[MF3D.FORUM:605] Sputnik fix up kit debuts!

[Paul Talbot <ptww@xxxxxxxxx>]

Yesterday morning I delivered the first RMM Sputnik fix
up kit to recent new subscriber/Spud purchaser Dorothy
Mladenka.  I expect the kit to evolve over time, but
this initial version adresses what I consider the most
pressing items for new Sputnik owners: reflections
off the shiny chamber walls behind each lens; light
leaks around the body/door joint area, and light leaks
coming through the door hinges.

The internal reflections are minimized by a two-stage
flocking paper baffle.  Don Lopp, Tom Deering, Brian
Reynolds, and Alan Lewis all made contributions of ideas
that I have combined and molded into the design.  Many
thanks to those folks for helping make this possible.

The two-stage flocking paper baffle works like this:

       _L_         <----- Lens
      /   \        <----- First baffle (cone shape)
     /_   _\       <----- Square opening in second baffle
     |     |       <----- "Arms" of second baffle
    ---------      <----- Film

The first baffle is a cone cut from flocking paper.  The
small opening toward the lens is roughly the size of the
lens retaining ring.  The large opening at the back (film)
side has a diameter about the width of the chamber.  The
cone is held in place simply by taping it to the chamber
walls.  Brian Reynolds' mention of a formula for model
rocketry "stage transitions" (as an idea for lens shades)
made the development of this part of the kit possible.

The second baffle is a modified version of one that Don
Lopp designed.  Shape and size are virtually the same,
but flocking paper has been added to the surfaces that
face the film.  Although the second baffle can just be
placed in position and used that way, cementing it to
the chamber walls is advised.  (Otherwise it has a
tendency to cut off a small amount of the image area
on the film.)

Although the cone baffle is made only from flocking paper,
the rectangular baffle is made of flocking paper cemented
to a plain paper backing.  The flocking paper by itself
does not hold the shape of the second baffle well enough
to be used without the paper backing.

Paper templates and pieces of flocking paper required to
cut and form the baffles are one major part of the kit.

I have settled on the imported light trap foam from
Micro-Tools (Fargo Enterprises) for use in the V-grooves
of the door/body joint area.  The light trap foam material
avoids the problem of the doors becoming difficult to close
when black yarn is used in the V=grooves.  Several pre-cut
thin strips of light trap foam are also in the kit.

Finally, for the serious light leaks in the hinge area, the
kit includes some solid black shutter curtain material, also
from Micro-Tools.  Cementing the SCM to the front wall of each
film well, right where the film retaining tabs are attached,
very effectively blocks the light that comes through the hinges.

For this group, which I know has a lot of do-it-yourselfers,
I am offering the kit as a collection of the required materials,
templates for cutting them, and detailed instructions, for $15,
plus $1.50 postage ($3.50 for priority mail).  For the general
Sputnik-using public (e.g., at NSA), I'll likely offer ready-made
baffles at a higher price.  The kit contents list and
instructions
can be read now at:
http://www.rmm3d.com/shooting/fix_kit_instr.html

If it were *me* trying to digest those instructions, I'm sure it
would take a week to figure them out and a month to work up the
determination to tackle the job.  But Dorothy's friend David was
able to scan over them and know pretty much exactly what to do
with
all the pieces in about 5 minutes flat.  So I think a lot of the
folks on this list will have no trouble at all with this stuff.

Please contact me off-list if you would prefer to receive the
baffles ready-to-use instead of as a "project aid" like this.

Note that sun shades are not yet in the kit.  I'm going to take
a look at the options for sun shades next.

Paul Talbot