Um, that sort of doesn't make sense! Do the inserts need to be fixed in the titanium or not? And why would you bond for lubrication and fixing it stronger. Am I missing something?

Chris,

638 Loctite on a sliding fit would be fine, I think.

MichaelG.

Edited By Michael Gilligan on 19/07/2015 16:36:25

Nice looking forks, Chris

**LINK** for the convenience of others.

MichaelG.

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P.S. … Useful document, here

 It may be worth using an activator … Probably best to try a test piece first.

Titanium is considered inert, and aluminium only weakly active, so 638 may cure more slowly than usual. … It does no harm to the joint strength though.

Edited By Michael Gilligan on 19/07/2015 17:08:47

.

Yes … Shouldn't be any problem,

and [pace, Neil] it will avoid the 'galling' that you might get with anything tighter.

MichaelG.

The dropouts were bonded in you need a bond line thickness of maybe. 5 to. 9 for the adhesive we use Dp420 from 3m though other adhesives will give you similar properties we use 30Mpa as a minimum loctite is generally lower (low 20s) by the time you have taken material tests and type into account all materials don’t achieve the highest value stated on the manufacturers literature however, often we achieve 37-48 mpa dependant on preparation, the tops where the crown clamps iirc used to crimp, titanium fork legs are substantially more flexible than the cro mo or mangmoly pace used,

Edited By mike mcdermid on 20/07/2015 00:07:42

Edited By mike mcdermid on 20/07/2015 00:08:53

Edited By mike mcdermid on 20/07/2015 00:09:26

Michael don’t be daft man I just worked in F1 right from the days where bonding flexures into wishbones was the norm, I’m a composites engineering type but made carbon titanium and aluminium bikes for some companies, it’s like having a mastermind specialist subject, sadly mines glue, the strongest ones come from Hexel 3m is a pretty good all rounder but similar to the araldite 2014 and permabond, it’s a generic mid strength toughened epoxy

Mike,

I would be grateful for the benefit of your experience [and I suspect that others would, too]:

Although Epoxy resins are excellent in many respects, I have seen a number of joint failures on Aluminium alloys; and these were [I believe] typically down to inadequate surface preparation. … We had great success with Araldite 2002, on glass/epoxy [presumably you remember Ciba Geigy 'F-Board'], but results on Aluminium alloys were much less predictable.

Where the joint design permitted; we preferred to use Loctite 638, and found this to be 100% reliable [even with very rudimentary surface preparation] … and this was why I recommended it to Chris.

Now: Your experience is much more sophisticated than mine, so the question is: How do you prepare the Aluminium alloy surface, to ensure good bonding? … Chris's forks project would be an ideal example for a 'Tutorial'.

Many Thanks

MichaelG.