Started what I thought was a simple impact repair today, but when I removed the surface damage I found a lot more underneath. The strange thing is, the cracks in the d-cell, and the underneath cloth, look as though there's resin in them.
So no sign of damage on the surface on top of these cracks in the sandwich.
So was the board damaged during construction and the external glass just laid over the cracks?



So the white foam running vertically is where the damage went all the way through to the surface and had cracked all the way through the core foam.
The hidden damage is a right angles to this. If you push down near one of these cracks, where you are pushing moves independently to the rest.
I started following the cracks with the router, trying to set the router just above the underneath glass so I can bond new glass to it.
But the d-cell varies greatly in thickness so this makes it hard.

The whole deck area around this is depressed, but there is no sign of any delam.

Has anybody seen this hidden damage before?

Divinycell should of course all be same thickness, and cracks underneath hmm,makes me wonder if it was factory damage filled with resin and foaming additive like the dodgy buggers use normally around inserts /boxes/track??
Just a thought

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Mark _australia said..
Divinycell should of course all be same thickness, and cracks underneath hmm,makes me wonder if it was factory damage filled with resin and foaming additive like the dodgy buggers use normally around inserts /boxes/track??
Just a thought

Looks more like one layer of d-cell but quite thick at the thickest part, I'll have a closer inspection tomorrow, and see if it is actually an extra layer where it's thick.

Strange! maybe someone fell on or dropped blank and damaged it, then repaired it with expanding foam but left a bump then covered blank with PVC then sanded down PVC to get rid of bump then glassed.

this could be a lot of bull**** .

The resin seems to of had a reaction with the foam ..
perhaps eating the foam leaving gaps OF NO FOAM ,step on it and all is left is the outer surface
creating cracks .

that could only happen in the factory ...someone has used the wrong resin ,or more than likely made the batch too HOT.

JUST A THEORY.

but i have melted foam with resin .and it goes that ugly brown colour .

i like your router job.

Tardy, the ugly brown colour is the divinycell sandwich. The polystyrene foam underneath is fine, except where I've attacked with a knife to dig out the damaged stuff, under the surface crack.
The photo is a bit misleading, you don't get the 3d effect, at the thickest part the divinycell is about 5mm at it's thinnest around 3mm.
Mike, no sign of expanding foam, it's all large celled polystyrene.

I'm wondering if it could just be a failure of the sandwich in compression? It's between front and back straps, the current owner is a fairly big guy and the board is far from new. If the underneath glass gives way, then the sandwich can flex downwards without damaging the surface glass, but splitting the divinycell. Would the crack in the d-cell be a dark line in this case?

I smell a cover up, but literally a factory cover up, it does happen, they make them by the 100's, and sh1t happens.
Or maybe a simple surface dealm, the glass on top can flex quite a bit without cracking, no leaking, but each bump drives the foam deeper, as long as there is a foot there, was a foot there?

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Mastbender said..
I smell a cover up, but literally a factory cover up, it does happen, they make them by the 100's, and sh1t happens.
Or maybe a simple surface dealm, the glass on top can flex quite a bit without cracking, no leaking, but each bump drives the foam deeper, as long as there is a foot there, was a foot there?

No delam, good bond between all layers.
Definitely a foot there, right between front and back straps, so light wind dogging and gybes would have had back foot on the damage.
No sign of a previous repair.

I'm starting to suspect it's a failure of the inner sandwich, as you say the top layers of glass are flexible enough to allow quite a big downward movement without cracking. And there's definitely been a big downward movement. In the are of the damage the deck has probably sunk 3mm to 5mm. It could also be this that's making the router go through the underlying glass in some spots, but getting no where near it in others. The difference in d-cell thickness may not be anywhere near as great as I thought.

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Tardy said..
this could be a lot of bull**** .

The resin seems to of had a reaction with the foam ..
perhaps eating the foam leaving gaps OF NO FOAM ,step on it and all is left is the outer surface
creating cracks .

that could only happen in the factory ...someone has used the wrong resin ,or more than likely made the batch too HOT.

JUST A THEORY.

but i have melted foam with resin .and it goes that ugly brown colour .

i like your router job.

I think you would struggle to find the wrong resin in the Cobra factory - and can't mix epoxy to be too hot when it is laminating such thin layers (they wouldnot be using fast hardener)

I reckon Mike is onto it with damaged blank

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Mark _australia said..

Tardy said..
this could be a lot of bull**** .

The resin seems to of had a reaction with the foam ..
perhaps eating the foam leaving gaps OF NO FOAM ,step on it and all is left is the outer surface
creating cracks .

that could only happen in the factory ...someone has used the wrong resin ,or more than likely made the batch too HOT.

JUST A THEORY.

but i have melted foam with resin .and it goes that ugly brown colour .

i like your router job.

I think you would struggle to find the wrong resin in the Cobra factory - and can't mix epoxy to be too hot when it is laminating such thin layers (they wouldnot be using fast hardener)

I reckon Mike is onto it with damaged blank

Don't you believe it ,can't mention the board name but had some bad **** happen in 2013 -2014 .
in the cobra factory .

with resins .

not saying this is the problem here though...