Hello MMD.  I hadn't realized that collecting piano rolls might be
dangerous, until about ten minutes ago.  I have been going through my
classical 88-note rolls looking for boxes whose end labels have become
damaged, ripped off, or otherwise illegible.  I've pulled these rolls
off the shelf, repaired the boxes where necessary, and printed new
labels.

When there is a damaged label on a box, I like to soak it off before
pasting on a new one.  During the past week or so I have tried putting
the box in our microwave oven for a ten second burst, or two or three,
after painting water onto the label.  This does seem to speed up the
glue softening process.

This morning I put a Metro-Art box with a half chewed-off label into
the microwave and pressed the ten-second button.  After about six
seconds there was a "phloomp" sound and a flash of orange-yellow light,
and the view of the inside of the oven was obscured by roiling smoke.

I opened the door in a hurry and pulled out the box, which, to my
relief, wasn't actually burning.  However, the back end of the box,
over which I had glued a square of black paper yesterday, now had
something resembling a black sunflower, with a circular black patch
in the middle, surrounded by little outwards-curling petals.

Obviously a bubble had formed under my new paper, and burst outwards.
But the bubble can't have consisted just of steam; there must have been
a flammable gas in there too.  I had used ordinary PVA glue and would
have thought it to be well and truly dry after 24 hours.

I am now labouring under a wife-imposed embargo on microwave piano
roll activities.

John Phillips in Hobart, Tasmania

 [ Food becomes hot because it absorbs microwave energy.  Paper
 [ coated with carbon black (e.g., laser printer toner) absorbs
 [ microwave energy very efficiently, so it heats quickly!  -- Robbie