Fibers showing through gel coat?

moknots · Posted: Tue Oct 29, 2013 11:09 pm Post subject: Fibers showing through gel coat?

Recently bought a 1987 22' Angler. Blue gelcoat accents were badly oxidized, so with the help of a very experienced compound buffing dude, tackled it with medium followed by fine buffing compound. Here's before. You can barely see (or at least we could in real life) a bunch of white spots.

[img]http://www.c-brats.com/modules.php?set_albumName=Bloo-C&id=before_buffing&op=modload&name=gallery&file=index&include=view_photo.php[/img]

After buffing, it was YIKES. Whats with the white worms?

[/url]http://www.c-brats.com/modules.php?set_albumName=Bloo-C&id=after_buffing&op=modload&name=gallery&file=index&include=view_photo.php[/[url]

We absolutely did not overdo the buffing compound. Just enough to get out the fine scratches and oxidation. What on earth have I got? Cure?

I am thinking I have no choice but to paint over the gel coat with hull paint if I want it to look decent. Appreciate any info[/url]

Sea Wolf

Sunbeam · Posted: Wed Oct 30, 2013 12:04 am Post subject:

If you look closely at the first photo, you can see a pattern/texture of squares, sort of like large burlap. I would say that's the underlying fiberglass cloth showing through. Probably the same UV/sun that dulled the gelcoat contributed to a bit of "post curing" which brought out the texture of the fiberglass weave. That in turn could have made high spots, which you buffed through. Or, as Joe says, it might just have been thin there (originally, or after previous buffing). Or a combination of all three.

(Post curing, basically: Fiberglass resin doesn't ever really stop curing, it just continues to cure very very slowly over time. However, if it gets hot - like say a dark color in the sun - then it cures faster/more. Then the pattern can emerge (as you see in the first photo). It's one reason very dark colors (black) are not recommended - especially in hot climates.

When a customer wanted a dark colored boat one time, the yard built it, then subjected it to high heat to purposely "post cure" it. After that it was completely sanded and faired, and then painted the final dark color. That helped to avoid the problem, but no production boats are made that way.

So, as was mentioned, the way to "fix" it now is to paint the stripes. A top job, in my opinion is a two-part paint (really a "coating") either sprayed professionally, or rolled and tipped. This produces a very long lasting shine and a hard surface. A one part paint is somewhat cheaper and easier to work with, but also softer and the shine doesn't last as long (a good two-part can shine for 10-20 years depending on climate).

A bummer to have happen, but also an opportunity to have a uniquely colored (trim) C-Dory, to look on the bright side.

ghone · Posted: Wed Oct 30, 2013 10:58 am Post subject:

Joe and Sunbeam are correct. You didn't do anything bad. Gel coat isn't a forever finish. Someday we all must paint. The big deal is to really be sure to get all the previous waxes, silicones etc that owners have put on over the years prior to whatever paint system you use. Interlux has some nice DIY products as do others. I've seen a roll on finish look excellent. Roll on and tip off with a brush. Pretty easy. George

colobear · Posted: Wed Oct 30, 2013 11:44 am Post subject:

What does the term "tip" mean with regards to painting on the boat?

ghone · Posted: Wed Oct 30, 2013 12:09 pm Post subject:

Hi Barry Tip or Tip off is a technique for roll on paint finishes. You roll on the paint using a high quality foam roller usually and do a couple feet and then immediately "tip" with a high quality brush in the direction of flow to smooth any roller marks. Just a light touch needed. The brush helps level the finish. A high quality job can result and much less $ than a spray job. George

moknots · Posted: Wed Oct 30, 2013 12:10 pm Post subject:

Thanks! Seawolf, did you fix my photos? What'd I do wrong posting the pics?

wailedcentipede · Posted: Wed Oct 30, 2013 12:16 pm Post subject:

tip off with a brush ... fine rollers some times leave a fine mat like finish ... you very lightly follow with a brush and tip/feather out the mat .. if the paint is fast trying follow up right away ... in my puttering about the brush is in the paint just make sure theirs no excess paint on the brush, a dry brush may pull and cause steaks? (some paints flow out on their own) hope that's what your looking for ... wc George got ahead of me scratch this message ...lol..

bridma · Posted: Wed Oct 30, 2013 12:27 pm Post subject: Fibers showing through gel coat?

When I bought my boat there was some scratches both sides on the blue stripe. I tried a roller and 'tipping' with a brush. I just could not get the hang of it. So I painted both sides with the good quality brush I bought for 'tipping'. It came out just fine, I was really pleased with it. Might not be as good as a professional painter would do, but saved me a lot of money and was easy and quick to do.

Martin.

thataway · Posted: Wed Oct 30, 2013 4:23 pm Post subject:

The first photo shows some print thru of 18 oz woven roving. Often there is a thin layer of mat (3/4oz to 1.5 oz) laid down outside of the roving to avoid "print thru". Agree you cut thru the blue gel coat, and then hit some of the mat fibers. To get the best paint job, you should sand, put down a primer first and then lightly sand it again before doing the color stripe. For this size stripe you probably will do just as well doing it with a very high quality brush.

For roll and tip you need two people. For just one person using TopLac or BrightSide, you put the paint on in diagonal, then horizontal and finally tip it off with vertical strokes.

Sea Wolf · Posted: Wed Oct 30, 2013 5:03 pm Post subject:

AstoriaDave · Posted: Wed Oct 30, 2013 5:38 pm Post subject:

Moknots,

Maybe someone already mentioned this, if not: the roller nap should be thin, maybe eighth inch, esp. if the paint is thinned. Better paint stores will have them, or you can order from System Three. The usual heavy nap used with home latex paints is waaay too heavy. Hard to find these in narrower widths, so I buy 8 inch rollers and hacksaw them down to 4 inches on narrow jobs.

Thataway's sequence is perfect for roll and tipping. Most folks overbrush on the tipping. Another tip: sometimes a brush will fill with congealing paint. Helps to have a backup brush handy, clean, and barely freshened with whatever thinner the mfr recommends for the paint.

Two part paints require a little practice before committing to the job. I have had good success with System Three's WR LPU, but you really have to control the humidity to get a glossy shine. If you are working outside, impossible. I use it because it is water based, and kind to my lungs.