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PostPosted: Wed May 30, 2012 7:22 pm 
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Location: Cape Coral FL
Long story about how the hole got there, it was a bummer as i just competed a bottom job, and she was looking better than ever. But, since i had all the supplies, it was back to the garage.

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After careful inspection, i determined that the hole did not go through the back side of foam nor the back side of the sandwich glass. So i figured that i had to fill the hole, then repair with glass, then gel coat.

here are the supplies used:
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So, with the hull on its side in my garage, i filled the hole with some polyester resin, making sure to get as much jammed in there as i could, not being concerned about being neat. This is very important to remember, and an important tip. In this entire repair it is about applying material and then removing the excess. At every step, apply then remove using 150 grit sandpaper.

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Notice that the resin is overflowing the hole, but it was about getting it in the hole that was important. After a couple of hours too dry i then sanded the excess.

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Notice how much larger the repair area has become. It gets a lot larger, this was also very important. While it is hard to make this small hole larger, I determined it was critical to ensure proper glass application. furthermore, to ensure proper gelcoat blend, i knew the area i was going to apply gelcoat to was going to be about the size of an 11x8 sheet of paper, so I did not let myself become scared of how much sanding i was doing.

What is also important to notice is that you can now see 3 layers of gelcoat, and this becomes critical later. You can see beyond the repair is clean and shiny gelcoat, then you can see the scuffed sanded "outer" layer, then you can see the "yellowish" under layer. For good gelcoat application it was important to pay attention to these three layers, as they tell you how good your "taper" is from good gel coat to the point of no gelcoat.

next i applied 4 layers of glass, another reason the hole needed to be larger was to ensure i stretched it to good fiber layers that were not damaged. After, sanded off the excess again.

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At this point, i may have removed a bit too much, but when i ran my fingers over it, the level seemed right, but i was planning on filling with Formula27 anyway, so i did not worry. Next, filling with Formula27 and of course, removing the excess

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At this point, when i ran my fingers over the repair, I could slightly tell it was there if you had your eyes closed. I now Know that the level of the repair is just even with the "taper" point of the last layer of "yellow" gelcoat. Also notice, just to the right of the sanded Formula27 you can barely see a sliver of the dark fiberglass, another indicator that the Formula 27 was even with the fiberglass, and not higher than the gel coat around it. This was all done in 1 day, now day 2 it was onto the gelcoat.

I used a 50/50 ratio of white gelcoat and the Duratec High gloss additive with NO additional thinners. The acetone was only for cleaning after sanding. As for the color match, i used only the mustard color that is in the picture. Matching the colors is surprisingly easy. What is surprising is how little mustard is needed to turn the bright white just a little off color. In the mixing cup, i would add the mustard with a tip of a toothpick, stir, and then hold a Popsicle stick dipped in the liquid up against the boat next to the repair. is starts out by being too white, but add a drop more, mix, and check again after about 5-10 repeat procedures, it starts to become very difficult to tell. At this point STOP. You are done when it IS difficult. This means you match. If you go further, you over color and it will look awful later. Much better to defer to the lighter side than the darker side.

Next, apply the gelcoat with the prevail sprayer, notice i removed the pinstripes now, and do not tape off the area at all. Over spray at this point is good, remember, add material, then remove the excess. When you start to sand down and remove the over spray, if you are careful, the repair area will be unnoticeable.

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What is hard to see in the picture above, is that the new gel coat looks like the front of the boat, it is just around the new spot you can see the over spray that is cloudy, this will all be removed in the sanding/buffing step.

Now i wet sanded with 1000 grit sand paper.

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Then used aqua buff 2000 (not pictured) to polish the entire area. If i had not just done a bottom job, i would have needed to buffed the entire side of the boat, as the repair area looks brand new at this point.

After buffing with new pinstripes:

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Done in two days, looking like it never happened.


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PostPosted: Fri Jun 01, 2012 8:19 pm 
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Location: Charlotte, NC
Thank you for this post coralreefer - great DIY resource. I'm on the tail end of repairs myself and while have read/watched videos a lot about fiberglass repairs wish you had posted a few weeks ago :) but so far so good. Ready to prep and gel coat.

Question is, my products are from a supply house so not in kit form (with pumps or set ways to measure quantities) and it looks like you have the same more or less.

Assume the area is not much bigger then yours x 3 plus we are hitting some cosmetic scratches we've widened out for the repair.

We may only need 2-3 oz of gel coat at a time... so how did you determine how much hardener to use for the gelcoat? I'm thinking 10-12 drops for that 2-3 oz of gel coat at 80-90 degrees?

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'85 H16 __/) 87468 Tidal Wave
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PostPosted: Sun Jun 03, 2012 9:01 am 
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Location: Cape Coral FL
Jon,

I kept it basic and stuck to a 2% hardener ratio. The other factor to consider was how accurate you can get with your measurements. The little cup in the picture went down as low as 2.5 cc/ml which is 2% of approx 120 cc/ml of liquid, which is equal to 4oz. So, i mixed 2oz of Gelcoat with 2oz of DuraTec and approx 2.5 oz of hardener.

This was more than enough, but all fit in the prevail bottle which is a 6oz capacity.

Hope this helps, good luck.


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PostPosted: Sun Jun 03, 2012 9:02 am 
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correction,

it should say 2.5 cc/ml of hardener for the 4oz mixture.

writing too fast.


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PostPosted: Sun Jun 03, 2012 11:34 am 
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Location: Charlotte, NC
Thanks again coralreefer - that's what we'll shoot for.

Edit: worked just great using your ratios. I had stepped on our cc cup but recalled reading 2.5 cc = about 1/2 teaspoon.

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