Threadlock for titanium?

[chriscross1966]

Hi folks... bit of an odd one, but I've got issues with titanium screws in titanium components undoing themselves despite using decent (Loctite 222) threadlock. Googling got me dreadful signal to noise ratio, and a lot of ignorant woo as well as well thought out engineering opinions that were diametrically opposed to each other.... oh and a lot of racist crap about Far-Eastern fasteners, but I digress...

ANyway, I need to solve this as one of the fasteners affected is a pivot bolt on the rear triangle of a Brompton.... I've got an after-market Ti kit in there, mostly because the standard steel replacements is a dealer-fitment only part from Brompton.... If push comes to shove I can make pivots at home (I have a lathe, that pivot is a 3/8 bit of tool steel with a threaded hole in each end), but the Ti kits are cheap enough that I'd rather spend my time on other things....

 

[sight-pin]

How about using a Nyloc screw, Not sure if they come in titanium though?
This type of screw i mean https://www.lancasterfastener.com/nylok-tuf-lock-blue-patch-fasteners

 

[gbb]

Simplest option, buy some medium or high stregnth threadlock. 222 is low strength of course.

 

[Profpointy]

Simplest option, buy some medium or high stregnth threadlock. 222 is low strength of course.

Umm is that wise? , isn't high strenght threadlock the stuff that won't undo unless you heat it up with an acetelyne torch ?

 

[Profpointy]

I've never had to use an acetelyne torch on threadlock. Once disassembled you can use heat to get rid of the threadlock but you don't have to.

I thought I'd read that somewhere but might be wrong. That said the super strong grades are I believe, intended never ever to come undone, rather than for avoiding shaking loose

 

[Ajax Bay]

I use medium threadlock routinely for (eg) chainring bolts, cleat bolts, seatpost bolt. Never had a problem removing: little 'click' as they release.
'Lively' discussion on this CC thread: How-to-stop-bolts-from-loosening

 

[Tangoup51]

I thought I'd read that somewhere but might be wrong. That said the super strong grades are I believe, intended never ever to come undone, rather than for avoiding shaking loose

Depends where you're buying. High-strength thread lockers don't seal the bolt, they're just highly vibration resistant. That's just from my shopping experience.

 

[twentysix by twentyfive]

Split pin?

 

[keithmac]

Worth a look.

 

[keithmac]

If you plaster the fixing in high strength then you'll probably round head off trying to remove it again, just a drop should do.

Personally I prefer steel fasteners.

 

[raleighnut]

There is no need to use a 'gas axe' on a bolt to break threadlock, a soldering iron held on the head of the bolt for a minute or so gets it plenty warm enough and as long as you don't overdo it won't damage paintwork.

 

[Randy Butternubs]

There is no need to use a 'gas axe' on a bolt to break threadlock, a soldering iron held on the head of the bolt for a minute or so gets it plenty warm enough and as long as you don't overdo it won't damage paintwork.

This is an excellent tip I'd never considered. I'm guessing it would help to free seized screws too.

All my locitite is "medium strength" and it's is no trouble to remove so I second the recommendations to change up.

 

[chriscross1966]

Split pin?

Not practical in the space unfortunately...

 

[Ajax Bay]

I've got issues with titanium screws in titanium components undoing themselves despite using decent (Loctite 222) threadlock.

See my post (just now, thanks @woodenspoons ) on this CC thread: How-to-stop-bolts-from-loosening
Wiki: "Because thread locking adhesives typically rely on the electrochemical activity of a metal substrate to form a bond, substrates often require thorough cleaning, and in the case of less electrochemically active metals such as aluminium, priming"
Titanium sits right beside aluminium in the reactivity series so maybe a primer is required for your titanium components before applying threadlocker (medium at least).
Loctite.com
"Q8: Do I need to use a primer with anaerobics?
A: We recommend the use of primers such as LOCTITE 7649 & 7471 with most anaerobics where both parts are classified as "inactive" metals. These metals lack the presence of iron or copper content and thus, lack the "active" metal ions required to fully cure the product in 24 hours. These metals include plated parts, stainless steel, galvanized steel and anodized aluminum, to name a few. If, on the other hand, both or at least one part is an "active" metal, such as plain steel, brass, bronze, copper or iron, there is no need to use a primer to ensure full cure in what is typically 24 hours at room temperature."

Having had a look, it seems that priming increases the speed of 'curing' of the threadlocker, as does a warmer temperature. But use of a primer for the tiny diameter threads we are dealing with is disproportionate. Maybe, ChrisCross, use it, on clean threads in the warm and give the titanium fastenings a day to cure. Maybe these aspects have been factors in your titanium 'issues' (see quote above).

 

[chriscross1966]

See my post (just now, thanks @woodenspoons ) on this CC thread: How-to-stop-bolts-from-loosening
Wiki: "Because thread locking adhesives typically rely on the electrochemical activity of a metal substrate to form a bond, substrates often require thorough cleaning, and in the case of less electrochemically active metals such as aluminium, priming"
Titanium sits right beside aluminium in the reactivity series so maybe a primer is required for your titanium components before applying threadlocker (medium at least).
Loctite.com
"Q8: Do I need to use a primer with anaerobics?
A: We recommend the use of primers such as LOCTITE 7649 & 7471 with most anaerobics where both parts are classified as "inactive" metals. These metals lack the presence of iron or copper content and thus, lack the "active" metal ions required to fully cure the product in 24 hours. These metals include plated parts, stainless steel, galvanized steel and anodized aluminum, to name a few. If, on the other hand, both or at least one part is an "active" metal, such as plain steel, brass, bronze, copper or iron, there is no need to use a primer to ensure full cure in what is typically 24 hours at room temperature."

Having had a look, it seems that priming increases the speed of 'curing' of the threadlocker, as does a warmer temperature. But use of a primer for the tiny diameter threads we are dealing with is disproportionate. Maybe, ChrisCross, use it, on clean threads in the warm and give the titanium fastenings a day to cure. Maybe these aspects have been factors in your titanium 'issues' (see quote above).

Thanks for that Alex, I'l;l look into getting some primer.... warmth isn't an easy thing to find as I keep my house pretty cold (allotmenteer, I have a lot of stored potatoes and squashes etc...) , and the likelihood of me being able to guarantee not to ride the thing for 24 hours is pretty minimal too :-)

That is the sort of advice that was drowning in the noise when I googled...