So I am at the gold coast having a lovely sail when the fin ripped the fin box out sideways managed to grab fin but lost it on the way in . So now i will have to wait till im in sydeny to get repaired . Thats the end of that. So how much to get repaired professionaly & how hard is it to repair myself ? Im so sad

If you've got some (unhappy) snaps it may be easier to assess and quote.

im guessing it's a power box and the post where the fin is screwed in has given away

I use this site to check out whats needed
boardlady.com/

Have a look at what she says while looking at your job.

Thanks ka43 I did go see surf fx they gave me a board repairs no so i went & saw him he said it would take a few days to repair as the epoxy needed more time to cure.I thought about buying a new board but i calculated that i couldnt afford the divorce.Ill get it fixed when i get home . Winds droped off anyway . Im looking on the bright side it could have happened when i was out in the ocean . I hit a rope about a month ago but it seemed rock solid . So was it me just overpowering it with a big fin or did i damage it & not notice & then it let go when i overpowered it. I dont want this to happen again thats for sure .

actiomax said...

I dont want this to happen again thats for sure .

That will depend on how well it's repaired.
I normally tie the box to the deck and the bottom of the board. You can't rely on soft styro foam to hold the box in place.

^^^ sounds like a stoopid idea. The bolt in powerboxes and tuttles is designed with too much clearance with the female threads in the fin so the bolt can rip out easily.
The box should be strong as blazes and there is no need to design a substandard box..

Keef I was saying making fragile boxes is the stupid idea because of the fact the bolt is designed to let go

actiomax said...

It looks to me as thought the box was only glassed were it joined the bottom deck & the rest of the cavity was just filled with expanding foam.

mark couldnt agree with you more
yes actionmax the box is lightly glassed and they run a strip of 5mmx10mm divinicell around the cavity for it to sit on and just resin the box in, then fill the cavity with expanding foam and then resin the post onto the box then glass the post to the deck,(well thats what it looks like to me ) the hole setup is a bit fragile and its a wonder there isnt more boxes rolling out

Basically for strongest repair....

Router it all out about 30cm x 10cm.
You won't be able to router it out to full depth or you will take some deck laminate out ( remember it is curved) and watch out for rear footstrap insert!!!

Then scalpel cut and dig dig until you have made that nice rectangular hole go all the way thru to the divinycell layer on the deck side. You want the next couple of steps to bond to the sides AND the deck.

Insert a block of divinycell (30x10cm ish) in the hole. Make sure it is profiled on the bottom (well the board is upside down so really it is the top ) so it matches the deck shape well. This is a long step with sanding the d'cell block to fit well.

Butter it with epoxy / q-cell mix and bung it in. Vibrate the jebus out of it to get rid of air bubbles and refill around edges as necessary (NO voids). Get the mix in anyway you can, popsticks, syringes, anything. Helps to have excess resin/q-cell mix in the bottom of the hole before you bung the block in.
Make sure it is a tiny bit proud of the board.
Weight it so it does not try to float.

After it is cured, sand back flush with board.

Router hole for new box.

Draw a line on wall (about 5m away) horizontally with a spirit level and then give it a right angle line with a t-square. Put board on saw horses and line up bottom of board with horizontal line. Tape board down to saw horses so it can't move at all

Cover fin and inside of new box with Kiwi shoe polish (good mould release) just in case you get messy.

Butter box with epoxy/q-cell mix
Layup with 2 layers wet glass, then butter again.
Insert into hole

Line up fin with the vertical line on the wall by eye , and then it is well and truly close enough to 90deg to board. Masking tape it in place (tip of fin to rail both sides. Lots of good gaffa helps)

After curing, set router to about 2mm depth and route out all the divinycell and the box.... that will account for thickness of the glass
Bevel edges of old glass

Glass over with 3 layers, when close to cured cut about box slot with scalpel (being sure not to lift the glass away from box). Let it cure, sand, fill, sand, paint.

sweet.

(it really helps with pics, but that is the gist of it)

decrepit said...

unless you stop the box twisting, the same thing will happen again!
The foam isn't strong enough to do this.
That broken black peg is what was doing the job before, and it obviously wasn't adequate. (I've had several finboxes go exactly the same way, the peg snaps and box rolls)
If you can get a continuous couple of layers of glass around the box and tied to the bottom that will help. Or a divinycell/carbon sandwich alongside the box going all the way through to the deck, and tied to the deck and bottom. then the damaged bottom area around the fin needs to be structurally continuous from the rails up to the fin box.

That's in my method
I agree. The main thing is the block that the box is inserted in needs to bond to the deck and the bottom glass and the plug needs to bond to the deck also.
I actually left out a step that helps it bond to the bottom glass even better but it is too hard to describe and it really is only necessary on the most abused of waveboards or things running 50cm fins with 130kg sailors

Mark, looks like this is a race to see who can out type who, but seems basically we agree with each other.

decrepit said...

You beat me Mark,
Only comment I have, is that the glass around the fin box, has to overlap onto the bottom for a couple of centimetres to stop box twisting, if there's no overlap onto the bottom you're still only relying on the d-cell strength, depending on the density, that may not be enough. and there's no point using fibreglass at all unless it does overlap onto the bottom.

Yeah I left that bit as it can be hard to describe.
After routing the fin box hole I then route about 50mm of d'cell out on the sides of the box about 1mm deep for the glass to sit in, and then also round the edges of the hole the box is going in so the glass can lay over more easily.
Picture worth a thousand words but the only pic I have of that was given to me by a board manufacturer so I will not post it here as he may not want to give away secrets

the box i repaired i made a new post useing a sparkplug socket as a plug and glassed it in with carbon roveings top and bottom

I'd go for 80kg/m3 d-cell.
I'm not sure carbon's essential, but it won't hurt to use it, 200gm/m2 is about right. 1/2m2 will probably do.

You shouldn't need much epoxy, 250mls should be stacks.
Qcell depends how good a job you do and how much bog you need, again 250mls should do you.

I'm still waiting for the fin box. I will post pics Keef .Thanks decrepit I wanted a shopping list to take To the glass suppliers. I hope the box comes soon as I'm still off work with sprained ankle & it would be a great time to do it. I have done a bit of fiber glassing over the years so i feel confidant enough to use carbon fibre. I think that the fin box repair is a step towards making my own board. Thanks to Mark as well without your excellent advice fellow windsurfers I probably still would have done it myself but an inferior job . I'm hanging to get it fixed I'm so frustrated limping around the house . I want the board ready for when I'm ready should be soon .