I've used ethanol to help dye certain clear plastics. It definitely has
a penetrating effect. Looks like a shielded glass may be the way to go,
for sight gauges...
Jeff
ALAN YERLY wrote:
> Sorry I couldn't weigh in on the site lately, too much work and too
> little time.
>
> You can go to my website at customflightcreations.com and select
> accessories to see how I do my sight tubes. They all work very well
> between the seats.
>
> Back to ethanol... I finished a test on a 10% ethanol 92 octane fuel
> and its effects on our polyurethane tubing, and acrylic plexiglass.
>
> To my surprise, the ethanol fuel really made the polyurethane yellow
> faster. After prolonged exposure, the urethane did not seem to
> deteriorate at all. However, within two hours, the yellowing of the
> tube became pronounced. I frankly looked pretty dark after a week, but
> it was readable and held up well.
>
> I then tested it with a new rigid acrylic tube, which by the tech data,
> was supposed to be safe for use with gasoline, and fair with pure
> ethanol. After only two hours, the acrylic began to break down in the
> 10% fuel mixture. By the end of 8 hours it began become slightly opaque
> and slimy where the fuel contacted. I then cut a piece of the tubing
> and submerged it completely. Sure enough, the tube outer part became a
> slimy mess, but it was still rigid, although un-useable. So please
> pretest your acrylics.
>
> Redux (Epibond or Araldite 420 A/B) held up pretty well. The glue had
> cured for only 12 hours and was submersed. No significant change
> noticed. Pro Seal was OK but the manufacturer has only tested it to 10%
> ethanol in fuel, and I noticed a slightly slimy surface, but it still
> stuck very well with prolonged exposure.
>
> My lessons learned are to make the urethane sight tube easy to replace
> on the annual inspection and stick with the urethane tube. The FAA
> requires some sort of visual fuel check before flight, so it works for
> me. Plumbed the way I show it in my website, allows it to be useful in
> flight also. Electronically, I use the capacitance fuel probes for fuel
> measuring with a Mitchell or similar gauge and calibrate the probe at
> 0-5-10-and 15 gallons to correspond to the 1/4,1/2,3/4, full, points. I
> must admit, that changing the face of the gauge is the way to go. I do
> it in shop and should have Mitchell change the face on a custom order.
> They will do it for a price.
>
>
> Thought this may be of interest.
>
> Bud Yerly
> Custom Flight Creations
> (813) 653-4989
>
> *
>
>
> *
>
> Checked by AVG - http://www.avg.com
>
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