TEN-99

Anyone have any experience polishing or wet sanding out the swirl marks and peeleing silicone layer on one of these?

I have heard about it being done and just wanted to know if anyone has actually done this and could give me some tips.

Thanks in advance.

Billdog350

I'd be interested in hearing if this works too. I was thinking of trying to do it on mine, and if I screwed it up badly and couldn't recover the finish, just painting it body color and buying another one....if I do it, I'll keep you posted.

BLOWNZO6

Sorry you are out of luck.

Once the coating starts to fail you are done. Once the coating has also failed it will start to degrade the PC as well. There is nothing you can do to it.

You will not have any long term luck painting the silicone coating either. If you sanded enough to get ALL of the coating off, the paint will stick to the PC, but it will probably no last long. When I say ALL of the coating.. I mean all of it. The primer is acrylate based and the top coat is silicone.

m-nelson

I have found a partial solution for the classic problems with the transparent glass roof for the C5. These often have their hard, outer coating peel off. The damage is always a stripe on the passenger side running front to back.

There are 2 steps:

1.) Wet-sand the affected area with 2000 grit wet-dry paper. Sand until the edges of the coating are feathered out.

2.) Polish with lamb's wool pad on an automotive polishing machine or a smaller pad in a power drill. Use a very fine compound like 3M's that is meant for hand-glazing.

While not perfect, the roof's appearance is easily ten times better than the dull blotchy stripe you started with.

One other thought on paint..... I did try shooting clear over a small area of the defect & it looks like it takes paint just fine & hides/blends the defect away. As to paint adhesion, it was quite hard to get the material back off so I think adhesion is likely to be good. I'm seriously thinking of sanding the entire surface & shooting the entire thing with clear this spring.

One other point of clarification.... I'm not sure why people have been referring to the coating as "silicone", which is a fairly soft polymer. This material is more glass like. In fact its quite hard, so I doubt it's silicone based at all.

Mike

BLOWNZO6

The coating is in fact siloxane based. It is applied to the PC for both scratch resistance and weatherability.

GE Silicones AS4700 with SHP470 Primer.

We use damn near a million dollars of it and AS4000 per year.

If you take ANYTHING abrasive to it at all.. all you are doing is accelerating its wear. You will make it look temporarily better.. but once it starts microcracking and hazing.. it is done.

Billdog350

BlownZ, assuming someone could find the right type of clearcoat (possibly even more of that silicone top coat), why wouldn't it help? Assuming you can get it to stick, I would think that the extra layer of clear would really help.

Oh well, I heard that you can claim on your glass coverage on your insurance policy if you accidentally "drop" your roof when you're removing it or installing it....I think I might have an accident this summer.

m-nelson

BLOWNZO6,

Do you have any reason to think that a typical urethane clear-coat will not stick? The quick experiment I tried sure looked promissing. I didn't let the stuff set up fully, but it was still a bitch to get off. I needed acetone & a lot of rubbing.

In another post today; jrose7004 reports taht he has a year-old paint job on top pf the lexan roof.

Mike

Billdog350

What we should probably do is track what prep and paint people are using to get paint to stick to the lexan roof. I'm sure there is SOMETHING out there that will lay down and look good....

TEN-99

Hell, for the cost of that, prep, primer, painting, i'll just buy a hard top already painted off of ebay for $400.
I really could care less about being able to see through the roof. If I want to do that....I'll just take the thing off!!

I didnt think there was going to be an easy quick answer, because I see too many of these that look as crappy as mine.

I appreciate all the comments and input and I will keep checking back to see if some miricle cure shows up.

Thanks again......

Oldvetter

I have the dreaded "stripe" on my 1998. Recently after all the discussion about the silicone coating on these tops, I applied some diaelectric grease to the area, left it on a couple of hours and wiped it off. It has made it a lot less noticeable.

korvette4u

don't want to hijack this thread ,but is it possible to repair lexan? i have two stress cracks and would like to know?

vizette

My 2 cents since i just went through this...

I took the time to sand mine down with a palm sander to see if i could get a body shop to finish sand it and shoot it clear. The short version of the story is, i ended up getting it painted black.

The long version is, they said that if you just shoot it with straight clear you're going to run into issues, like durability and possibly seeing sanding marks, and that you really need an adhesion promoter. FWIW I did a test spot before taking it to them with canned clear, and it looked OK, so i figured they could make it look better than i ever could...

Anyway, they did have a relatively new adhesion promoter that was clear, and they offered to experiment with it if i wanted to pay for the time and materials, but the whole object was to save $ so i just had them do it in black.

Oldvetter

-How long ago did you get your top painted black and how has it held up?

C5forFun

A specialty shop in town that works on a lot of Corvettes also told me they have had good luck with wet sanding the coating completely off and polishing it. They told me I would not be able to tell the difference with the coating gone as far as the tint. They have one that was done a few years ago and said it has held up very well. I have not seen it myself, it is on a customers car.

thevelvetglove

Against the avice of the forum I took a chance and painted mine Torch RED to get rid of the stripe. It has been two months, and under the clear coat I think I can see some hazing. Not sure, but I'll keep you guys appraised. By the way the initial paint job came out great and cost $375.00.

TVROguy

I agree with you TEN-99, I could care less whether I can see through it or not ... Where can we buy a "hard top" (mine's a white 99)?
And, does it cut down on some of the air & road noise?

PGann

I stripped the glaze off mine and buffed the Lexan as others describe. Lots of work... not for the faint of heart. Took most of a day and a half.

Results were very good. Top looks better than before, even better than the best areas of the "before" top. No more spider cracking look on the inside. Outside still has original blackish look.

The key to getting good results is to get the glaze off without scratching the Lexan too bad. Deep scratches are a challenge to sand out. The catch is you have to use something fairly aggressive to cut the glaze. Sheet rock sanding screen works good. Follow with 400 grit, 800 grit and 1000 grit wet sand. Then buff out with a good power polisher with a wool pad. I used Maguiar's polish. The fine sanding prep is really important to get the best results from the buff.

quimbo

Follow this link this product works

http://www.racerpartswholesale.com/long25.htm



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