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Ding Repair - How much fibreglass to remove

PostPosted: Wed Sep 10, 2025 12:05 pm
by rodr0drod
Hello all,

Got a ding in my board. I'm keen to repair myself and have a decent kit with everything I believe I need to mend it properly.

My question is how much of the fibreglass do I need to remove? I'm loath to dig away more than necessary.
It's a 2-3cm dia dent where something has knocked it and it's certainly cracked through the glass. I have removed any loose glass flakes but am concerned if I just repair over what is left the crack could spread or there could be some delamination under the dent.

Are my fears unfounded or do I need to cut away the lot?

Thanks for any advice in advance

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Re: Ding Repair - How much fibreglass to remove

PostPosted: Thu Sep 18, 2025 8:50 pm
by waikikikichan
#1 How are you going to fill the void ?

#2 How many layers of fiberglass do you intend to laminate over the crack ?

Re: Ding Repair - How much fibreglass to remove

PostPosted: Thu Sep 18, 2025 10:56 pm
by oldmansurfer
I would remove the dented part. The idea is to remove all of the glass that separated from the foam. If you leave glass that is not adhered to the foam then it may create a delamination that will grow. Maybe you are at that stage where you have little skill with fiberglass and resin so you don't want to do more than necessary. I used to be like that but now I am more worried that I won't do enough to make a solid fix. Perhaps putting more glass over the top of it will stop pressure on the delaminated glass keeping it from growing not sure of that.. There are many ways to fill in the missing foam. I used to save some foam granules from sanding foam to mix with resin and put in the hole, They sell a product to mix with resin Qcell and put in the hole or an easy one is epoxy putty.

Re: Ding Repair - How much fibreglass to remove

PostPosted: Fri Sep 19, 2025 5:09 am
by Geezer
If you want to learn how to do a fiberglass repair for the sake of further immersing yourself into your hobby, to become better acquainted with boards and board construction I can appreciate that. If it’s a financial thing or out of convenience and you don’t want to go to the shop for professional repair I have another suggestion.

If I’m concerned about how the board is going to look. I’ll take it to the shop for small little dings like this. What I do if I don’t care about having a white patch spot on the board is to use a two-part Epoxy marine grade paste. It has a five minute working time in paste state and then hardens to fully cured in like 12 hours. I slather the paste all over the crack, push into the hole and wipe the excess away gently until smooth with a wet cloth. After that it is sandable if you really want to have a super smooth finish….and it seems like it holds up forever. I keep some in the car and at home; I’ve done a parking lot repair and surfed on it 10min later and it held up. I’ve only done this kind of repair on PU boards I think; I had a longboard maybe 10years ago I might have done that was tuflite but I can’t remember clearly. I do know that all the repairs I have ever done with it there haven’t been any issues PM me for more info.

Re: Ding Repair - How much fibreglass to remove

PostPosted: Tue Sep 23, 2025 9:10 am
by rodr0drod
Thanks for the responses everyone. I actually went at it before I got any replies. Swell was on its way and I wanted my board back!

Like oldmansurfer said I was nervous about removing more than necessary but I wanted a proper fix. Wasn't to bothered how it would look. I ended up picking away more of the glass exposing a bit of the foam. Filled with Qcell and resin then a couple layers of fibreglass. Smoothed out pretty nice. Also found a small crack in the tail which I got a layer of glass over.

Things I learnt:
- There was a little air bubble in the filler which I thought would just be on the surface, when sanding it back I found it went practically down to the foam. I ended up opening this up and filling some more.
- Remove as much resin as possible when glassing. I was sanding by hand and gave myself a lot of extra work.
- Make sure you got all the grades of sand paper if you want the hot coat to come up nice.

So it looks pretty sorted to me, the blacks on the board look a bit duller where they have been sanded even at 1200 grit but I don't really want to spend anymore on polishing gear, maybe next time. Took me too long but I enjoy getting hands on. Can only get better at it from here, that goes for my surfing too!

Thanks again for the advice.