Polishing windshield

[AndreiC]

Somehow, I don’t know how, I managed to put an unpleasant scratch in my windshield. It is an area of maybe 1/2” x 1/2” that is now hazy, and if you feel it with your finger you can clearly feel it’s not smooth (it’s on the outside).

Can something like this be polished out without messing up the whole windshield? I can live with it as it is, but it is in my field of vision and it will bother me every time I fly. But replacing the whole windshield (which probably is at least a 1 AMU endeavor, if not more) sounds stupid for such a small scratch. 

I was hoping that maybe the kind of treatment that removes haze from car headlights would fix it. But I don’t know if it works, if it does not make it worse, and if I can do it in just one localized spot or if I need to polish the whole windshield. 

[PT20J]

Try Novus plastic polish. Micro-mesh if it's too deep for the Novus. Work a much larger area than the defect to blend repair so that you don't created a wavy spot. 

https://www.amazon.com/NOVUS-PK1-8OZ-PM-Plastic-Scratch-Remover-Bottles/dp/B0029B518O/ref=sr_1_5?crid=2ACXNZG8Q3I5U&dib=eyJ2IjoiMSJ9.xhC6gaULd5ZtKOfVkF6ulyiuvtq03bY7QVM0_Fixf6ferCEsiVxOEt-l_I_3hc-336uyx_fTgst-lAti01_aS2PBia9s67VUGwORbrZpm37bTtCF96Qi9j_j1K3b6KYcAPwaEHFQPfWhh1eJCMLQ37UI0vzmAeaOoboDEebZ21p19dE37utUg-ARE194AqsOi4PCb8xw8LhoDfCEdOW9qh4CxLvnpvc0HxnmYp16KnOfg3VGh8AozNcvpleDAgeI079bY4dTzCkefTZRR2_qZKmNC1FXqG1787W7wTvbn8VtLIV-BZwQmy5mVAgxD4DkLeUd5UA0DE8pY4BlrDon3yze8SrfiviT3mV-ilWHNJG0ognKrfKTpY02-WC6w8Z_kXJs5b5tcsYAYFR3WC62CtKNVuCN95gQEUhyawnjA095vZ0uAePmHD6yLeO_5Fhq.S_2wUyXcF0u5aeDXwxq7k8j0mhJu4Ax_f3Ea1i0pxZ0&dib_tag=se&keywords=novus&qid=1734479554&sprefix=novus%2Caps%2C198&sr=8-5

https://www.aircraftspruce.com/catalog/cspages/micromeshstd.php?clickkey=11681

[IvanP]

I used the polish kit from Spruce on mine and it worked quite well.  

https://www.aircraftspruce.com/catalog/cspages/scratchoff.php 

 

[Hank]

13 hours ago, PT20J said:

Try Novus plastic polish. Micro-mesh if it's too deep for the Novus. Work a much larger area than the defect to blend repair so that you don't created a wavy spot. 

This means to polish an area about 6" x 6" for your scratch. Polish deeply around the scratch, and fade it out to at least this size.

EDIT:  back when I used to polish steel, each grit would cover a larger area (to eliminate the "edge"), and for a 1" long scratch, the final polish was often nearly a foot long and several inches wide. This should work for your window, too.

[MikeOH]

24 minutes ago, IvanP said:

I used the polish kit from Spruce on mine and it worked quite well.  

https://www.aircraftspruce.com/catalog/cspages/scratchoff.php 

 

Thanks for the PIREP!  I purchased the kit a couple of years ago but have been too chicken to give it a try!

[IvanP]

I think it is a good kit. It was a bit of work, but worth it. Someone managed to make some pretty substantial marks on the inside of my windshied, probably when doing avionics work before I bought the plane. I polished all the windows in less than a day (both sides on winsheild and outside only on the rest (overspray from painting, etc.). I used small Proxxon angle polisher and that made it a bit easier to work on the inside. If you plan on using rotary tool, I suggest slow speeds and apply compounds sparingly, otherwise you will have the polishing compunds all over the place (ask how I know  ). They are pretty thin liquids. It can be done by hand, but that would involve a lot of elbow grease. I did not take and before and after pics, but I am satisified with the results, despite being quite picky when it comes to maintenace of my plane.    

[0TreeLemur]

If you can feel a scratch with your fingernail, you cannot polish it out without altering the optics of your windshield.

Auto detailers removing deep scratches in plexiglas windows will use a random orbital sander with sandpaper to remove material over the entire window to the depth of the scratch, then use successively finer polishes/pads to clear the window up.    There is a good video on youtube that shows exactly how to do it.  The problem with this is approach is that it makes the window thinner, probably not good for an aircraft windshield.  I did use this approach to remove a couple of deep scratches from one of my side windows and it worked like a charm.  It took guts to apply sandpaper to the window and it looked like holy hell after I went over it.   But the Novus polish system cleared it using a finishing pad on the random orbital.

After that I used the Novus system and finishing pad to polish all my windows, including the windshield.   Aside from that one deep scratch it looks new.   Luckily that deep scratch is on the co-pilot's side and easy for me to ignore.

[Ragsf15e]

Sorry to revive this, but I’m going to put together the supplies to attempt some work on my windshield. You can’t catch a finger nail in any of the scratches but it’s been marked up pretty good both on the inside and the outside. Especially where the instrument panel cover has been taken in and out. I have Novus 1, 2 and 3 and those don’t seem too aggressive. Does anyone have a good recommendation for an angle polisher with an adjustable head? And what kind of foam cushion should I use on it?

[N201MKTurbo]

You know the kits that are for polishing out your headlights will do wonders for your windshield.

[Ragsf15e]

46 minutes ago, N201MKTurbo said:

You know the kits that are for polishing out your headlights will do wonders for your windshield.

Yeah, the novus works reasonably well too but I need to find some kind of an orbital polisher to get inside the windscreen, especially low, close to the glare shield.  It’s really hard to put any oomf into it by hand there.

[N201MKTurbo]

9 hours ago, Ragsf15e said:

Yeah, the novus works reasonably well too but I need to find some kind of an orbital polisher to get inside the windscreen, especially low, close to the glare shield.  It’s really hard to put any oomf into it by hand there.

I hate that place. My only advice is to remove the glare shield to get better access, but I’m sure you already knew that.

[N201MKTurbo]

https://www.acehardware.com/departments/tools/power-tools/rotary-tools/2823730

 

[PT20J]

10 hours ago, Ragsf15e said:

Yeah, the novus works reasonably well too but I need to find some kind of an orbital polisher to get inside the windscreen, especially low, close to the glare shield.  It’s really hard to put any oomf into it by hand there.

I did the lower inside of mine by hand with Novus, but it took a long time and mine wasn’t too bad. I would try Micro-Mesh which is a kit of several progressively finer grits of sandpaper. I used it to remove scratches on the side windows of my previous plane and it was pretty fast. I believe Mooney puts teflon tape on the edge of the glares shield which I replaced, but I found that it still scratches the windshield so I put some window trim edging on it.

[Ragsf15e]

2 hours ago, PT20J said:

I did the lower inside of mine by hand with Novus, but it took a long time and mine wasn’t too bad. I would try Micro-Mesh which is a kit of several progressively finer grits of sandpaper. I used it to remove scratches on the side windows of my previous plane and it was pretty fast. I believe Mooney puts teflon tape on the edge of the glares shield which I replaced, but I found that it still scratches the windshield so I put some window trim edging on it.

Did the glareshield still fit ok?  Mine seems pretty tight and I don’t think there’s anything along the back protecting the window (which looks bad there).

Also when you take out the glareshield do you take off the trim pieces between the front and side windows?  Those seem to block complete removal.

[PT20J]

9 minutes ago, Ragsf15e said:

Did the glareshield still fit ok?  Mine seems pretty tight and I don’t think there’s anything along the back protecting the window (which looks bad there).

Also when you take out the glareshield do you take off the trim pieces between the front and side windows?  Those seem to block complete removal.

The glareshield on my 1994 J is a royal pain to remove. The one on my 1978 (without the hump in the center) was a breeze. You are right that it is a tight fit and most of the u-channel I found is too thick. My painter buys his from Textron because Cessna uses it and it's the only source he's found for it. But, I think the silicone window beading that Jaeger sells would work as it's pretty thin.

I use a couple of tricks I picked up from other MS posts when removing my glareshield. First, I remove the compass from the center post. Then, after removing the glareshield screws, I slip a couple of thin plastic sheets on either side between the A pillars and the glareshield to make it slide more easily. Lastly, I lift the front edge up towards the top of the windshield and pull rearward which seems to give the most clearance with the least flexing of the plastic.

[Paul Thomas]

8 hours ago, PT20J said:

The glareshield on my 1994 J is a royal pain to remove. The one on my 1978 (without the hump in the center) was a breeze. You are right that it is a tight fit and most of the u-channel I found is too thick. My painter buys his from Textron because Cessna uses it and it's the only source he's found for it. But, I think the silicone window beading that Jaeger sells would work as it's pretty thin.

I use a couple of tricks I picked up from other MS posts when removing my glareshield. First, I remove the compass from the center post. Then, after removing the glareshield screws, I slip a couple of thin plastic sheets on either side between the A pillars and the glareshield to make it slide more easily. Lastly, I lift the front edge up towards the top of the windshield and pull rearward which seems to give the most clearance with the least flexing of the plastic.

Jaeger no longer sells it; they've lost their supplier. Vantage has some and this MM Seal looks to be an option
https://mmseals.com/collections/edge-trim/products/gray-edge-trim-standard-size-u-extrusion-u-height-17-32-grip-range-3-64-9-64

[Slick Nick]

9 hours ago, PT20J said:

The glareshield on my 1994 J is a royal pain to remove. The one on my 1978 (without the hump in the center) was a breeze. You are right that it is a tight fit and most of the u-channel I found is too thick. My painter buys his from Textron because Cessna uses it and it's the only source he's found for it. But, I think the silicone window beading that Jaeger sells would work as it's pretty thin.

I use a couple of tricks I picked up from other MS posts when removing my glareshield. First, I remove the compass from the center post. Then, after removing the glareshield screws, I slip a couple of thin plastic sheets on either side between the A pillars and the glareshield to make it slide more easily. Lastly, I lift the front edge up towards the top of the windshield and pull rearward which seems to give the most clearance with the least flexing of the plastic.

Have you got the “bravo” style glareshield in your MSE? I thought that didn’t come out until the Allegro in ‘96?

My ‘91 isn’t bad to remove. I do put some gaffer tape on the center post to avoid scratching it, but otherwise remove the two screws, disconnect the glareshield lighting, and pull straight back while bending it at the seam in the center. Slides right out no problem. 

[PT20J]

1 hour ago, Paul Thomas said:

Jaeger no longer sells it; they've lost their supplier. Vantage has some and this MM Seal looks to be an option
https://mmseals.com/collections/edge-trim/products/gray-edge-trim-standard-size-u-extrusion-u-height-17-32-grip-range-3-64-9-64

I believe that's Trim Loc which is pretty thick. I haven't tried this, but I think it's a possibility https://www.glapinc.com/Cessna/misc/misc.htm

[Ragsf15e]

2 hours ago, PT20J said:

I believe that's Trim Loc which is pretty thick. I haven't tried this, but I think it's a possibility https://www.glapinc.com/Cessna/misc/misc.htm

I also looked up Brown Aircraft you mentioned in another thread and thought this might work on the back of the glareshield. It’s pretty small.

https://www.brownaircraft.com/Black-Trim-Lok-Edge-Trim-1-64in-by-3-8in-p/trim-lock-0-b.htm