On Mon, 10 Aug 2009 09:15:44 -0700, Jeff Liebermann wrote:

On Mon, 10 Aug 2009 08:23:43 +0100, "N_Cook" wrote:

Thanks for some interesting ideas. I was thinking of using some expanded
aluminium, anchored into the aluminium, with a fresh drilled small hole
or two and small nut/bolts. To give a scaffold for epoxy to anchor onto.
Also underscore the plastic to give a bit of key. What is the function
of aluminium dust in epoxy, other than a colourant?

Epoxy is hard and brittle. Aluminum is soft an malleable. If you try
to drill and tap straight epoxy, it will usually crack. The aluminum
provides a cushion. You can buy aluminum filled epoxy at the hardware
store, but I've found that it doesn't have enough aluminum and is mostly
brittle epoxy. So, I mixed my own. The hard part was finding the
aluminum powder. I made some by destroying a grinding wheel and
grinding down a slab of dead soft (pure) aluminum. There are various
instructions on the net for making aluminum powder. One uses aluminum
foil run through a shredder, and then through a ball mill for 2 weeks.
No thanks. Anyway, use only as much epoxy as necessary to hold the dust
together. If sufficiently large volume, insert reinforcing bars, such
as a paper clip, into the mix for strength.

Something I haven't tried is to insert the matching (3mm?) screw into
the partial hole, cover it with grease or some kind of mold release, and
then build up the epoxy/aluminum/whatever material around it. When it
hardens, just remove the screw and you have an instant threaded hole.
The problem is that it has a weak spot guaranteed to cause a stress
crack at the screw hole.

To the others in the thread , if I wanted to get hints on (apparently ,
oftn walletctomy) buying specific replacement stuff from e-bay or how to
google I wouldn't be posting repair queries to sci.electronics.repair
which has the word repair in the title. Why do you think I deliberately
did not mention make and model?

If you actually want to repair some item, the idea is to supply as much
information about the item and its condition as possible. Minimalist
postings are useful academic exercises, but often wander badly in a
futile attempt to guess your circumstances. More specifically:
1. What problem are you trying to solve? 2. What do you have to work
with? (Make, model, version, etc). 3. What have you done so far and
what happened? There's plenty more info that would be useful, but the
aforementioned are the essentials. Anything less usually results in
guesswork and topic drift. I won't speculate as to your motivations for
intentionally withholding useful information.

Try this:

http://www.freemansupply.com/Freeman801Aluminum.htm

or a similar product.

It's worked for me.

Al