Mr Ian Primus wrote:
On the CDC drives I just picked up, the entire inside
of them is covered in this foam, some of it is
starting to come off, or has stuck to cables and such
inside. A couple smaller chunks of it literally fell
off one part of the cover, the glue only holding the
particular particles of the foam to which it was
attached, and the rest of the foam falling away.
What is the best thing to do about this, especially in
something as sensitive as a disk drive? Should I
remove it? What's the best method? Is there something
I can use to replace it?
Also, for instance, inside the cover of the PDP-11/84,
there is a thin slab of foam that has turned to crud.
I plan on removing this entirely - vacuuming away what
I can and cleaning the rest off with something - what
will dissolve this? I know that trying to get the gunk
from IBM foam off your hands is nearly impossible.
Any ideas?
Thanks!
-Ian
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Billy responds:
The foam was originally for acoustic dampening. It was a dense foam without
much memory. Over time it does break down into a hideous mess. The
original life of the foam was specified at 5 years!
I've not had much luck taking in off with the modern solvents. This is one
of the times I really miss Trichloroethylene. It would really clean this
stuff up. I've used GooGone with some luck. Let it soak and it peels away.
There is usually a thin clear plastic film between the glue and the foam.
The more stubborn glues sometimes respond to acetone. Try a really diluted
type first, say fingernail polish remover, to see that it doesn't remove the
paint too.
There are several options to clean up a panel.
1. The easiest is clean up as much as you can and glue a new sheet of foam
over the mess. You should be able to buy panels of acoustic foam in
hardware stores.
2. Remove it and leave it off. But it is lots of work to get it all off.
3. Do the best clean up you can and then spray paint with a thick
rubberized paint. This seals the crumbling foam and holds it place.
No matter what you do, you are in for a messy stinky time. When the foam
breaks down, it goes everywhere. Be sure to vacuum every place you can.
Where it won't come out with a vacuum, use air pressure to blow it out -
done outside the house of course.
Good luck.
Billy