Tufnol for springs

Strictly speaking, "Tufnol for dummy spring leaves".
A Google search has thrown up only one reference for pre-forming Tufnol
strip for use as (effectively) inert padding between the working steel
(or in my case hard temper P/B) leaves for model locomotive springs. The
suggestion is that heating the Tufnol to approximately 150 deg. C.
should produce the necessary permanent set. Has anyone else had direct
experience of this. My material, both P/B and Tufnol, is 1/16" x 5/8"
strip. Calculations (formulae from 'Tubal Cain's' book) indicate that a
mere 2 bronze leaves would not be over stressed with 40lb per wheel and
that more than more than 3 would be likely to be much too stiff.
Experiments with cold bending shows that the Tufnol is remarkably
forgiving in that it will revert to almost straight even if after being
deformed to a circle of diameter about 12". 12" would seem to be a
useful target diameter for my purposes.
While making my search I was reminded that somewhere I have read of soft
aluminium being used for the same purpose (dummy spring leaves). Any
comments on this will also be gratefully received.
Reply to
Mike H
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Can't give you an exact temperature but Tufnol bends fine when hot and retains its shape after cooling.
I've rescued overheated malformed high power loudspeaker suspensions this way. Simply play a hot air gun on it until it becomes pliable and takes a permanent set.
Reply to
Tufnol is a British trade name for a product known genericly as phenolic. As a rule, it's cloth or paper impregnated with phenolic resin. A web search using this term may result in more information.
Just a suggestion!
Reply to
Steve R.

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