Re: Train of Thought- Sanding resin flash, or: avoiding bloody finger...


Charles Hladik
 

Denny,
I like the entire process but for the sandpaper. I use a sanding
screen. These don't load up like sandpaper and are used for sanding sheetrock
mud (backdrops?) and hardwood flooring. Usually available at your favorite
home improvement store.
Chuck Hladik
Rutland Railroad
Virginia Division

In a message dated 8/20/2010 12:08:33 A.M. Eastern Daylight Time,
danspach@... writes:




Friends, I am once again engaging in my usual summer push-on-the-porch to
build at least several fine kits, some really challenging, and others merely
enjoyable. I have no grand plan or scheme, but simply choose those
projects that catch my fancy and interest.

One of my current projects is a thoroughly delightful Westerfield
Milwaukee Road 36' drop-door stock car kit, and as one might expect, the exquisite
flat sides with their myriads of slats and fine bracing are all laid out in
high relief on a relatively thick tough slab of resin. Now, the entire
project depends upon cleaning out all flash between these fine slats and
braces without collateral damage, the produced spaces to be squarely and
smoothly cleared. In this regard, all know what to do: sand the backs of these
sides until the flash between the slats becomes so thin that it can be easily
cleaned out with the hosts of various sharp instruments that are right at
hand (none of which really fit, or do the job!).

So the sanding of these large pieces begin: a segment of 220 grit
wet-or-dry sandpaper is laid out flat; the side is placed on its back; and with
fingers spread-eagled the length and width of the slide, the side is moved
back and forth with sufficient pressure to engage the cutting sand paper
granules, but not enough to grab the sandpaper and bunch it up with the creases
that will only cause future problems.

Well, after a considerable length of time (I count to 100 slowly, with
about three swipes per count per bout of sanding), I take a look and- I find
that the flash is indeed minutely being removed, but primarily only under
the tips of my "light" fingers. I change the position of my fingers, but I do
not get very far because the sand paper is now loading up. I wash the
sandpaper with a drop of detergent, dry it on a tea towel, and then get back to
sanding. I rotate the side; I try to flatten my finger tips; I change my
finger positions; I load up again; I wash again, and so on. Finally, I
detect that the the bloom is off the rose on this once-fresh sandpaper (resin
must be harder than I would imagine), and new sand paper is called for.

Now, I steal the small broiler pan out of the toaster over, fill it with
detergent water, submerge the sandpaper, and commence sanding again, this
time underwater. Things move faster (the paper is now self cleaning), and at
least an elapsed 1/2 hour each after starting, finally the sides are
becoming thin enough so that the flash between the slats and braces is thin
enough to attack with my sharp sticks. However, at the same time, the sides are
also becoming thin enough to become somewhat delicate to the handling that
is still necessary.

But wait! The much thinned flash must still be removed so that the slats
and braces have clean sharp edges, both in fact and in perception. This is
undertaken with my principal sharp stick: a #11 Xacto blade whose point has
been specially honed on an Arkansas stone, and whose "square" backside has
also been flat-sharpened- i.e. the 90ยบ corners are also made as sharp as
possible so that with only only the slightest tip, the backside will cut
-actually scrape- just about as well as the knife edge on the other side. With
this wonder tool, and a variety of stiff brushes, pokers, etc. and about an
expended time of @hour, at last the exquisite, now fully-fenestrated sides
are ready for their ends to be mitered to fit the car ends (also mitered).

I write this all up so that I can learn from others how THEY handle this
relatively common but time consuming and tedious situation. My finger prints
have probably been erased from my fingers during previous bouts of such
resin flash sanding with much smaller pieces, the skin of the fingers being
freshly sanded -bloody even- along with the target resin part.

I will say that demanding kits like this make me realize once again what a
fulfilling delightful hobby this is!

Denny

H-mmm.
Denny S. Anspach, MD
Okoboji, Iowa

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