should work.

When taking apart bolts with red threadlocker
You need a heat gun. Once you heat it to a certain point and turn the bolt a little bit, it should be possible to then unscrew it completely.

When taking apart parts with green threadlocker
You need a butane torch. Even then it might not want to come off. All I can say to you is: good luck

PixelatedPolyeurthan · May 14, 2021, 5:17pm

@sleepless edited the main post

mr.shiteside · December 14, 2022, 4:19pm

I regularly come back to this so thanks @sleepless

One question for the class about choosing; does motor mount fasteners apply to grub screws locating the mount on the hanger? In my head any screw holding a specific position in a slot (like those motor mounts that you set the angle within a long slot rather than discrete round holes at angle increments) probably need very high torque so any vibration loosening is upper case Bad. The fastener’s torque’s friction is resisting the whole torque of the motor

But ATM I’m about to screw down Idea mounts on BN hangers and the bigass grub screws are perpendicular to the force, I know they still get a lot vibration but I’m curious if I need to bother with high strength threadlocker?

I’ve got some 270 (high strength, 300°C to remove) as well as what I think is 2400? The number on the label has worn off, but it’s 4 digits, medium strength, blue threadlocker so 2400 is the only one that fits that bill. I’m fairly anxious about commitment but trying to get over that, my issue is I don’t have a torch if this goes tits up. Should I just bite the bullet and 270 it or would 2400 be grand? Also I’ve been prepping the area with acetone nail polish remover and still struggling to get it spotless, maybe it’s just not the right stuff for the job but I’m still seeing very small amounts of gunk from old threadlocker on there

Dinnye · December 23, 2022, 5:54pm

You do. My Idea mounts have been coming loose frequently with 243 while I was using them on onsra 115s or thanes. Maybe with pneumatics 243 would be fine

mr.shiteside · December 23, 2022, 6:40pm

Ah shit, thanks anyway. I put 2400 on but the next time I take it apart I’ll clean it out and go for the more permanent one

glyphiks · December 23, 2022, 9:49pm

I find that the problem with that mounting method is that the mounts generally always come loose due to the grubs eating into the hanger. No amount of loctite can prevent that, so using one that is easy enough to break allows you to nip them up tighter without having to go crazy with heat.

mr.shiteside · December 23, 2022, 9:53pm

Yeah I’ve had some issues with that in the past too, especially when I didn’t tighten them properly so they moved a bit and wore themselves a groove even faster. Is the alternative just tension? I can’t remember if older BN mounts are like that

glyphiks · December 23, 2022, 9:55pm

In my experience, two piece clamps hold the strongest.

The latest boardnamics mounts all use a one piece clamp that bolts together and uses tension, but IMO it’s nowhere near as good as the two piece.

IMG_1351-scaled

mr.shiteside · December 23, 2022, 10:07pm

Ah cheers yeah I hadn’t really thought about the difference between 2-piece and 1-piece tension ones. Might have a look if I get hassle from these ideas, but they’re so pretty

Egtscs · February 11, 2023, 7:38am

I know exactly what you’re talking about, I have the BN mounts and I absolutely agree, the 1 piece works but I have to use a combination wrench as a breaker bar on the Allen key for extra leverage to even get it somewhat snug on the hanger

glyphiks · February 11, 2023, 8:02am

Yeah dude, 2 piece is superior

haven · April 17, 2023, 8:58am

This thread indicates that loctite 648 is better than 638 for smaller press fit gaps… is there a source for that info?

For reference, I’m deciding which loctite formula to use to secure a BN motor pinion, so the gap is obv quite small. Also going to use a shaft collar for extra retention strength. Just want to make sure I’m doing everything I can to prevent a failure.

AI says the opposite is true, and 638 is better for the smaller gaps

ChatGPT on 638vs648:

“In summary, the main difference between Loctite 638 and Loctite 648 is their gap-filling capability. Loctite 638 is best for smaller gaps, while Loctite 648 can fill larger gaps. It is important to choose the correct adhesive based on the specific application requirements to ensure optimal bonding performance.”

glyphiks · April 17, 2023, 9:12am

648 be thiccer.

haven · April 17, 2023, 9:13am

yeah I guess that’s it, which would mean it’s better for larger gaps, and apparently not as ideal for the smaller gaps/press fits

maybe thread could use an update? or maybe it’s not even worth it, they can probably be used interchangeably tbh

glyphiks · April 17, 2023, 9:45am

I’ve done so with zero discernable difference