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A plaster cast for
© Frank Ford, 8/16/00; Photos by FF, 8/15/00
Every so often I want to generate a precise template of a neck contour, or other instrument surface. Today, my job was to measure and record the dimensions of a neck so it could be replicated.
The owner of this Benedetto jazz guitar is in the process of ordering a new Maccaferri style guitar from Maurice Dupont in Cognac, France. He asked me to measure the dimensions of the neck at various points, and to draw an exact template of the contour so Maurice could copy it as precisely as possible. I chose the third fret position as the best place to copy the contour.
First, I wrapped a turn of thin plastic film around the area in question:
As plaster of Paris cures, it generates a bit of heat and moisture, so I wanted a bit of extra protection for the finish.
I mixed up a batch of plaster to about the consistency of Heinz ketchup:
And dumped it into a zip lock plastic bag:
Mashing the bag down around the neck, I tried to keep it as smooth as possible in the area of contact:
A while later I was able to slide the bag off and trim the excess off:
A quick trip through the bandsaw at the third fret position gave me a nice flat cut so I could handle the cast easily:
See? I marked the bass and treble sides so I wouldn't get my tracing reversed:
With a really fine point on my little mechanical pencil, I was able to trace right at the edge:
In fact, the tiny line just about matches the thickness of the plastic film layers.
Here's my little smiley face:
Now, the hard part - making the new neck to match.
That's up to Maurice. . .
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