Tinted roof, help needed

[Ozruss90]

Got some scratches in my tinted roof, ranging from mild to severe. Took the roof to a high end car resto business to ask if it could be fixed. They asked if l could find out what the roof is made from, and how it’s made, so they can determine how to attack it. Don’t want to sand it if it’s going to go through some sort of coating. It’s the factory optioned tinted roof on my ‘90. #1948
Any help and adivise appreciated.
Cheers from down under.
Russell

[GOLDCYLON]

Got some scratches in my tinted roof, ranging from mild to severe. Took the roof to a high end car resto business to ask if it could be fixed. They asked if l could find out what the roof is made from, and how it’s made, so they can determine how to attack it. Don’t want to sand it if it’s going to go through some sort of coating. It’s the factory optioned tinted roof on my ‘90. #1948
Any help and adivise appreciated.
Cheers from down under.
Russell



Russell if it severe you may want to consider a relensing option or a new top. Maybe a Auto Detailer Professional that does high end cars can advise you but I'm thinking it will swirl and you wont be 100% happy with the end result. My thoughts GC

[aafc]

Hi.
Came across this youtube called C4 target top off scatches 2. It might be of use to you. Corvette masters in Orlando FL. did this to a top with scatches and
it worked.
Good luck
John
1990 black/white #2546
one of a few auto (4l8OE) EQ ZR-1's

[Ozruss90]

Thanks John,👍
Didn’t think to search you tube. Found a couple of clips that show it can be sanded. That’s what l was trying to establish, if it could be sanded without damaging the surface. Would still like to know what material the roof is made from, so l can tell people if they ask.
Cheers,

Russell

[RussMcB]

Not sure how bad yours is or how much you want to spend, but mine was bad (cracked, scratched) so I went for a replacement from Melrose and it sure is nice having a brand new roof (well, new plexiglass in my old frame).

[spork2367]

Thanks John,👍
Didn’t think to search you tube. Found a couple of clips that show it can be sanded. That’s what l was trying to establish, if it could be sanded without damaging the surface. Would still like to know what material the roof is made from, so l can tell people if they ask.
Cheers,

Russell

Almost all the tops of the time period were Plexiglass (trade name) acrylic sheet. Unlike Lexan (polycarbonate), acrylic is much harder and often doesn't use specialized coatings, which means it can be sanded. Doing that without getting low spots can be extremely difficult. So only the lightest scratches can be removed without resurfacing the entire surface.

Headlights in modern cars are made of polycarbonate which has long chain polymers that are much more impact resistant, however, it is much softer so they require specialized coatings. Over time those coatings wear away and the polycarbonate below discolors (due to poor UV resistance) and crazes. You can polish it, (with those headlight kits) but without the hard coating it will quickly go back to being hazy and discolored. They can only be new once. There are companies that can recoat them, but it is prohibitively expensive. The shop I used to work at machined and resold a lot of plastic, and we occasionally sent of sized sheets out for MR10 scratch resistant coatings.

[Ccmano]

Almost all the tops of the time period were Plexiglass (trade name) acrylic sheet. Unlike Lexan (polycarbonate), acrylic is much harder and often doesn't use specialized coatings, which means it can be sanded. Doing that without getting low spots can be extremely difficult. So only the lightest scratches can be removed without resurfacing the entire surface.

Headlights in modern cars are made of polycarbonate which has long chain polymers that are much more impact resistant, however, it is much softer so they require specialized coatings. Over time those coatings wear away and the polycarbonate below discolors (due to poor UV resistance) and crazes. You can polish it, (with those headlight kits) but without the hard coating it will quickly go back to being hazy and discolored. They can only be new once. There are companies that can recoat them, but it is prohibitively expensive. The shop I used to work at machined and resold a lot of plastic, and we occasionally sent of sized sheets out for MR10 scratch resistant coatings.

Hmmmm.. learn something new every day. Thanks Spork.
H
:cheers:

[WVZR-1]

My '90 'bronze top' has the manufacturers bug just off the rear edge and it's
AlmaCoat 2000®

https://trademark.trademarkia.com/almacoat-2000-73632571.html

There's much info out there on the WWW - ALMAC PLASTICS

There's a couple snapshots in this post

https://www.corvetteforum.com/forums/c4-general-discussion/3400600-original-glass-top-label.html#post1585861539

[Ozruss90]

Thanks you to those that responded. I’m sure some of the deeper scratches won’t come out but if I can get it 50+% better, I’d be happy to put it back on the car. Don’t know where I’d be, owning a ZR-1 without this forum. So much knowledge and willingness to help from other owners. Fantastic.
I will call into the shop where I left the roof and take some photos so I can post before and after shots.

[spork2367]

My '90 'bronze top' has the manufacturers bug just off the rear edge and it's
AlmaCoat 2000®

https://trademark.trademarkia.com/almacoat-2000-73632571.html

There's much info out there on the WWW - ALMAC PLASTICS

There's a couple snapshots in this post

https://www.corvetteforum.com/forums/c4-general-discussion/3400600-original-glass-top-label.html#post1585861539

From the other forum off an 87 top:

"ACRIVUE A"
"DOT 66 AS5"
"M-178 0757"
"ALMAC PLASTICS"

The Acrivue line included manufactured acrylic formed windows for planes and panels for cars.

The tops are likely manufactured similar to the windshields with the center layer being a colored mylar film layer which may have UV filters.

Acrivue A was likely aerospace grade poly A (ASTM D-4802).

The Almacoat 2000 is likely an upgraded aerospace grade poly 2000 (MIL-P-25690). It was more resistant to crazing and cracking than poly A.

The original could have been coated to give it better protection from gas, oil, and grease, but acrylic is very scratch and UV resistant on it's own, so buffing won't really affect longevity.

The problem tracking some of this info down is that so many plastics manufacturers have come and gone and they all used their own trade names for industry standard materials. US cast acrylic and European cast acrylic is high quality. China's sucks, India is marginal. I used to manufacture a lot of parts for GE Inspection Technologies that used acrylic blocks with complex geometry that we machined for ultrasonic test equipment.

[Ozruss90]

From the other forum off an 87 top:

"ACRIVUE A"
"DOT 66 AS5"
"M-178 0757"
"ALMAC PLASTICS"

The Acrivue line included manufactured acrylic formed windows for planes and panels for cars.

The tops are likely manufactured similar to the windshields with the center layer being a colored mylar film layer which may have UV filters.

Acrivue A was likely aerospace grade poly A (ASTM D-4802).
The Almacoat 2000 is likely an upgraded aerospace grade poly 2000 (MIL-P-25690). It was more resistant to crazing and cracking than poly A.

The original could have been coated to give it better protection from gas, oil, and grease, but acrylic is very scratch and UV resistant on it's own, so buffing won't really affect longevity.

The problem tracking some of this info down is that so many plastics manufacturers have come and gone and they all used their own trade names for industry standard materials. US cast acrylic and European cast acrylic is high quality. China's sucks, India is marginal. I used to manufacture a lot of parts for GE Inspection Technologies that used acrylic blocks with complex geometry that we machined for ultrasonic test equipment.


Thanks Spork,
A wealth of information on the subject matter.

Cheers,
Russell down under.