Hot coat sanding, fiberglass exposed.

General Discussion
1

Hi,
I was sanding hotcoat and at some parts i sanded the hotcoat too much that i could see the fiberglass. Is it ok or the water will sip in? Thanks
Milan

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2

Depends on whether or not you are putting a final finish coat on or not.

3

Gloss coat that thang and you’ll be good. Just dont sand through the Gloss coat haha.

4

Ya get some more resin on there. If it’s all over, make sure it’s sanded all flush and give it a whole new coat but lay it on pretty thin. Then you can start sanding with 320

5

Thanks Guys, I will try and put more resin on the parts where the fiber is showing. The board is 5’7" so I guess gloss coat will make it heavier?

6

At 5’7", the amount of resin you’d use for a gloss coat won’t even add a pound. I marvel at the way people obsess over a few ounces of weight, when most can’t even tell the difference in the way a board rides. If you are paranoid about weight, touch up the exposed spots, sand lightly, and do a spray finish.

7

Hi SammyA,
This is my first board so I am not sure about how much gloss coat really adds on. I read in Greenlights that gloss coat is not recommended for shortboard as it adds on weight. I am not sure if I should start a new thread for a few questions that I have but they are below. I would appreciate if you could advise me. Thanks.

  1. How thick should hot coat be?
  2. How thick should gloss coat be?
  3. What weight is considered heavy for a board with respect to it’s length? The board I built feels very heavy for it’s size. Used a 4+4/4 glassing.
8

A sanded gloss board is going to hold up better. A sealer coat of acrylic makes it even better.

9

A hot coat is also called a sanding coat, or filler coat. Done properly, there shouldn’t be much of it left after you sand the board.
Generally speaking, any coat of resin should be as thin as possible.
Most beginner glassers make the mistake of loading too much resin onto a board.

10

Also, if the board already feels heavy, what are you using as a comparison? Do you mean it feels heavy compared to another board of similar size? Or, does it seem like you added a lot of weght to the blank? A 4/4 + 4 glass job is pretty light, if done right.

11

I never get good results when I just spot-coat exposed weave and try to sand it down. I always just expose more weave in other places. I call it “chasing weave”. So in your situation I’d say you have 2 choices:

  1. Do another “gloss coat” over the whole board as some are suggesting. (Gloss resin if it’s poly; epoxy resin if it’s epoxy. You can use about 30% less resin for this final coat versus your initial “hot” or “filler” coat. IE, if you used 9oz for your hot coat, use 6 oz for your gloss coat.

  2. To save weight, just touch up the weave with some matte-finish Rustoleum 2x rattle can clear. That will make the white-weave become clear and seal it. When it is dry buff the Rusto. with some maroon scotch brite. THEN do 2 coats of Behr Acrylic Sealer (low-luster) wiped on with a sponge. Finally buff out that acrylic sealer with your maroon scotch brite, then grey scotch brite if you are feeling saucy. The maroon=320 grit equivalent and the gray=400-600 ish.

12

I am comparing with my 5’11" CI biscuit. I haven’t weigh it but it feels heavier.

13

Hi Jamie,
Option 2 sounds better. Why do i have to use acrylic sealer after using clear matte finish? Can I do away with just clear matte finish or just acrylic sealer? I have never used them before so I don’t really know how they work. Thanks.

14

Milan, I only use the Rustoleum 2x to spot-seal the exposed weave. It turns the ugly white weave clear. I use the acrylic sealer (get it at home depot) to coat the ENTIRE BOARD so I have a uniform clean final surface. Do a search on here regarding the use of the Behr Sealer. It is the “secret sauce” of many pro glass shops, so they say…

15

When you exsposed weave there is always a chance those exsposed areas may seep water if not properly sealed. When you see a board with lots of brown spots on it after a year or so; that is the reason.

16

What I use.

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17

Hi Jamie,
Thanks for the advise. I finally managed to find the Rustoleum and used it on my board, amazing stuff. I was unable to find the Behr acrylic sealer. I am living in Singapore and I read that Behr products are only sold by Home depot in US.

18

Yes, Behr is a Home Depot exclusive Brand. Not sure what equivalent there is in Singapore. It is an acrylic sealer for concrete and pavers. Milky white liquid, drys clear. I’m sure you can find something similar.

19

interesting i have never heard to spot seal with the rustoleum first. I have found the behr covers up and makes the weave go clear, but have also noticed that after a few sessions you start to see the weave again as the behr seams to come off pretty fast. Does the rustoleum spot coat prevent this?

20

In my experience the Behr will seal (it is after all, a sealer) but it’s so thin that it won’t fill any weave. The Rustoleum “2X” is pretty thick so it does a better job filling the weave than the Behr. Not as good as another gloss coat, but it definitely makes the weave clear and fills it if it’s minor burn-through. I am still waiting for someone to come up with a miracle sealer that seals and fills exposed weave. More viscous than the Behr but less viscous than gloss resin. A small fortune could be made on this. Emphasis on the word “small”.