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[ATM] Stubborn TDE
> First, please tell us how hard your pitch is. The easiest way to
> describe it is to tell us how long it takes your pitch channels to
> close (or require serious trimming) during normal polishing. 6 hrs is
> too long. 30 minutes ot too short. 2-4 hrs is best, in my experience.
With the warmer summer temperatures, it takes about 2-3 hours for the channels to close. I am
amazed how much the softness can change with temperature, though. In the spring (when I was
doing hour-long polishing sessions), I polished for more than 10 hours before I needed to trim
the channels.
> Second, please describe your polishing stroke. I like to use moderate
> polishing pressure, which is still probably 15 lbs of downward
> pressure. This depends on how the pitch is behaving, however.
I would say I am using moderate pressure, something like 10 lbs. The stroke is COC or a narrow W
(either one seemed to have the same effect) with a stroke length of 1 inch.
> Last, please tell us what the mirror is made of (plate? Pyrex?) and
> what the tool substrate is (what the pitch is poured on).
The mirror is Pyrex, 1 inch thick. The tool substrate is dental stone, also 1 inch thick. The
tool is full-size (6" diameter).
One thing I'm thinking now is maybe my 1 inch stroke is too short - so short it isn't doing
much. I might try increasing the stroke length to 1.5" (1/4 diameter).
Jerry suggested I try doing accented pressure closer to the edge, since the TDE is narrow.
But I think I got about as close to the edge as I can - about 1 mm. I applied pressure with
my thumb at the very edge of the tool. I tried various narrow and wide W strokes with
this type of accented pressure, to no avail. I wonder, should I try a straight forward
and backward stroke (rather than a W) when I apply accented pressure, with this narrow
of a TDE?
Thanks for all your feedback.
David
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