Gorilla glue for fin box install

I think the expanding foam is great if you have ripped a box out and can replace ripped out foam.
If you are putting a US fin box in my preference is high density foam with glass and carbon layers, then grind excess off and cap it with glass/carbon. This way you can run a 30cm plus fin no problem and will take a high speed turtle crash to do damage.
If you are inserting small side fin boxes then it could be handy.
Out of interest what are you doing and what is the board construction?

Just to clarify it is a foil box in a big block of divinycell.
Trying to decide if gorilla glue is ok for the buttering in or just use resin and micro ballons.

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col5555 said..
Just to clarify it is a foil box in a big block of divinycell.
Trying to decide if gorilla glue is ok for the buttering in or just use resin and micro ballons.

Even more stress on a foil box, I would think. The expense of this would dictate a proper install, IMO.

Slow set epoxy won't get too hot. Make sure you tie that foil box into the deck too.

I agree - do it right. People using foaming PU glues are usually using it to fill a foam void (from ripping the old one out). Use epoxy.

If doing it in WA this time of year a super slow hardener is a must

West 105 and their super slow 109 - be aware its 1:3 not 1:5 like all the other West stuff.
Mix with your q-cells, but addition of milled fibre with help a LOT with strength.
couple of layers of 4oz around the divinycell block too.
Grind it off after install then cap the bottom of the board with at least 2 x 4oz about half A4 paper size
Cap the deck as much as u can and as heavy as you can will really help.... think 5 or 6 layers of 4oz tapering out

Thanks all for your replys !
Will do it the traditional way with resin, q cells and milled fibre as Mark suggested.

The Americans love the foaming PU for box installs ?

^^ again that is popular in USA as you have that density of 2 part PU foams. We can only get about 2-3lb and its pricey.

Its an acceptable alternative to routing a big hole and setting a big block of divinycell / corecell etc into the board as its hard to find thick foam without buying a whole sheet (at around $1000)


However, for the Aussies, the same effect can be achieved by simply laminating off-cut strips of 5mm thick divinycell / corecell etc around the box and then setting the whole thing in the board (like a slot box is)
Especially if its just for small fins like a thruster conversion

So, is 8 lb pour foam the equivalent of using a divinycell block or just to fill up space?

Why do people still insist on using imperial measurements?
I blame the Seppo's. Why couldn't hey just move to metric like the rest of the planet did 50 years ago?

Why do some people wrap the box in glass before gluing into the foam ?
Isn't that just putting a layer of hardness around an already hard box . Whats the benefit ?

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forceten said..

Imax1 said..
Why do some people wrap the box in glass before gluing into the foam ?
Isn't that just putting a layer of hardness around an already hard box . Whats the benefit ?

The glass and or carbon, is a reinforcement, it adheres to the box and the material the box is going into, so chemically infused to both. If ever you remove a box that was installed in this manner it becomes apparent, by what comes out.
Foam you mention , hopefully is something more dense , unless it's pour foam, or cell .
the core on windsurf board is EPS, this needs some further strength, in my very humble opinion.

I understand what your saying but still don't get it
When I install boxes I rout out the correct size hole in the laminate then gouge out the eps a good inch wider and deeper than the box . Then fill with hard two part expand foam . Then re rout . Just as strong or stronger than a cell block because your leaving more of the original laminate . I use this method when adding boxes , repairing boxes , putting boxes in during a build and plug inserts. Waffling now .
I still don't understand what wrapping the box does .
Resin sticks the same to a box weather it's glassed or not and the same to the cell block ,the way I understand is wrapping the box just slightly makes it bigger . It's still going to fail the same where it joins to the cell. or am I missing something .?
I get it if the box is pushed into a glass lined hole and there is excess glass that gets feathered out sideways onto the foam or laminate.
Confused.

Just glass Col.
The reason I said cap the deck lots is to avoid the upwards 'push out' and its easier to refinish compared to blending out more than a couple of layers on the bottom.


Imax - I believe in wrapping the box with glass for a couple of reasons
Same as putting in a divinycell block, it spreads load more. The glass is much higher tensile strength that just the filler of resin an q-cells or whatever, so for one end of the box to try and sink by point loading the foam underneath becomes much harder.
Further the glass protrudes above the deck and is then ground off flat, and the deck laminate bonds to it. Again, the glass is stronger and will resist the box movement better than just a filler-to-deck-laminate bond will.

Well...ahhh, I disagree Gorge Sailer, and further do agree with Marks discussion.
if I'm installing boxes in a brand new board or a $50 swap meet one, I want to do the job once, and strong enough.
US box have no provision to "tie into the deck". They were designed for small fins , I use the same procedure with them as any other I install.
powerbox and tuttles are primarily used on long fins, so need even more structor support. I do recall Starboard used tuttles on wave boards, some years back. Notable are Mikes Labs, from the Bay Area in California, who used tuttles on near everything. My use of materials started with my first tri fin conversion, like 2006, yawn bored bla bla, I used the recommendations, do several builders, most notable Bouke of Witchcraft.
as I said before, more than one way to bake a cake.

the OP question was the use of Gorilla Glue, what is your opinion on that ?