From: David Ross (ross_at_math.hawaii.edu)
Date: Sat Aug 05 2000 - 04:00:50 EDT
"epoxy resin and a little glass cloth is better and more permanent.."
All-purpose solutions are rarely better than ones custom-designed for
the problem.
Resin adhesives are problematic on some ABS composition plastics, as
they can have difficulty
keying to the surface. Some epoxies will work somewhat on some laptop
cases, depending on the
epoxy and the particular model's case material.
Solvent adhesives have been created for precisely this problem. The
advantage of solvent adhesives is that they partly melt the plastic (to
an imperceptible depth) and create a nice keyed surface; one can get a
remarkably strong bond even if there are few contact points. However
they are not as good as epoxy for filling big gaps, and might offer
less structural integrity than one would get with a fiberglass
reinforcement. They are also inferior in a mixed-material setting.
Depending on the nature of the break, a combination of these techniques
might be best (for example,
solvent adhesive for the plastic-plastic contact points, with an epoxy
gap fill, and glass cloth for reinforcement). However, if something
like epoxy is used for the plastic-plastic contact then
in fact the join will be plastic-epoxy-plastic, and susceptible to flex
failure.
Unfortunately, if Goop has already been used on the break, then it might
not be safely reglueable
with non-silicone adhesives. No matter how well you clean the old glue
off/out of the break,
it has contaminated the surface and other adhesives might not correctly
adhere. (Epoxy is somewhat better in this regard, as the inferior
epoxy/plastic adhesion makes it easier to remove than Goop.)
On the plus side, Goop is a great mixed-material adhesive, so should do
a better job than most on holding your chopsticks to your case:-)
BTW, if it sounds like I'm obsessed with adhesives - it's true, an
obsession which provides a great source of amusement for my wife. When
I was younger I thought that it sufficed to keep white glue,
epoxy, and CA glues on my shelf; now these are the adhesives I use
least.
- David R.
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