Restoring plastic windows

[Chris M]

The years have taken their toll on our 150's windows. They are blue, milky, hazy, and have chemical damage from some unknown event. I had a quick go at clearing a small area up today and while I was able to make it a lot shinier I didn't do much for the overall clarity. The process I followed was 4 wetsanding stages (1000, 1500, 2000, 3000), followed by medium and fine rubbing compounds on the outside of the window and polishing with both compounds on the inside.

Outside after:

IMG_20151116_122611.jpg (132.67 KiB) Viewed 2650 times

Inside after (refinished area is in the center of the picture):

IMG_20151116_122637.jpg (131.82 KiB) Viewed 2650 times

I think I could get some improvement with more aggressive refinishing of the interior surface but I don't know how much.

Any suggestions on bringing these back to life or have they pretty much kicked the bucket at this point?

[Heliian]

How much is your time worth? New plastic isn't that cheap but will give you a nice clear view for at least a year. Just keep buffing it if you want. Micromesh is the branded system which is similar to what you're doing but may be finer in the end. Best of luck

[7ECA]

Maybe give https://www.aircraftspruce.ca/catalog/c ... leaner.php a try, seems to work pretty well on most flight school aircraft, even helps a bit with light/moderate crazing due to overzealous students with circular wiping patterns...

But at some point you'll have to consider how much time you want to spend working at it, versus the cost of replacing the windows.

[aviatrix444]

I had the same issue on my Cherokee. I tried everything, and some sanding/polishing/ chemicals made it better, but still not good enough. It became opaque with the sun shining through it. I sucked it up and bought new plastic, and it wasn't nearly as pricey as I was expecting, and it took all of an afternoon to replace when it arrived. Well worth the money.

One of the old ame's I talked to said over time the plastic actually starts to break down / delaminate on the inside of the pane, so no amount of elbow grease can fix it up again, which is probably where you're at unfortunately.

Ordered from Great Lakes Aero Products.

[plhought]

You're not taking off enough material starting with 1000.

I've done windows on an vacuum rig starting off with 180, to 240, then 1000, then I think 3000?...then 15 micron to 5 micron. Finish off with a 2 step plastic finishing/polishing compound. Some 3M product can't remember.

Wet-sanding throughout of course.

Worked great.

[Chris M]

You're not taking off enough material starting with 1000.

I've done windows on an vacuum rig starting off with 180, to 240, then 1000, then I think 3000?...then 15 micron to 5 micron. Finish off with a 2 step plastic finishing/polishing compound. Some 3M product can't remember.

Wet-sanding throughout of course.

Worked great.

180?! That's a lot of wetsanding.

*grabs belt sander*

[2R]

Big sheepskin buff and 210 ,the liquid bottle to get rid of scratches and the spray to clean.
The trick is to use lots of 210 and do not press too hard ,let the buffer float on the 210.
It does not take long to get rid of surface scratches ,
Any opaqueness and it is safer to replace .
The point is to enjoy the view ,take five minutes to show the new guy/gals how to protect the windscreen with a soft clean cloth.

[PilotDAR]

Honestly, 'been there, done that, and I would not bother again for anything other than local damage (a scuff). I used a MicroMesh kit, and it worked very well for scuff type damage, but it will not remove the milkiness, nor stress cracks/crazing which forms over years. Everything has a life, including windows. New Cessna windows are not terribly expensive, if I have to invest, I'd rather replace a crazed window than go to all that sanding/polishing effort to make it only a little better....