Robert,
In the interest of not continually writing the same story over and over, I just refer to three notes about hinges for aluminium battens.
In 1991 I made a set of hinges for a 32m2 sail (Malena), shown in NL 24, p.22. This was used for coastal sailing and never gave any structural problems.
In Magazine 50, p.15 Lex Hodkinson shows the hinges he used on his Passepatu for many years.
In Magazine 54, p.33 I suggest another set of hinges, a sort of combination of my 1991 model and Lex’s model.
Lex’s and my last cardboard model share the advantage that you can replace the hinge piece with a longer or shorter one, to get less or more camber, but without altering the total length of the batten (unlike in Malena’s 1991 model). Still, I would rather use my last (“outside”) model where the hinge is stuck inside the hinge part and note vice versa (as in Lex’s model). I think the outside hinge will be the stronger of the two. A possible disadvantage with the outside hinge may be that it is too wide for the batten pockets, if your sails are fitted with that. Luckily, the pockets on Malena’s sail were just roomy enough to take the 40mm hinges.
Hope this makes sense.
Arne