Model Forum / Radio Controlled / Air Models / April 2004

Oh, I get it now.  You're physically handicapped!  I'm so sorry.  Maybe you
need a Health Care Aide to help you up when you fall.
Dr.1 Driver
"There's a Hun in the sun!"

Must be all that hitting your head when you fall off your chair that makes
you so dumb, I guess.

CA cures through a chemical reaction.  It has no water or solvents in it so
it can't "dry".

--
Paul McIntosh
http://www.rc-bearings.com

You need to protect your head when you fall off the chair.

Since I spend a good part of my time at work in a chemical laboratory, I
decided yesterday afternoon to "dry" some samples of various CA adhesives
and measure weight loss. I carefully weighed a few samples of thin and
medium CA on an analytical balance accurate to 1/10 milligram. These samples
were held in laboratory weighing dishes. To kick them off (as the surface
chemistry of a sterile weigh dish will not catalyze CA for ages or ever), I
treated several strips of paper with raw CA catalyst (no solvent, CA kicker
is usually about 2% catalyst and 98% solvent) which I lay across the top of
the weigh tin so that the catalyst (which is somewhat volatile) would do
it's trick overnight.

This morning I checked the samples, and they were all fully cured, hard as
nails. So I weighed them.

Gosh, surprise surprise! The weight loss varies between zero and one half a
percent. As these are small samples some of that 1/2% can likely be
attributed to weighing error. Some might be volatiles in the adhesive
wandering off. At that level who cares.

NO significant weight loss. In fact numbers like that equate to NO weight
loss.

So.. rather than continue to argue perhaps you should simply realize that
you have your facts wrong. This information could actually be useful to you.

And btw, I do know the difference between wet and dry. Do you now understand
the difference between drying and curing? Dr.1 does, Paul does, I do.

Mike D.

Isn't it the water in the air that causes CA to cure ?  If so the addition of
water molecules to the mix may actually result in
cured CA weighing more that liquid CA.

 Strathboy,

   This your second post to me, telling me to locate my servos to
achieve the correct balance point.  The first was in regard to the Kadet
Senior ARF, now this one.  In both cases you've shown your ignorance of
the models in question.  Both of them come out of the box with the servo
trays permanently installed and with pushrod materials supplied to reach
those trays.  Seems logical to try these servo locations before electing
to modify the model.  In the case of the Extreme Stick, the servo tray
is located about as far back as it can be, under the wing, even so, the
stock model is noseheavy with any engine.

  As for drilling the engine mount; in the case of the KSA, the engine
is located on the mount so as to place the prop drive washer just clear
of the cowl and still allow cowl removal for maintenance.  In the ESA, I
used a light DB mount with the engine as far back on it as it would go
and still allow the fuel lines to clear it.  The ESA required major
surgery to balance it without ballast.

  Your sarcastic remark about ARF building comes as a surprise to me,
coming from someone who thought that preselecting wing wood in order to
have the finished wing panels come out equal in weight was unusually
meticulous.  Aren't you the guy who suggested that adding weight to the
finished wing was a lot easier?

  You really ought to educate yourself a bit more before about the
subject(s) before you expose your backside for all to see.

  CR

And these are aircraft your concerned with tracking in both inside and
outside loops, right?

Pitch is where its at!!!