Sanding a mile of scratches

Discussion in 'Laser Talk' started by bjmoose, Nov 19, 2007.

  1. bjmoose

    bjmoose Member

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    Before sanding out, the color match looks good...
     

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  2. bjmoose

    bjmoose Member

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    Gelcoat doesn't cure in air. You must cover it. At first I tried spraying on mold release agent.

    But it was a lot easier and came out a lot better to cover the gelcoat repairs with wax paper held in place with painter's tape.
     

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  3. bjmoose

    bjmoose Member

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    Filling a scratch:
     

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  4. bjmoose

    bjmoose Member

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    Here's what the first round of fills looked like after removing the wax paper:
     

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  5. bjmoose

    bjmoose Member

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    Here's the technique for covering a scratch or filled area with paper.

    The first covers of the trailer dents with the mold release agent came out very poorly -- by the time they were sanded flush/flat/smooth the gelcoat was pretty much gone. So I reapplied those areas, as well as many more scratches in the second pass
     

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  6. bjmoose

    bjmoose Member

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    Here's the result of sanding out a gelcoat scratch fill. In the second pic, I've wiped away the dust with acetone. It looks pretty good though you can see the color match isn't perfect. At this point I'm pretty happy with my work...
     

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  7. bjmoose

    bjmoose Member

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    Wax papering the boat after the second round of scratch filling. You can see I had to do a lot of work in the bow area.
     

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  8. bjmoose

    bjmoose Member

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    Now I've sanded down the whole boat again with 60 grit, to smooth all the gelcoat repairs and sand out all the scratches that I didn't fill. That made the work go reasonably fast (still took hours) but using 60 grit for this second sanding will turn out to have been a mistake...
     

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  9. bjmoose

    bjmoose Member

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    Now I've wiped down the boat with acetone. You can see in some areas the gelgoat's gone thin on me. Actually, at the mast step I've sanded right through it.
     

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  10. bjmoose

    bjmoose Member

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    In this pic, I've started the next finer course of sandpaper, 100, etc... But I now can't afford to remove enough gelcoat to take out the sanding swirls left by the 60 grit sandpaper:
     

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  11. bjmoose

    bjmoose Member

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    Cutting my losses, I resumed sanding with either 240 or 320, then sanded through 800 and stopped. No point ing going on to 1200 as we can't get to perfect anyway.
     

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  12. bjmoose

    bjmoose Member

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    Time to go the rubbing compound. These photos show various repairs after they've been rubbed out. In two photos you can really see the swirls.
     

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  13. bjmoose

    bjmoose Member

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    The trunk, and more fill details. Damn swirls.
     

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  14. bjmoose

    bjmoose Member

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    Nice and shiney after two coats of wax. Yes I used a good auto wax. Let's save the whole "slow-surface-tension-inducing-wax vs. high-speed-non-beading-teflon-boat-speed-polish" for another thread, OK?
     

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  15. bjmoose

    bjmoose Member

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    A couple pix of deck repairs. When going for an "off white" repair, take care not to add too much color, as it's hard to "go back." I ended up with a little too much yellow.

    My deck sequence was:

    1. Clean. I used marykate on-and-off which is slightly too caustic to be used as a drain-clog-remover ;-)

    http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/264455/377%20710/0/marykate/Primary%20Search/mode%20matchallpartial/0/0?N=377%20710&Ne=0&Ntt=marykate&Ntk=Primary%20Search&Ntx=mode%20matchallpartial&Nao=0&Ns=0&keyword=marykate&isLTokenURL=true&storeNum=33&subdeptNum=299&classNum=299

    2. Remove tree-sap polka-dots. Drops of tree sap fell at some point and resisted all forms of chemical removal. I finally removed them with a tiny wire brush mounted in a dremel. I could do this on smooth gelcoat without marring it, but on the non-skid a few tiny scratches remained -- still not as bad as the original tree-sap-nodules.

    3. Fill. I had lots of fair size nicks and gouges, especially at the "tie down" points; for a while the boat was tied to the trailer with a fairly thin line. This ended up being a place where chips formed. Also, the docks at shoreline lake have pads that are too high to strike the laser gunwales. It turns out to be a LOT easier to use gel-coat PASTE, as it will stay in place on a vertical surface.

    4. Sand. Only enough to smooth the gelcoat patch repairs.

    5. Rubbing compound. I did the whole deck, including non-skid.

    6. Wax. Again two coats. Whole deck, including non-skid. Yes, it's more slippery than it was before. I think that's going to be OK. I've actually found that my wetsuit doesn't slide on the deck as easily as I'd like it to.
     

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  16. bjmoose

    bjmoose Member

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    Finished at last! Is it sailing season yet?
     

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  17. Chainsaw

    Chainsaw Brmmm Brmmm

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    That looks like a hell of a lot of work.

    I think around about post 30 I would have seriously considered a two pot paint and then polish option. But it looks ok, and who really cares?!

    It probably weighs less now and will go faster...

    DISQUALIFIED! :cool:
     
  18. bjmoose

    bjmoose Member

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    Re: helluva lot of work. -- yes it was. I don't recommend it. There's no rational reason to do that much work on a boat this old. From every rational perspective I should just have bought a new boat.

    Re: paint. I was far enough into the job there was no way I was taking on the additional work of a two part roll-and-tip job. I've already got way more into this boat than it's worth. And who could possibly sell you a paint with that funky 70's orange anyway? We used to have a car that color back in '73. But I digress....

    Re: it weighs less and will go faster...

    From the Laser rules:

    11. HULL FINISH
    (a) Waxing, polishing and fine wet and dry sanding
    of the hull is permitted, provided the intention and
    effect is to polish the hull only. Polishing/sanding
    shall not be used to remove mould imperfections.


    (b) Sanding and refinishing of the hull with the
    intention or effect to lighten the hull or improve the

    performance, finish, materials or shape beyond the original is not permitted.

    My intent was clear, and the photos demonstrate it. I suppose you could argue the effect. But my sander collects a lot of the dust (I won't say all of it) into a bag. There's no way that what I emptied out of that bag even added up to a full pound. Now there's no way to measure what blew away. But if I caught even 30% of the dust, then I didn't remove two full pounds of gelcoat, not to mention the bondo I put on to fix those trailer-induced dents.​

    The boat looked like crap, and I wanted it to look good. I fixed the appearance, though not as well as I would have liked.​

    I sail with old, heavy, varnished, wooden blades because I think they look cool and show the history of the boat. I like sailing a '75 laser because it was built roughly around the year I learned to sail. (By that logic, I should sail a '72/73 but they're even harder to find. The only older boat I saw for sale this year was in even worse shape than this one...)​

    I digress. But the point is that my conscience as a corinthian sailor is 100% clean. ​

    I race the SF Bay and my hull number is 25090, though I usually fly an old sail with a three-digit number on it for most events. If you race against me, feel free to protest me. We can follow all the procedures in Part II Rule 2, including measuring and weighing my boat, and the boats of 10 competitors. ​

    But wouldn't it be a better use of both of our time to hoist an adult-beverage and talk about laser sailing?​
     
  19. Bungo Pete

    Bungo Pete Member

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    Thanks for posting all of the pics and providing the info. It was a lot of work and I congratulate you for your diligence.

    A friend and I will be working on a 1990 boat this spring, and we will be going the clean/compound/teflon wax route.

    I will say that if I owned a boat with this type of cosmetic problems, (and in some ways, my 1979 is) I would've sanded, filled w/ fairing compound and then taken it to a boatyard that does painting. For a few bucks, you might be able to get someone to spray it as a piggyback job with whatever 2-part they happen to have in the gun (the vast majority being white or navy blue). The major cost of any paintwork is the preparation and you were almost 90% there.

    In any case, you have the satisfaction of having done it yourself and it certainly looks better than it did before. Good Luck!
     

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