tmacklin
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- Feb 1, 2012
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It's been too cold and nasty to do much woodwork in my workshop so I've been repairing old rockets. As I do mostly scratch builds, often from non-rocketry parts, I find myself looking for ways to make what I need. Today, I was looking for a way to house a 29 mm motor mount into a 1 1/2" (38 mm) i.d. mailing tube. Cutting conventional centering rings from plywood using hand tools would be an exercise in futility, so I borrowed from my pyro background and settled on making a convolute wound paper tube which will ultimately be cut into short slivers forming centering rings.
I started with a section of standard LOC 29 mm motor mount tubing about 14 inches long. To this I made a smooth wrap of Reynolds wax paper about 1.5 times the circumference and secured it with several short pieces of Scotch Magic Mending tape, making a bond breaker for any glue that might squeeze out. Next I cut pieces of red rosin paper into sections 8 inches wide by 18 inches long and began gluing and wrapping these around my "mandrel". The glue is nothing more than good old Elmer's White glue spread with one of those small, flat spreaders that comes with the Bondo Auto Body filler kits. The trick is to spread the glue in a thin film and roll the paper upon itself in quick motion before the water in the glue has time to swell and wrinkle the paper. It's an acquired skill, trust me!
In order to make up the difference in diameters between the outside of the motor mount (1.22 in.) and the inside of the body tube (1.50 in.) required a wall thickness of 0.14 inches (or 9/64 of an inch). I ended up wrapping 4 - 18 inch pieces of red rosin paper, 6 feet, to accomplish this task. Very therapeutic I might add. :grin:
I can post some pictures if any one is interested?
I started with a section of standard LOC 29 mm motor mount tubing about 14 inches long. To this I made a smooth wrap of Reynolds wax paper about 1.5 times the circumference and secured it with several short pieces of Scotch Magic Mending tape, making a bond breaker for any glue that might squeeze out. Next I cut pieces of red rosin paper into sections 8 inches wide by 18 inches long and began gluing and wrapping these around my "mandrel". The glue is nothing more than good old Elmer's White glue spread with one of those small, flat spreaders that comes with the Bondo Auto Body filler kits. The trick is to spread the glue in a thin film and roll the paper upon itself in quick motion before the water in the glue has time to swell and wrinkle the paper. It's an acquired skill, trust me!
In order to make up the difference in diameters between the outside of the motor mount (1.22 in.) and the inside of the body tube (1.50 in.) required a wall thickness of 0.14 inches (or 9/64 of an inch). I ended up wrapping 4 - 18 inch pieces of red rosin paper, 6 feet, to accomplish this task. Very therapeutic I might add. :grin:
I can post some pictures if any one is interested?
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