Wrinkles and plastic surgery

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JohnGreenview
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Joined: Thu Nov 25, 2010 4:28 pm
Location: Whiting Bay Arran

Wrinkles and plastic surgery

Post by JohnGreenview » Wed Jul 05, 2017 6:37 pm

Hi

The aesthete in me decided to try and remove some of the scratches in my Tiderace Explore X. It is all red with black on hull front and rear. Being coloured the scratches on my the hull tend to show up. They tend to look white though I don't think the gel coat is compromised.

Anyway, reading a little on line, I decided to try some 320 wet and dry to tone down and hopefully remove them. There does not seem to have been any improvement but more particularly, some of the areas sanded have gone dull. This is particularly noticeable in the black areas. The gloss black finish has become a kind of dull milky grey.

Any suggestions for salvaging this would be welcome.

I noticed one YouTube video sprayed over the scratches with a clear enamel gloss spray. It seemed to be effective. Any thoughts on this.

Yes, I know, I shouldn't have touched the scratches and just embaced them like I do my wrinkles, but I didn't, and there is a part of me likes to restore to the pristine... if I can.

PS. I'm away for a few days so any comments won't receive from me an immediate response.

Irish Sea
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Re: Wrinkles and plastic surgery

Post by Irish Sea » Wed Jul 05, 2017 6:52 pm

You got to go through several finer grits on your sandpaper and then finish off with some polishing compound.

john.ruston
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Re: Wrinkles and plastic surgery

Post by john.ruston » Wed Jul 05, 2017 9:56 pm

Abrasive paper (use wet perhaps with a hint of Fairy liquid as a cutting fluid) wrapped round a rubbing block (get from car bodywork suppliers) gives you a flat surface. As said above use a progression of ever finer papers - don't dismiss the worn papers they can get superfine. Common sense will tell you when you've cut back far enough. Then put a rag over your fingertip and after dipping it in a splash of Brasso, T-Kut or similar --
polish gently with circular motion until you have a dry 'bloom' . Have fine cloth handy to dust it all off. Should be like a mirror. If doing a big area you can buy or hire an electric pushing tool to save elbow-grease. Its the same a producing a quality surface when repairing car bodywork. If in doubt - dont touch it and ask an expert.

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Jim
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Re: Wrinkles and plastic surgery

Post by Jim » Wed Jul 05, 2017 11:10 pm

320 is too coarse, don't go more than 400 in future!
Use a block for even pressure and sand wet as already advised.
Sand linearly, back and forth in the same direction so all the scratches from the abrasive are paralell and easy to make out.
Change to the next grade of paper (600-800-1000-finer if available), and sand linearly perpendicular to the last grade. Sand until you can;t see any 400 grit scratches only the smaller 600 grit scratches.
Continue changing orientartion each time you change grade.
1500 or 1600 is a common fine grade, I also have 1200, 2000 and 2500 but they are harder to find and don't really do much in the finer grades (often the abrasive comes off after just a few rubs). Once you get to 1000 you can switch to polishing but any finer grades you can use will make the polishing a bit easier.
Use a proper fibreglass polishing compound, any yacht chandlers will have some. Personally I polish wet to reduce the chance of generating friction and making the gel hot - spray the hull with an atomiser spray periodically whilst polishing. Polishing by hand is possible but laborious, using a polisher gets a better result more quickly (patience or lack of prevents hand polishing getting perfect finish) - electric ones are most common but I use an air powered one (needs a lot of air, big compressor). A polisher looks like an angle grinder, but is a lot slower and is usually fitted with foam backing pad with velcro to stick a foam polishing head to - an angle grinder will overheat the gel coat so don't improvise.

If I remember I will try to take some photos of my partially polished river racer at the weekend before I finish polishing it, the contrast between the old faded matt gel coat and the recently polished much deeper coloured shiny gel coat should come out well.
I say finish polishing it, that boat has had all the hull gel coat and other layers of mess that were on top stripped off, extensive repairs and the hull has then been coated with a UV stable epoxy, sanded nearly smooth, wet and dried and polished whilst the deck has had some repairs and has been wet and dried and polished - at some point I may try to smooth the hull out some more (it is so much better than when I got it that this is not a priority) and polish it again, the deck has some repairs for which I used the wrong colour pigment so I might sand them back again and repair with the right shade (it is unlikely to be a perfect match but will be much closer) and also flow coat over some areas where the gel is thin, in which case I will end up sanding and polishing some more, but for now I just want to get the original colour of the main deck to look even all over....

JohnGreenview
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Location: Whiting Bay Arran

Re: Wrinkles and plastic surgery

Post by JohnGreenview » Thu Jul 06, 2017 3:31 am

Many thanks for helpful comments.

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