Sender: <marv@lancaironline.net> (Marvin Kaye)
To: lml
Date: Mon, 14 Oct 2002 08:10:59 -0400
Message-ID: <redirect-1805026@logan.com>
From: Newlan2dl@aol.com
Subject: Re: [LML] White Foam
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Hi Jerry

Any of the strofoams work-either beaded or solid-and you can get it at a 
hardware store as insulation.  The blue foam shapes easily and is cheap.  
However my preference for plug making is wood.  The problem with the "lost 
wax" method of laminating is that you end up with a God awful bunch of toxic 
sludge and the back of the part that was against the part is left very rough 
and requires a lot of cleaning to get rid of the residue.  A slight variation 
I did use once was to tape over the plug and once, I also stretched some 
Saran wrap over it.  That also allowed me to use polyester resin for the 
part.  

If you want to go fancy, build in wood and finish the surface with Ram primer 
or Featherfill, both are polyester based spray or brush on sanding primers 
that can be sanded and buffed if you want a really nice part or just lightly 
sanded and waxed.  The parts come out great!  And you can see how deeply the 
wax "soaks" up into the paint leaving it darker.  However, just plain wood 
releases beautifully when waxed and can leave a decent surface although some 
grain will come through.  One trick to eliminate that is to brush on a 
sanding "gelcoat" of epoxy.  All you have to do is mix a little micro 
balloons and fumed silica (Cabosil) together in about 25/75% volumetric 
ratios with the epoxy until it is just shy of being thixotropic, (leaving it 
just a tad runny will allow it to level itself a bit on the surface), then 
brush on to the surface.  Once stiffened up you can continue the lamination 
then when popped off of the plug, you can do some sanding without getting 
into the structure.  And if you don't go into the fibers and want to paint 
it, you can do so without the prime/sand step.

I always keep a gallon can of Featherfill in  my shop since I build a lot of 
molds and plugs.  I also keep around a few sheets of melamine finished 
particle board for plugs or molds since it is cheap and easy to work and 
requires no finishing in order to be ready to wax and laminate.  In fact just 
this last week I used both to build a keel trunk for my boat and will be 
using more for the new engine box.  Since these were all basically flat 
sided, I only used the Featherfill to finish the raw edges of the 
particleboard.  The parts came out perfect as if they were from a highly 
finished mold but in fact it was a one use, then toss away plug.  I've also 
used the melamine board as a mold for making flat cored panels.

Dan Newland