<VV> RE: Instrument Panel Lens

[John Dozsa]

Small quantities of the original pointed shape lens can be easily made
using vacuum forming techniques.  Basically a clear PETG copolyester
sheet is heated with a sun lamp until it droops over a mold.  The mold
is frequently made of wood and has a matrix of holes drilled in it.  The
holes are manifolded to a vacuum source.  As the drooping sheet touches
the mold the vacuum sucks the pliable plastic to shape of the mold. 
Manual moving of the heat lamp allows you to soften the plastic where
needed.  Think of what happens to the clear disposable bakery food
containers when you put them in the dishwasher.  They just droop from
the heating element.  It's the same idea except the softened plastic
takes the shape of the mold.  You can make a mold using bondo plastic
and the original lens coated with mold release.  The inlet side of a
garage air compressor will make more than enough vacuum when stored in a
receiver tank.

Trim the formed sheet as needed with a hot knife and apply lettering
with an artist's brush.

John 

> Message: 7
> From: JVHRoberts@aol.com
> Date: Mon, 22 Nov 2004 19:45:32 EST
> Subject: Re: <VV> RE: Instrument Panel Lens
> To: ncwitte@wittelaw.com, virtualvairs@corvair.org
> 
> The best way is to make a mold. Find a shop that does contract injection
> molding, and have them shoot a whole bunch. Aluminum would be fine, since we're
> not talking hundreds of thousands of lenses. You'd be surprised how cheap it
> would be, if you were intent on making a few hundred.
> 
> In a message dated 11/22/2004 6:01:53 PM Eastern Standard Time,
> ncwitte@wittelaw.com writes:
> On the question of how to make a replacement lens:  you would probably have
> to sacrifice having the nice pointy lens like the factory has, but you could
> make a new lens out of flat plexiglas, using the original part as a
> template.  Then I would do the math to convert from English to metric for
> the speedo, create a computer template for the hash marks and numbers, pick
> up a copy of Scale Auto Enthusiast and find a place to either have decals
> made or get decal stock to attach my numbers.  Get the decal made, clean the
> plexi carefully, use some solvaset and super sol or whatever the two little
> bottle are for setting decals (car modelers know about this stuff), and put
> my numbering on with decals.  Not sure how well this would work at night,
> though.  Another option from the model car world would be to have the
> numbers photoetched and attach them in the appropriate places with RC glue,
> but you would have to have a really steady hand and good eye to make that
> come out right.
> 
> Or you could CNC mill them out of a block of acrylic.  gggg
> 
> Norm Witte
> 
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