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Improved rounded edge mold

Using the drill press in the machine shop i drilled larger holes that

  1. Were wider then the bolts which go through them which will allow the boards to be tightened together with the nut and will prevent the threads from holding them apart slightly.
  2. Were drilled perpendicular so the bolts go in straight.   (this way the mold is level)


Wood Mold

After the we tried the latex mold we decieded to go back to using the wood mold idea again.

But this time we decieded we'd give the mold a better shape.  So using adobe photoshop i created a rounded rectangle with the best compromise between edge radius and it's effect on the overall size of the device.  Then converted it to an HPGL file which could be used by the machine.

One problem arised when i went to mill the board.  The dpi i had used in adobe didn't translate properly to the dpi in the milling program.  So measuring the size of each i determined that a scaling factor would be needed of approximately .6  == ( size of printed drawing from adobe / size of milled drawing )

By experimenting with the scale factor and making a few cuts in a piece of plywood i determined the ideal scale factors.

Notes on Scale Factors:
    .566 = scale factor to use when you are trying to make a mold cutout
    .584 = scale factor to use if you want the piece which get's cutout to be the actual size of the mold.  (useful for making say a rubber mold)


Latex Molds

At a crafts store I picked up some Latex Mold Builder.  Coats of the latex are brushed onto the object you want to mold until you've applied about 10 coats or it's thick enough.  The latex molds created pretty good molds of the piece of plexiglass we molded around but the casting that resulted from the mold was pretty tacky.

We could of used this type of mold but the process of making a mold out of the latex was kind of a turn off.



Wax Molds

One of the first molds we tried to make was out of wax.  The wax Molds didn't work out because we couldn't get the the mold's smooth enough and they were succeptible to warping out of shape.


Left: Melting Wax on the stove
Right: Making a mold using a piece of plexiglass the same size as the keychain.  Duct tape was put on the mold to help remove the plexiglass from the mold once it hardened

The results:

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