received many requests for the scanned plans file for the Comet Spark
free flight model. Along with the plans, I provide three files that contain the printwood patterns. Printwood patterns,
for those of you unfamiliar with the term, are the ink pattern that were printed directly onto the balsa so that the
model builder could cut the pieces out. This was the el cheapo way of producing a kit where the expense of die cutting
was not incurred by the manufacturer. Truth be told, the die cutting was usually so lousy that you were better off
cutting the parts yourself. Well, it would be if companies like Comet didn't make a habit of using balsa with about
the same density and hardness as oak. Cutting 1/16" square longerons in fuselage bulkheads or wing spar notches in
wing ribs was a real challenge - especially if you were a kid whose only form of razor sharp tool was a used blade
from your father's razor.
By the way, the printwood patterns are necessary because most plans from kits do not include templates for all
of the sheet balsa parts. That is as true today as it was 50 years ago.
When using my computer image files for making parts templates, it is necessary to devise a means for transferring
the full-size patterns to the balsa. Fortunately, Mr. Robin Tole has created a method that uses Avery label sheets
and a standard ink jet (or laser) printer. He was kind enough to provide the details, along with photos, so I'll let
him do the talking.
Printwood Patterns on Avery Label Sheet
(top: fresh from the printer, bottom: stuck to
******** July 12, 2009 ********
I have taken some pictures of the sequence of events for cutting parts from templates printed onto Address Labels.
When I had the idea to use this technique, the largest labels I could buy locally were two A5 labels on a single
I stick Scotch ‘Magic Tape’ over the middle join to avoid the labels separating when peeling them off the backing
The pictures show a wing part for ‘Sparky’ being prepared.
There is probably a way to print the images full size to the rule scales without resorting to scaling with the
I don’t know how to do this though.
I re-sized the JPG images as a batch - the originals were too large to e-mail. I found a piece of free software
to do this (Easy Thumbnails).
I hope that the pictures are acceptable.
******** END ********
Avery Label Sheet Stuck to Balsa
Note that label printout has wood grain look to it since it was scanned from actual
Wing Tip Piece Cut Out (left: pattern label still on. right: bare balsa)