Crack repair on PU fiberglass board

[armantas]

Hi all,

I was wondering what is the best way to repair cracks on a PU fiberglass board to ensure the board stays watertight. I have some cracks on my board that are still watertight but I am worried that at some point they may start leaking. I have attached a photo (sorry for the lack of focus, I can retake the photo if needed).

- Is it best to sand the cracked area and then apply SunCure?
- What about sanding to roughen, then placing a piece of fiberglass cloth and applying resin on that? Wouldn't a fiberglass repair be better/stronger?
- Leaving as is if the crack is still watertight?

I have several cracks like this (mostly smaller) on my board, all seem watertight (board is white under).

Thanks!

[waikikikichan]

- Is it best to sand the cracked area and then apply SunCure? Would work if the sand down area is deep enough. but is it worth opening up all those tiny areas ? ( probably going to leave a bump )

- What about sanding to roughen, then placing a piece of fiberglass cloth and applying resin on that? Wouldn't a fiberglass repair be better/stronger? Solarez and Suncure already has chopped fiberglass strands in the resin. If you are going to do the cloth method, have you laminated fiberglass cloth before ? ( probably going to leave a bump )

- Leaving as is if the crack is still watertight? If you run your finger nail over the cracks and it "catches", it will leak.
You can brush a thin layer of resin over the cracks just to seal it up. ( will leave a thin bump )

-I have several cracks like this (mostly smaller) on my board, all seem watertight (board is white under). How long have you owned the board ? Has those smaller cracks stayed white for the last 6 months ?

[armantas]

Thanks waikikikichan, this is very helpful. I have inserted my replies below.

- Is it best to sand the cracked area and then apply SunCure? Would work if the sand down area is deep enough. but is it worth opening up all those tiny areas ? ( probably going to leave a bump )

I see. OK, I will leave the cracks that are still white under and keep an eye on them for the next months.

- What about sanding to roughen, then placing a piece of fiberglass cloth and applying resin on that? Wouldn't a fiberglass repair be better/stronger? Solarez and Suncure already has chopped fiberglass strands in the resin. If you are going to do the cloth method, have you laminated fiberglass cloth before ? ( probably going to leave a bump )

I have not laminated fiberglass cloth before. I have watched many YouTube videos on how to do it, but have only used fiberglass cloth 1x time when filling up a bigger ding (photo below). In that case I have placed the fiberglass on top of PU, and then poured the resin over.

- Leaving as is if the crack is still watertight? If you run your finger nail over the cracks and it "catches", it will leak.
You can brush a thin layer of resin over the cracks just to seal it up. ( will leave a thin bump )

I see. When you say a thin layer of resin, I will assume you mean SunCure, let me know if I did not get this right, thanks!

-I have several cracks like this (mostly smaller) on my board, all seem watertight (board is white under). How long have you owned the board ? Has those smaller cracks stayed white for the last 6 months ?

I just got this board so I can't tell regarding discoloration, but I will keep an eye. I have dried the board for ~2 weeks so I figured now it's a good time to seal the cracks where the board under shows anything else other than white.

As a follow up question:
The board had an area on the rail where the glass was not hard due to a PU ding inside, so I peeled of the loose fiberglass and filled with resin over, see attached photo.

- Is it absolutely necessary to resin a fiberglass cloth over, or can I just leave as is? I think it looks better as it is now, i.e. without the fiberglass cloth, and seems structurally sound (other than needing some SunCure over the cracks), but I am not 100% sure.

The board in that area seems hard for the most part, there are a few quite small areas where the PU under is slightly detached, but not much. However, I did not want to peel off even more fiberglass unless really needed. Comments appreciated!

Thanks!

[waikikikichan]

I asked you many questions to make you think. Cracks and Shatters are inevitable. But to me they are worse than dings. Most board repair shops will fix dings but not shatters, they are not worth fixing. The benefits don't outweigh the cost and effort.

The cracks seem water tight but will they be in 6 months ? If they turn yellow, than it's too late. Moisture has got in which will turn to vapor and heat up and expand the blank causing the PU blank to De-Laminate from the fiberglass. Sea water is salt, salt corrodes.

So what to do ? Nothing, go surf. If there's no danger of being cut by fiberglass, than leave it, ride it till it dies. Then go buy another board. That's the nature of the beast if you ride PU/Poly boards. I can see already the deck is compressed and the fiberglass job is not prime quality. Probably your board is China made ( looks like a M.Dolsey ? ) I don't like shatters, that's why I ride molded-epoxy boards.

[waikikikichan]

- Leaving as is if the crack is still watertight? If you run your finger nail over the cracks and it "catches", it will leak.
You can brush a thin layer of resin over the cracks just to seal it up. ( will leave a thin bump )

I see. When you say a thin layer of resin, I will assume you mean SunCure, let me know if I did not get this right, thanks!

No, just resin ( and catalyst ) you brush on. Although you can find sun curing resin without the chopped fiberglass.

[armantas]

I see. When you say a thin layer of resin, I will assume you mean SunCure, let me know if I did not get this right, thanks!

No, just resin ( and catalyst ) you brush on. Although you can find sun curing resin without the chopped fiberglass.

Oh, I see, thanks!

- What is the rationale behind using resin + hardener without the chopped fiberglass? Will it stick better? More transparent color so I can see under?

[waikikikichan]

Ummm, I think it's best I step to the side for now and let you learn from trial and error.

If you want to learn from Youtube, I found the series from Fiberglass Hawaii to be the best.

Pay attention to the part on Hot Coat at 7:37