Hacking Gorilla Glue to make it foam *more*?

[CapnK]

Gorilla Glue is some neat stuff, I've been playing with it to determine whether/where/how to use it onboard, especially with regard to gluing foam.

Last night, I was trying to induce it into foaming even more than it does, with an eye towards using it as a bonding foam in the small gaps between foam boards I adhere to the hull for insulation.

As I understand it, water contact with GG creates a chemical reaction that causes the PU to outgas CO2, and it is this reaction that causes the foaming.

So, to a small amount of GG in a bottle cap, I added water, and stirred a lot. The glue took up approx an equal volume of water to glue, and, instead of the normal 3-4x expansion from the glue, I did get probably 20x the volume of the original glue amount as a nice, uniform foam. First experiment: Success. ;)

I also noted that the foaming happened three times: after the GG finished its initial foaming, I stirred the resultant foam, knocking it back down to its initial volume in the process, but it foamed right back up in a matter of a couple minutes. I then repeated the process to verify it a few minutes later. 3 times I defoamed the GG, and it foamed back all three times, over the course of about 30-40 minutes - which is much longer than the usual pot life of GG, from what I've read.

I've been Googling for a method to make the stuff foam as much as possible with surprisingly little luck. I would have thought someone had played with these characteristics of GG already. But No, apparently, I am out on the edge in my efforts, maybe even being the first person ever to try and hack Gorilla Glue.  ;D

I'm wondering - have any of y'all had an accident or experiment of some sort that made Gorilla Glue foam way more than the usual 3-4x its original volume?

My next experiment today will be to repeat the above 'experiment', and then try adding more water after the GG foams up initially, to see if I can get more than the approx 20x increase in volume that I've already achieved.

[AdriftAtSea]

While you're testing, you should probably also check to see how diluting the gorilla glue with water has affected its adhesion and tensile strengths.  If these are too negatively affected by the dilution, it doesn't make much sense to continue with experimenting, after all you do want to use it as an adhesive for the foam insulation first and foremost.

[CharlieJ]

interesting, but do be aware that the foam is brittle and has zero strength. The strength of Gorilla glue comes from the compression in the joint. Might work as a space filler though, as you are attempting.

[CapnK]

Yep - where I am using it, it will just be a foam insulator that happens to be just sticky enough to bond itself to the materials around where it is put. The foam boards will have been bonded into place already. So - No strength in this use is needed, it will just be easy, cheaper, and quicker to use the same material I have handy for bonding as a down-n-dirty insulating gap filler, too. :)

[Tim]

CapnK,
Although I have no direct experience, I have been told that Gorilla glue can seem tasty to dogs with deadly results. Just a heads up in case you leave any around in an open container.  :)
Tim

[CapnK]

Thanks, Tim! I read that last night, and found out why... I'd figured it would be a toxicity issue or similar, but it's not.

If a dog (or child, or whatever...) eats it, the GG goes into the stomach and does its foaming up and solidifying there. Not good!

Several people had posted experiences like that at a few places I saw. So - the GG is secured from CrewDog access. :)

[bayracer]

Anytime you create more foam, you are really enducing more air which reduces the adhesion properties, While the properties of foaming does help make up for some misfits or voids, trying to substitute or make up for this and stretching the raw material is not to your advantage if you are indeed going to depend on your glueup.

[Cmdr Pete]

First horses had to die to make glue

Now Gorillas?!?!?!?! >:( :o ??? :'(

There are more socially responsible alternatives

[CapnK]

Thanks for the input! I think I need to express what I am doing in a better way: :)

I'm bonding foam sheets to the hull, but not with the extra-foamy GG. For the important part of bonding foam to the hull, I am using the GG per instructions, mostly --> Obviously, I cannot clamp to the hull. :) I can brace, if/when needed, but have found a way to get good uniform adhesion that is stronger than the foam in sheer without it, so bracing isn't really necessary.

Once I'm done placing the foam sheets, which are cut 'not-so-super-accurately' (but quickly! ;D), I will use the foamy GG in the areas between foam sheet edges where my cuts are imperfect, and small linear gaps occur.

All that is needed regarding adhesive properties is for the foamy GG to hold itself into place until I get the ply/glass skin on over it - think "gap-filling spackle". The foam boards will not rely on it in any way for their own holding abilities, nor will it need to bear any load or have any other need for strength. The foamy GG will just be sticky filler.

By using my adhesive as 'spackling' as well, this way I don't have to buy another product, or have separate cleanup materials for it, etc... KISS. :)

I was just wondering if anyone had any kind of a 'happy accident' that resulted in GG foaming like mad, or was my best-yet experiment result probably near the limit of what I can expect from using the material in a way not discussed in the product literature... ;)

And - LOL, C'Pete! Good one!!! Grog fer the laugh! ;D

[Zen]

elmers  ;D

[bayracer]

I may have missed it with these tired eyes. What type of foam board are you using? Have you also considered gluing furring strips to the hull and then install the board to them? I have actually had great success with using bondo and glue up the strips as a quick dry to the hull, if the hull is bare glass.

[CapnK]

Zen - Google Gorilla Glue sometime, and read some of the glue-war threads you can find, about Elmers and others vs Gorilla Glue. It almost makes the anchor debate look tame... ;D

Bayracer - I'm using pink/blue sheet foam - housing insulation foam board. I've considered furring strips, but think it more likely that I'll go with a straight foam-to-hull bond, 2" of foam (2 x 1" sheets). Over the foam, towards the inside of the boat, will go 1/4" Luan ply or 1/8" door skins, and that will be covered with a layer or two of glass (between 4-10 ozs.).

In turn, the interior cabinetry will be made of a sandwich constructed the same way (Like so: glass/thin ply/GG/foam board core/GG/thin ply/glass) that will get bonded to the inner skin with glass tabbing.

[CharlieJ]

Bayracer- this thread is really an offshoot of one on insulating the hull- here's the link to the other thread.

http://sailfar.net/forum/index.php?topic=1352.0

[bayracer]

The blue board is really cheesy to bond much to and I would strongly recommend that you create a mini grid system so that you can fasten your face luan to a structual part. SOme of the pink board also has a plastic coating that needs to be peeled off. I would think that if you are attempting to get the complete board bonded securely to the hull shape which changes along most hull sides, that you may end up with a squeek if this does not happen. You also have a semi self insulating area if you keep the foam off the hull sides, too. These are just my thoughts from afar and my opinion. Check out and see if the glue melts or distorts the board too. I personally have never tried it with that board.

[CharlieJ]

Kurt- if it were us doing that, we would use some to the non-expanding foam in the pressure cans. If foams nicely, but stops when it hits pressure. That's how we did our ice chest. One can shoud do it for you.

More than likely a lot better insulating quality than the expanded GG.

And I'd STILL rather see your cabinetry bonded directly to the hull, with the insulation running up to that. I have serious reservations of the strength of your ply/foam/ply adhered to something glued to foam.

The ply/foam/ply laminate in and of itself sounds great- It's just where it attaches to the hull that I have a problem.

[bayracer]

Bayracer- this thread is really an offshoot of one on insulating the hull- here's the link to the other thread.

http://sailfar.net/forum/index.php?topic=1352.0

Thanks, Please disreguard me, as I knowith where I am today. ;)

[CharlieJ]

Hey- kick in your 2 cents. You're just as apt to teach us something as we are you ;D

[Grime]

I'm just thinking out loud. What about liquid nail? Or better yet talk to an insulation company for their thoughts on the subject.

[Bill NH]

And I'd STILL rather see your cabinetry bonded directly to the hull, with the insulation running up to that. I have serious reservations of the strength of your ply/foam/ply adhered to something glued to foam.

The ply/foam/ply laminate in and of itself sounds great- It's just where it attaches to the hull that I have a problem.

I need to throw in with Charlie as far as bonding interior structure to a foam sandwich...  Even if the skin/glue/foam or foam/glue/hull bonds are good, the foam itself doesn't have much strength in tension.  I'd worry about a load on the attached piece that would torque the joint at the skin along the hull, flexing and possibly delaminating your sandwich along the hull ...

[CapnK]

Thanks to everyone who is throwing in their $0.02, it's fun and I like the input. :) I can understand the concern, CJ and Bill, much food for thought. Here's the layout:

The foam coring pieces at their largest will be approx 6' x 2', the fore-n-aft dimension being the larger number (6') if I don't use/insert any vertical members (firring strips or ribs).

Referring to the drawing below - These foam cores will extend, heading aft, from fore bulkhead to main, and main to after, and vertically from sole to underside of bunk, topside of bunk to longitudinal rib (factory made & installed 2"mahogany) that runs along the hull approx 10" below the deck, and from the top of that longitudinal rib to just below the hull/deck* join. The skin and foam will tie into the hull and ribs/bulkheads at all the edges with epoxy and glass.

I was thinking that generous fillets and wide tabbing where cabinetry edges met the skin would spread the stresses enough that it would hold just fine. Thinking about what y'all have brought up, and imagining the boat beating around in heavy seas, she's likely to get shock-loaded pretty heavily in a bad scenario. I can see where that might cause a failure. Although all the structure will be tied together with glass and would probably hold, maybe this is another place to play it safe and put in some extra for little 'cost'...

So, without pre-placing firring/ribs, how about this: Where needed, I could bore through the inner skin and foam down to the hull, every 4-6" along the line where the cabinetry met the skin, and make a solid piece of structure (a 3" circle of epoxied ply, solid glass plug, or similar) that is attached directly to the hull. These would stop compression, as well as directly hold the structure from being pulled out away from the hull.

And for some background: what I'm doing is making a very thick exterior skinned foam core hull, but by putting the foam core in after (40 yrs after :) ) the exterior skin has already been made. Since these boats are basically a monocoque structure, with all the extra cabinetry I am putting in, I am reinforcing the hull itself internally as well, even without the foam core sandwich aspect.

By keeping the inner skin 'floating' as much as possible on the 2" foam coring, I am hoping that should I ever strike something that is able to puncture the outer hull, if I get lucky it might be slowed (or not strike deep enough) that there's a chance that the inner skin will contain or vastly slow the ingress of water. Having ribs, if they aren't really needed, might spread the shock of such an impact in a way that would damage the inner skin. Then again, they might serve to contain the water even more, by virtue of creating smaller spaces. Is this a case of '6 of one, half dozen of another'?

Admittedly, allof it is conjectural and far-fetched, I understand that - but as I'll be doing it if for no other reason than for the insulative and flotation properties, I figure what the h ee double-l. ;)

------------------------------------------

Notes about the illustration:
Longitudinal ribs are red.
Bulkhead stations are blue.
Foam pieces are green.
and
My apologies to He (the Alberg) for butchering his fine, fine lines so. I do hope that His ghost does not visit me in the night for this travesty... ;D

* (Hull/deck join to be reinforced w/epoxy and glass - strengthening it, then capped in foam, filling it in from the underside, and then more glass to tie deck down to hull again. Liner will join the underside of the deck on the top layer of this construct.)