Helmsman spar urethane method

[stove937]

Have any of you tried this method of fixing up the plexiglass on headlights? I've heard the 50 - 50 ratio with mineral spirits. Also if anyone has tried this, if i really mess it up is it easy to remove? I plan on using this on aircraft windows if i get good feedback from you guys. Unfortunately, in this situation, its not cheaper to try than to replace, when ONE of these windows costs around 10 grand to replace. Anyways, i have no problem trying it on a smaller window, then having to remove it if it all goes terribly wrong.
For clarification, do you guys use the water based variety, or the oil based variety?

[Mike Phillips]

Just to clarify...

You want to paint your airplane's windows with Helmsman Spar Urethane?

Like prep the plastic and then either spray it or brush it on to hopefully restore clarity?


Most if not all headlights on modern cars are polycarbonate plastic, not Plexiglas. Near as I can tell not much of anything is made out of old-fashioned Plexiglas any longer.

Everything is either Polycarbonate Plastic or Lexan. Both of these are very hard and very shatter resistant but both also will scratch very easily.

I've never had any luck at all restoring a PERFECTLY clear surface to Lexan and I've buffed on a lot of Lexan. You can get it better than it is if it's really bad to start with but not what most Joe Consumer's would expect because most Joe Consumers have know idea how hard this material is and how UNPOLISHABE it is. Period.

Polycarbonate is very hard but it can be sanded and buffed fairly easy.

Plexiglas is the EASIEST plastic ever invented to work on as far as sanding and buffing or ANYTHING and that's why it's kind of sad to see it no longer being used for anything.

The windshield on my 1967 Starline Deville is Plexiglas and while it's in super condition for being 42 years old it has a few scuffs here and there and they'll polish out as easy as a summer breeze.

Because airplane windows are very expensive, you should find out first what the exact material is before attempting anything. If it's a newer plane then it's likely going to be Lexan, if it's an old classic from the 1950's, 1960's or 1970's and maybe even the 1980's then it's likely Plexiglas.

There's lots of plastic polishing kits on the market and we offer a number of options but before you touch your airplanes windows with anything you need to find out exactly what type of material you're working on.

[stove937]

I've decided to ditch the painting. I think that it's too risky. Anyways, I have confirmed that it is indeed lexan. I've read a few posts from you, mike on the meguiars forums when you had a rear window of a ferrari I think it was. You reported that you were going to try m105 on it. How did that go? My idea was to use m105 SIP then possibly final if needed.
Thanks,
William