Thread: B-29 Plans
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Old Jul 25, 2003, 09:39 AM
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Brighton, MI USA
Joined Jun 2000
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Chris,

To cut the round fuse pieces, I used my home built hot wire with the following procedure:

1.) Glued up a square blank of foam (see page 2 of this thread) and attached a circular template to each end.
2.) Place the blank over the corner of a table so the ends of the cutting bow hang over the edge.
3.) Start cutting at the top center of the blank, when the wire gets to the templates push it off to one side and let gravity start to work.
4.) When the wire gets near to 90 degrees, move the wire away from the templates and cut the power to the hot wire
5.) Rotate the blank 90 degrees, and start cutting again.

I advise against holding the blank in the air and trying to cut it in one pass. The foam is not that stiff and may bend. Then you'll end up with a banana! Keeping it flat on a table will help keep the fuse straight.

You may end up with a few bumps in the finished tube, but the major work will be done and a few seconds with a sanding block will true it up.

To hollow out the inside:

1.) Push a piece of music wire through the center of the tube. Use this to thread the cutting wire through the foam.
2.) Attach the templates and connect up the cutting wire.
3.) Use gravity to pull the cutting wire through the foam. When the wire hits the templates rotate the tube as necessary. This part you can do in one shot holding it in the air. The inside shape is not that critical.

One thing I've learned in cutting foam is to let gravity do the work if possible. Gravity is much steadier than your hand and will pull both sides of the bow evenly.

I hope this helps.

-Jim
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Last edited by Jim Young; Jul 25, 2003 at 09:49 AM.
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