From: Fredmoreno@aol.com
Message-ID: <43d40f31.2514856b@aol.com>
Date: Sat, 18 Sep 1999 02:04:27 EDT
Subject: Suggestions for window tinting?
To: lancair.list@olsusa.com
Mime-Version: 1.0

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Marv:

Given the evident knowledge you and others have about additives, tints, 
coatings etc. to block unwanted UV, can our assembled group make a 
recommendation for a tint to minimize heating in our Lancairs?  I was 
recently in a new Ford Crown Victoria rental car, and was impressed by the 
minimal heating suffered when locked up in the sun.  There must be something 
on the glass that is bouncing the infrared off with high effectiveness.  What 
is recommended for the acrylic in our windows to keep us from from roasting 
in our cockpits?

I remain, well done, Fred


[It is possible that the windows in that Crown Vic utilized a pyrolitic
low-E coating to assist with solar heat gain, but unfortunately that 
process isn't applicable to plastics.  Rather than being an actual coating,
per se, one surface of the glass has been molecularly impregnated with
another material during the float process to give it the  particular low-E
characteristics desired.  In essence the coating _is_ the surface of the
glass.  That's why it's tough enough to survive in a monolithic (single
pane) application.  The hi-perf low-E coatings that are applied using 
the MSVD (magnetron sputtered vapor deposition) process are actually only a
few atoms thick and are relatively soft and susceptible to scratching... 
this is why those products may only be used in an insulated glass unit, 
with the coatings facing the airspace between the 2 panes of glass.
Besides the fact that they are soft they are really expensive to apply
and the machinery that is used in my industry is designed for flat glass
panels, as opposed to shaped materials.  I'll check with one of the
equipment companies on Monday, as I've got a contract with them to set up
some equipment and need to talk to them anyway... perhaps they know of
someone in the business who could deal with a canopy-shaped product and
would be willing to coat them on a contract basis.  I do suspect that the
cost will be prohibitive and fear that the only way to protect the
coating once it's applied would be to apply an additional plastic clear
coat which could cause optical problems.

In general, the cheapest and easiest way to fight the solar heat gain
battle with a plastic product is to apply a tint and reduce the total light
transmission, or start out with a solar grey tint in the first place.  The
medium grey tint probably passes 80% of visible light and the deeper 
grey tint probably passes about 50-60% of visible as well as the other 
invisible wavelengths.  I'll do the research regarding the hi-perf
coatings first of the week and report back with my findings.  <Marv>    ]

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