Re: weave showing

Posted by Laszlo on Apr 22, 2004

You can get rid of all your pits with the following:

1. Measure the radius of curvature of your hull at the pitty point. That is, extend the arc of the hull until it closes back onto itself, and take half the diameter of the circle that it forms. Fortunately, plywood only bends in one direction, so you don't have to worry about which radius to use.

2. Lay out a clear area that's twice as long as the radius. Put the boat at one end and set up a small table at the other.

3. On the small table, set up an LED powered by a 9-volt battery (don't forget the limiting resistor). Put a piece of 2"x2" aluminum foil against the LED between the LED and the boat. Punch the smallest, roundest pinhole you can in the aluminum foil before doing this and make sure that the hole is aimed at the boat.

4. Put your eye next to the aluminum foil, looking at the boat. The boat should be evenly illuminated by the LED. If not, move the LED left. If the illumination moves left, move the LED back until the illumination is even. If the illumination moves right, move the LED forward until the illumination is even. At the perfect point, moving the LED left or right will result in an instantaneous change of illumination over the entire hull.

5. Now comes the fun part. At the point where you had your eye, vertically mount a razor blade so that it acts as a continuation of the foil barrier. If you move the blade left/right, the hull will instantly dim and brighten. This is perfection. What you will actually see, though, is a bright hull covered with pits that range in size down to 0.000002 inch.

Now you can start filling those pits with epoxy or varnish. Keep repeating the test until the boat appears completely smooth. At that point you can rest assured that all pits down to 1/8 of a wavelength of yellow light have been filled and you have built a fine optical instrument.

Or you can just say no and go paddling instead.

:-)

Laszlo

In Response to: Re: weave showing by Doug Judd on Apr 22, 2004

Replies:

• Revealing Post by Kurt Maurer on Apr 22, 2004
  • Re: Revealing Post by Laszlo on Apr 22, 2004
    • Re: Revealing Post by Mark Camp on Apr 23, 2004
• .000002" by LeeG on Apr 22, 2004
• Re: weave showing by Chip Veres on Apr 22, 2004
  • Re: weave showing by Mark Camp on Apr 23, 2004
    • Re: weave showing by Laszlo on Apr 23, 2004
      • tests by LeeG on Apr 23, 2004
        • Re: tests by Terry Mcadams on Apr 23, 2004
          • Re: tests by LeeG on Apr 23, 2004