Grant Erwin wrote:
Yesterday I ran across a picture in a book of a pipe which had been
welded into a semi-spherical closed end. If you think of the top half of
a tennis ball cut in half with a chop saw, then rotated 90° and again
cut in half (so that the top half of the tennis ball was cut in
quarters) and then the quarters were lifted straight up, if you just
looked at that upper profile of the tennis ball and then if you layed
out a proportional pattern on the end of a piece of pipe and cut away
the material in between the "petals", then the tabs could be forged over
into a semispherical shape and welded up to form the shape I saw yesterday.

I thought it looked cool. Naturally, being the curious type, I started
thinking about how to lay it out on a pipe from first principles. Hoo,
boy, that one is a tricky layout problem. Anyone know how to approach it?

GWE

That's called an orange peel. The layout is described in detail in "The
Pipe Fitter's and Pipe Welder's Handbook" by Thomas A. Frankland, also
called the Frankland book by many pipe fitters. Looks like data is
provided for 4 to 8 "arms" depending on the size of the pipe.

Gary Brady
Austin, TX