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Whew...somebody is writing lots of fancy
procedures! In my experience all of them are pointless beyond just
three things:
1) Surface oxidation should be removed. Aluminum
etchants do nicely, sandpaper does well too as does scrubbing with scouring
powders. Bon-Ami is great.
2) Grease is the enemy of a good bond. You can
vapor degrease with tri-chlor or stick the part in a cathode vacuum etcher or
bombard the surface with anti-protons---but a little elbow grease and a clean
solvent does 99.99% as well. If it is safe to do, flaming the surface with
a propane torch just moments before bonding would be a fine touch to drive off
any surface condensation.
3) The biggest error in bonding is inadequate
bond-line thickness. Epoxy does not penetrate well. If you squeeze out
all the epoxy in the bond interface you might as
well be using spittle for all the good it will do. Remember that wherever the
parts touch each other--there is no adhesive! Be careful with
clamping!
Heat helps epoxy bonding tremendously. Bake it
if you can.
Recently I used some 25-year-old epoxy putty
sticks for a non-critical application. Ten seconds in the microwave and they
worked like new. I am inclined to ignore expiration dates. For critical
applications you will have to decide, but then I am not comfortable
with adhesive bonds used in life-critical applications at
all.
Regards,
"The man who carries a cat by the
tail
learns something that can be learned
in no other
way."
--Mark Twain
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