Clive's iSonic 101 delaminated completely on the bottom, so we made a small incision along the rails almost the full length of the board, lifted the lid and filled it with a litre of resin. Sandbagged it, filled the seams with Epifill and sanded it down. Two coats of flowcoat and its good as new - but the proof of the pudding is in sailing it. Cross your fingers, boys an girls...
Looks good. I tried this once but it failed again a few months later. You might have better luck than me.
Did you perhaps weigh the board before starting the repair?
The weight comparison of before and after would be interesting.
I always worry about the seams cracking open during use, all boards flex a little while being ridden.
I've got 3 older boards waiting for that same repair if possible, but haven't touched them yet because I'm still not sure if it's possible.
With that in mind, I've been following this thread~
www.seabreeze.com.au/forums/Windsurfing/Wave-sailing/Whats-Mike-up-to-now/
I agree I have seen some boards injected with epoxy and they start absorbing water through the holes, you need to add a layer or fiberglass on top of the cuts to be safe
No fibreglass over the joints? I would expect the joints to open.
Let us know how it goes.
Select to expand quoteNotWal said...
No fibreglass over the joints? I would expect the joints to open.
Let us know how it goes.
Yer agree should be faired then glassed
Not just joints opening and letting in water. One of those joins is just in front of the fin box, this is possibly the most stressed area on a board, especially in chop or waves.
There's every chance the tail of the board will separate from the rest of it!
Select to expand quoteMastbender said..
>>>>>> but haven't touched them yet because I'm still not sure if it's possible.
With that in mind, I've been following this thread~
www.seabreeze.com.au/forums/Windsurfing/Wave-sailing/Whats-Mike-up-to-now/
I can almost guarantee this will be successful, not only because rider knows what he's doing, but because I've used a very similar method successfully.
If anyone has a knackered starboard around 80-85 cm wide please call me , Col 0416163807
Nope, we left the back attached so no cut in front of the fin box. Weight shouldn't be an issue as a litre of resin dried will weigh a little less thank kilo. Remember this is a slalom board not a speed machine. As for resin, the Epifill is made to be structurally strong enough, the cuts are not on the edges and should be just fine. The overriding brief was to keep the shape the same as the original.
All those negative comments and not one that said what a good job we did - thanks.
Select to expand quotezeeber said..
Nope, we left the back attached so no cut in front of the fin box. Weight shouldn't be an issue as a litre of resin dried will weigh a little less thank kilo. Remember this is a slalom board not a speed machine. As for resin, the Epifill is made to be structurally strong enough, the cuts are not on the edges and should be just fine. The overriding brief was to keep the shape the same as the original.
All those negative comments and not one that said what a good job we did - thanks.
I guess we didn't know that you wanted a pat on your head for what you did. They're not negative comments just opinions that don't agree with yours. Let us know how it goes and how long it lasts for. Great job 
as far as I'm concerned there was no sacarsm, just humor, as you might have noticed that red thumbs have been disabled recently on the forum
And I actually green thumbed your post cause I enjoyed reading it, was confronted to the same issue with my rrd firerace but gave up and binned it.
so good on you, and great job ! 
You've certainly done a good job, but to protect your investment you could fiberglass on top of the joints. I am surprised that instead of thanking the community for their precious knowledge and friendly advice you have taken it as a negative judgement.
Great work Zeeber. I've repaired some boards and learnt that the rails are key to strenghth, so good that they are intact. I do recall that when sailing the deck and bottom will be in both compression and tension at different times. So some glass over the cut across the board would be a good idea. It would add some more weight albeit small if care was taken.
Did you say EPIFILL....my best friend ..this stuff is as strong as glue ..and hard as a nut ..good job..there life in the old girl yet, 
Select to expand quotezeeber said..
Sarcasm is the weapon of choice of a weak mind...
Umm, nobody said anything personal, until this post, just saying.
Select to expand quotezeeber said..
All those negative comments and not one that said what a good job we did - thanks.
This looks like sarcasm, as in the "thanks" bit 
Well you get green thumbs from me for acting to repair that board. I have a bad case of procrastination when it comes to doing that stuff.
I am big on "sandbagging" my boards, though only the ocean can hear me saying " you stupid board why don't you go faster, you can't even go upwind, why don't you have footstraps in the right places, your to skinny and you aren't even this years colours"
whats causing this delamination? I really abuse some of my boards with lots of repairs but never experienced this. Noticed this issue being mentioned more and more.
Zeeber, you repair was experimental for you as per your fingers crossed quote. Best way to learn is by trial & error, so your on a good approach. If this repair fails, you have a least the answers as to why it may have failed, which shortens your future trial & error period for the next repair (if required). So a possible future result if you think about it.
Select to expand quotepeguin said..
whats causing this delamination? I really abuse some of my boards with lots of repairs but never experienced this. Noticed this issue being mentioned more and more.
>>>
Many cause for delam.
Failure to undo bung when the board gets hot or under low pressure in a plane's cargo hold is a good way.
Fatigue of the foam by heavy jump landings or lots of high speed chop work, especially with heavier sailors.
This last one is helped by a soft bottom layup, (not enough glass or carbon).
You can see in the first pic above where the foam is heavily stuck to the bottom, this is foam fatigue and it's separated a few mms below the surface. Once this happens it only needs a bit of air to get in that gap between the separated foam, then the next time you go sailing, the pressure on the bottom will force that air outwards, lifting the sandwich off the foam even more. The worse it gets, the worse it gets.
I'm not sure if there is any difference in foam quality, some may be more prone to fatigue than others, after all it's just a whole pile of been bag balls heated up so they stick together. If it's not a good stick, delam is going to happen more easily.
Yes but in addition I can see a LOT of styro that simply has not stuck to the divinycell
Insufficient resin.
You can see a big cross shape where it has adhered well, I wonder if they poured resin straight down the centre, then across the board in two places, and squeegeed it out from there. Then more was squeegeed out to the right in the pic and of course the straight lines where they poured have more resin. Certainly the best adhesion is close to one of those crosses.
Cobra shoddiness has as much to do with it as anything else.
All to save 50c of resin and 100g of weight at most. 
Mark, If it was a board I'd made those crosses would be center line marks, because they are a bit depressed, the resin has a better grip, I think that's why there's more foam adhesion there, not more resin, a pour couldn't possibly be that narrow. I think the adhesion to the foam although not brilliant is probably adequate.
The Delam started under the footstraps where most of the foam is stuck to the sandwich, and spread from there. More resin would only have slowed this process a little bit. What's needed is a stiffer sandwich that doesn't flex as much. Thicker d-cell or more carbon.
Actually yeah, looking at it that way I do think they are more like marking out lines 
But really, I dunno about the rest. Every mass produced board I ever repaired with major damage has an area that is clearly not wet-out right.......... and it just happens to be just where the crap started
Select to expand quoteMark _australia said..
Actually yeah, looking at it that way I do think they are more like marking out lines
But really, I dunno about the rest. Every mass produced board I ever repaired with major damage has an area that is clearly not wet-out right.......... and it just happens to be just where the crap started
I haven't had to pull the bottom off one of my boards, so don't know how it would look. But I've gone over to the wet the cloth out on the bench method. It certainly uses a lot less resin than wetting it out on the board, but that's the resin that would have soaked into the foam. The first few I did I was concerned that there wouldn't be enough adhesion, but so far it hasn't been a problem, and I've done a lot of km on them.
I suspect this is the method the factories use, so the cloth is well wet out but there's not much surplus to soak into the foam. Vacuuming the sandwich on squeezes a fair bit of resin out of the cloth on to the foam and d-cell though.
As mentioned earlier in this thread I'm doing delam repair but its a bit different as I'm re changing the bottom shape. Other times I've ripped the bottom of as in the way the guy did it in this thread painted on 100ml of resin mixed with some qcell and vacuumed it back on. Then around the cut on either side I've routed about 2cm wide down to the underneath glass put in a layer of 4 oz glass. On top of the glass replaced the routed out PVC with a new 2cm wide PVC then 2 layers of 4 oz over this. Sometimes the bottom I have vac bagged in has sunk a bit which I think is due to the foam getting damaged when the board had been used in a delam state.
Everyday we have a minimum and maximum temperature in a 24 hour period. If the vent plug is closed the board will expand and shrink daily, this stresses the weak bond between the beads 365 times a year. I also agree that softer laminates also cause the board to flex more and some bottom shapes slap more which stresses the board. The only time I close my vent plugs is when I go sailing on, I open them up again when I've finished.
Most Cobra factory delams I've see started 1 to 2cm inside the EPS foam. Yeah I've also seen some very dry super thin glass inside the board's
