Date: Tue Nov 28 10:43:59 2006 Back to Contents

Author: cablem

Subject: Re: Cleaning Expo Dry-Erase Erasers

You're surprised that product engineers have engineered the eraser so
that they don't last as long, hence encouraging a higher sell rate in
order to replace them? ;-)

Our problem is mostly getting professor to recap the markers...and to
leave them in the tray so you don't have to hunt them down all over the
place when class starts.


On 11/28/2006 9:56 AM, William McNairy wrote:
> Dear All:
> Serendipity smiles on us all.
> In the dept. here at Duke dry erase erasers were thrown away, not
> cleaned, when I arrived. This meant that they were kept for a
> semester or two before being disposed of like an ancient relic. The
> downside to this was that erasers didn't erase well once the fibers
> were loaded with gunk (usually one week of use). Even worse, if
> someone used an 'oily' brand of markers, then a contaminated eraser
> would ruin a whiteboard-- requiring the use of paper towels and
> cleaner between classes.
> Since my arrival, I've cleaned the erasers on a weekly basis for our
> major lecture rooms by using a sprayer attachement in the demo room
> sink. This worked well for several years-- bit of spraying, shake off
> the water, then put on table to dry overnight.
> Expo, however, 'improved' their product by replacing the foam backing
> block with a hollow block. Unfortunately, the 'vent holes' on the
> sides of the hollow block were about 2 mm in diameter-- too small to
> allow water to flow out without vigorous and frequent shaking. In
> addition, the same engineers also put vent holes on the common side
> between the felt and the block-- thus the block would become a
> reservoir of gunk and fill with water when cleaned. On several
> occasions professors in the classroom would complain about the black
> water dripping out of not too well shaken erasers.
> Well, today during my TGiving cleaning, inspiration struck. I
> recalled the recent Tap-L thread from Urs L. describing his Swiss-Made
> Self-Flushing chalk eraser that had a perforated pipe shoved into the
> handle-- water forced into this pipe would thus flush out the chalk
> and provide a deeper cleaning. Eureka!! Down the machine shop, where
> our superb tech suggested a 'stepper drill' used for metal plates
> rather than the standard straight drill. Presto-- with some care our
> black blocks now have ~1.5 cm diameter holes on each end. The water
> jet can be force into the hole, flushing the inside of the block.
> Then a few shakes of the lamb's tail, er, block, and now one has a
> dried eraser ready for tomorrow's class. Next I'll drill out the rest
> of the W#%#!@$%%$% Expo erasers...
> Ahh, progress.
> Thanks Urs!
> bill

Machele Kindle
Lab Manager
Physics Dept.
Wake Forest University
Winston-Salem, NC 27109

Phone: 336-758-5532
Fax: 336-758-6142

"Get Fuzzy"

Bucky, the arrogant cat: Aaaaaaaa!

Rob, the geeky owner: 11:55. Right on time for his nightly freakout.

Satchet, the lovable dog: Ever notice how he runs circles in the same direction?

Buckey: Yaaaaaaaa!

Rob: Maybe the coriolis effect works on cats, too, eh?

Satchet: Ha, ha! I have NO idea what that means!

From Tue Nov 28 10:43:59 2006