Hi,
Sorry to disappoint but my Kern & Sohn GmbH CM320-1 scales (Either came from
RS or Maplin, I can't remember!) pass the test. The sum of the parts even
equal the whole (A4 80g/m2 cut into 32)
Simon
504 G-BZTN
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Ronald J.
Parigoris
Subject: Europa-List: Caution for those using Electronic Scales ? Mix info
--> <rparigor@suffolk.lib.ny.us>
Just a word of caution for those of you using Electronic Scales.
So far I have not seen a electronic scale under many hundreds of dollars
that maintains accuracy if you add to cup when cup is on scale!!!!!!
What happens is the scale has some sort of threshold level. If it is not
reached then the scale resets.
What this means if you are trying to target something exact, and are adding
small amounts, the scale may be resetting and giving you false
measurements!!!!!!!
Simple test
Zero out scale.
Put on a piece of 8.5x11 paper and note weight
Now cut up paper into pieces 2 times the size of a postage stamp.
Now zero out scale, and place 1 piece of paper on the scale at a time,
waiting a few seconds between adding. You will get quite the shock after you
added a few full sized pieces of paper and the scale reads zero!!!!!
I take off cup between adding, this way when you place it back, since you
are way beyond threshold accuracy remains intact.
I also do a little test to catch if i forgot to tare the scale or it reset.
I first zero scale. then weigh the empty cup and note its weight. then i
tare the scale with cup. Then add resin and hardener. Now I rezero scale and
weigh the cup/resin and hardener. On your mini worksheet you added the
cup/resin and hardener. If it is not the same on paper as what you are
reading on scale, then either you forgot to tare the cup, or the scale
reset, in other words trash that mix.
I called Aeropoxy. For structural mixes, keep proportions within 5%. For non
structural mixes keep within 10%. Please note that it will harden if off by
more than 25%!!!! The problem is the glass transition temperature really
falls off. Another tip was if you need to be off, make it resin rich not
hardener rich.
Just figured I would mention.
Just for general knowledge, please post type of scale that can pass the copy
paper test.
Ron Parigoris
Another note: probably an excellent idea to not keep redux measurement sheet
anywhere near the Resin mix sheet. I keep mine with redux, and have it
outlined in green. If you have it on the other side of the Epoxy sheet, and
you are having a bad day..... Lets see 40 to 100, compared to aeropoxy 27 to
100,,OK 27 - 40 / 27 = 48% So that mix is 48% off target. far cry from the
5% max. structural target if you used redux scale for Aeropoxy. But then
again you were probably adding hardener on the scale, which brought the mix
just perfect ;-)
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