Brian,
   Your work looks excellent. Within the next year I am going to
   have to build a complete cowl from scratch and as yet know nothing
   about glass work, mold making, weave to use, layers to use, etc. So
   any small tidbits of info on what you did would help. I save
   everything pertaining to glass layups but, so far, most want to show
   off their excellent work but not reveal how they did it. Also, I
   would like to know the general dimensions and weight of the completed
   cowl if possible.
   Thank you,
   Randy


Thank you. I'm art work until monday, so I'll get you the weight of the
cowl at that time. The cowl is 44 inches from firewall to spinner. I
wrapped the engine in a couple of rolls of saran wrap, then rolled some
screen material over that to hold the two part foam that I slathered
over the engine. Here's a tip- bulk out the whole thing by putting
newspapers or hunks of styrofoam around the engine to get it near the
size of what you want the plug to be.(The foam isn't too cheap, and
there's no advantage to useing lots of it.) Then wrap the whole thing in
saran wrap & screen.  after you get the foam slathered on and it expands
and hardens(you'll have to do it in small batches and keep filling until
you get enough size) then you can sculpt it down to close to where you
want it.

I used a surfoam tool and 50 grit sandpaper glued to a piece
of  1/4" plywood. I then got a bucket of drywall compound and coated the
whole thing and then sanded it down to a very smooth finish. You'll have
to sand and add drywall compound a few times. You want a nice smooth
contour. I checked the contour from side to side with a template cut
from cardboard. I then painted two or three coats of ordinary latex
paint onto the the plug and then waxed it.  I had a problem with the
resin making some of the foam underneath shrink a bit, so I had to fill
in with some more dry wall compound. In retrospect, I think that I
shouild have had a much thicker coat of drywall compound, it remains
stable when in contact with the polyester resin., and It's way cheaper
than the expanding foam. If you have layer of drywall compound that was
1/2 inch thick, I think that you would avoid any stability problems.

When you have the plug the way you want it, wax it and  lay up from 4-5
layers of plain weave 5.8 oz cloth.  Your probably better off  laying no
more than two layers at a time. I had no problem laying whole sheets
over the top part of the cowl, but found it much easier to use smaller
pieces around 1 foot square. After you have all your layups done, you
can fill low spots with resin mixed with microballons, sand and repeat
until you have the finish that you can paint. I used a 2 x4  kerfed so
it would bend and clamped it on the side of the cowl to use as a guide
to cut the cowl off. It made nice straight cuts  using a die grinder
with a 3" wheel. Lots of gentle, loving prying was required to remove
the cowl from the plug, with a lot of the plug remaining stuck to the
cowl. I borrowed my neighbor's pressure  washer and cleaned that crap off.

One tip- I have a flange riveted to my firewall that the cowl fastens to
with piano hinges. Before you cut off your cowl. drill a couple of
holes though the cowl into whatever you are mounting it to so you have
reference points, and can cleco the cowl to the airplane. Also, drill
and cleco a few pieces of aluminum sheet between the top and bottom
halves of the cowl to use as a reference.

The forward bulkhead was cut out of 1/2"  hexcell and bonded in.

I'm sure that this whole procedure raises a lot of questions, feel free
to contact me if you think I can be of assistance.
bktrub@aol.com <mailto:bktrub@aol.com>



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