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Progress update on the two-piece
Progress update on the two-piece molds...
I built up a 5-walled box again, this time for the ventral fin, but with a slight variation from the previous box. I used MDF as the main "strongback" component for each side, but this time I separated the two halves with 3/4" strips cut from the melamine finished paper board I had left-over from the hull parting board. (I used the melamine finished board for the sidewalls to save me from having to cover it up with packing tape before use. Also, once finished these molds will be large enough that I don't expect I'll need the sidewalls in place to help keep the shape of the mold when casting parts.) I then drilled four holes into the sidewalls through which I passed the 3/32" brass rod for the pivot point in the parts, and suspended the ventral fin and rudder in the box by those rods.
Next, Clean Clay way wadded up and poked down into the box and under the parts. To work the clay into place and smooth it out I used a variety of knife handles and trimmed popsicle sticks. Once all smoothed out, many dimples were dopped into the surface with the handle of a knife and a 1/8" drill bit.
Nothing to do now but clamp down the other strongback, seal it with masking tape and pour in the rubber...
Having been allowed to kick-off over night, the mold halves were separated this morning. Here's the side of the clay that was not exposed to the rubber...
Finally, here's the mold with all the clay removed.
Tonight I'll brush down all the exposed rubber surfaces with laquer thinner thinned vaseline (to act as a parting agent), then reassemble the box and pour in "side two".
Progress update on the two-piece molds...
I built up a 5-walled box again, this time for the ventral fin, but with a slight variation from the previous box. I used MDF as the main "strongback" component for each side, but this time I separated the two halves with 3/4" strips cut from the melamine finished paper board I had left-over from the hull parting board. (I used the melamine finished board for the sidewalls to save me from having to cover it up with packing tape before use. Also, once finished these molds will be large enough that I don't expect I'll need the sidewalls in place to help keep the shape of the mold when casting parts.) I then drilled four holes into the sidewalls through which I passed the 3/32" brass rod for the pivot point in the parts, and suspended the ventral fin and rudder in the box by those rods.
Next, Clean Clay way wadded up and poked down into the box and under the parts. To work the clay into place and smooth it out I used a variety of knife handles and trimmed popsicle sticks. Once all smoothed out, many dimples were dopped into the surface with the handle of a knife and a 1/8" drill bit.
Nothing to do now but clamp down the other strongback, seal it with masking tape and pour in the rubber...
Having been allowed to kick-off over night, the mold halves were separated this morning. Here's the side of the clay that was not exposed to the rubber...
Finally, here's the mold with all the clay removed.
Tonight I'll brush down all the exposed rubber surfaces with laquer thinner thinned vaseline (to act as a parting agent), then reassemble the box and pour in "side two".
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