Making plastic parts

"cavelamb himself" wrote in message
...
Peter Dohm wrote:
"cavelamb himself" wrote in message
...

Peter Dohm wrote:

Actually, I did have a car a while back with one of those rear window

brake

lights that eventually failed. For no obvious reason, the replacement

bulb

(of the same physical size and generic part number) quickly burned

through

the top of the plastic casing--despite having a peice of foil (which
was
original equipment) directly above the bulb. That was also in the 1amp
range at 12-14 volts; but I believe that the clearance was closer to a
quarter inch.

A strobe should generate much less heat, especially localized heat,
than

an

incandescent bulb; but this is a good problem to keep in mind for nav
lights. Of course, LEDs have become an affordable and reliable

alternative

that also eliminate much of the heating problem--especially if the

current

source is remotely located.

Peter



Peter,

I just happened to have the plug and one of the "experiments" on hand.

Guess I need to revise the clearance question to LESS than 1/2 inch.

This one, I believe, is polycarbinate (DUE TO THE LACK OF BUBBLES IN THE
PLASTIC).

The lexan attempts were made with .065 scrap from my windshield.
Every one of those bubbled like crazy in the baking phase.

Lexan is hydroscopic and retains considerable water.
This stuff "boils" out while heating unless "baked" out at below 212
for several hours. It was kinda pretty with the colored light on inside
it. But not exactly the sleek smooth aircraft parts I had in mind...

Pic at:
http://www.home.earthlink.net/~cavel...sc.htm#wingtip

More clearance, thicker plastic, maybe they use some kind of special
stuff - I really dunno there.

Just that thin stuff with a fairly hot bulb simply didn't work...

YMMV

Richard


I am not really sure why, but I was thinking of the type of lens that
ends
up being an entire corner of a wing, so that it has a lot of volume and
a
lot of area. Now that I have thought about it, 12 to 14 watts is a
*lot* of
heat for this size lens.

I am not sure what material is used in the currently offered commercial
assemblies, but it may very well be glass. (As you might guess, I also
don't know what material to use as a mold for glass--much less how to
form
the resulting mold.)

Peter




Well, I think we know it has been done before.
I know I've seen those corner style covers.

But the details?

Might be I was just too close and too thin for the amount of heat.

Continue researching this, Peter.

Like my Ex was fond of saying..."Three weeks in the lab will save you
4 days in the library every time".

Richard

It really is always Hell, when anyone's Ex was right...

Peter

"Peter Dohm" wrote in message
. ..

(snipped over 100 lines of text)

It really is always Hell, when anyone's Ex was right...

Peter

(For a 2 line reply.)

Peter ......

I encourage you to *please* snip the excess lines from your reply.

Thanks for your consideration,
Rich S.

Wait a minute....wait...wait...oh yes, I do recall that time! Somewhere
about when I joined up back in 1980 or so


Scott
http://corbenflyer.tripod.com/
Gotta Fly or Gonna Die
Building RV-4 (Super Slow Build Version)


cavelamb himself wrote:
Scott wrote:

What!?!? The Expensive Aircraft Association was once about
homebuilts?


way back in once upon a time time...

--

On Mon, 03 Sep 2007 04:34:02 -0700, Lou wrote:

Does anyone know of a material that starts as a liquid, but hardens as
a platic?
I want to make some custom plastic parts for my plane (no not for the
structure)
that will require making a mold and then pouring in the liquid.
Lou

Check this out.

http://www.reynoldsam.com/

--Andy Asberry--
------Texas-----

We use ECCO self-contained strobes on aerial ladders for firetrucks where I
work, and they seem to work well and I believe they are a lot cheaper than
Whelen. Check out their web page, perhaps you can find something that might
be useable on your airplane. In particular check out their 9001 series,
those look like they might be adaptable to an aircraft wingtip. They aren't
self contained though, you'd need an external strobe pack (power supply).
I don't remember the model number since I left the aerial ladder
department almost five years ago, but we use some strobes that are
completely self-contained, all you had to hook up was 12VDC and ground,
the power supply is built right into the mounting base. Those lights were
maybe 3 inches in diameter at the mounting base. I believe you could
probably figure out a way to put those in your wingtips too. Let me know
if those sound like something you'd be interested in and I'll try to find
out the model number and price when I go back to work Monday.

http://www.eccolink.com/ProductPages/Products.cfm

Scott Wilson