and another thing....

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Well-Known Member
Sep 20, 2003
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How does one mask a conic section? How do I paint the tip of the nose cone black with a nice clean line perpendicular to the long axis of the nose cone?

tips welcome

I have a collection of scrap centering rings that I cut when I was practicing with my RotoZip that are 7.5" diameter. I cut out different size holes in these (from about 0.5" up to 38mm-54mm) and place one over the tip of the nose cone. Make sure it is level all around, and spray above the ring. Gives nice, clean lines!
I cut a tangent transition out of the sticky part of a Post-It note and use it for a mask. The top diameter equal to the diameter of the nose cone at the paint transition and bottom diameter and length longer and wider than the rest of the cone. To keep the paint from seeping through you can make 1/8 inch mask past the end of the transition with Parafilm M or a good masking tape. I did that on my clone of the Centuri Jayhawk in this tread:

Bruce S. Levison, NAR #69055
You can also go the mathematical route and measure the circumference of the cone at the edge of your masking, work backwards to find the radius, use a compass to draw a circle of that radius in the middle of a piece of card stock, and cut out the circle. Place that card stock circle over your nose until it's snug and paint as usual (lots of light coats). It's worked well for me!