glue vs epoxy

[aggie79]

I found an interesting comment in this quide to epoxying surfboards. At the bottom of page 10, in speaking about how to seal the EPS foam blanks, the author says that he doesn't remove the foam dust from sanding. He leaves it in place and adds a coat of epoxy. Apparently, the foam dust and epoxy mixture bonds better to the foam than an epoxy and micro balloon slurry.

http://www.foamez.com/pdfs/Epoxy%20EPS%20Construction%20Guide.pdf

[Larry C]

I found an interesting comment in this quide to epoxying surfboards. At the bottom of page 10, in speaking about how to seal the EPS foam blanks, the author says that he doesn't remove the foam dust from sanding. He leaves it in place and adds a coat of epoxy. Apparently, the foam dust and epoxy mixture bonds better to the foam than an epoxy and micro balloon slurry.

http://www.foamez.com/pdfs/Epoxy%20EPS%20Construction%20Guide.pdf

Thanks, Tom

That is a lot of great info about foam. It looks like pre-sealing is the norm before laminating. I am surprised about using spackle for sealing. I am going to test several of these methods.

[linuxmanxxx]

The dow blue and owens corning pink are both xps and according to this epoxy article will always under extreme heat release trapped gas and cause delamination bubbles when heated and cooled. It's gas trapped in it during manufacture as well as it releases polystyrene which nothing will stick to at all. Interesting article indeed and says the best is a EPS with a new method only made in florida and california on specific machines and no idea how the heck to find it and buy it. Has to do with which passes water instead of blocking it. The xps will not pass water but has the gas problem and old eps will pass water.

So in fact it is the foam that is the problem but again I think a flexible glue would make the problem less a possibility because the glue can stretch and flex back instead of just shearing off like a hard one would do.

Theories theories theories hmmmmmmmm

[Larry C]

The dow blue and owens corning pink are both xps and according to this epoxy article will always under extreme heat release trapped gas and cause delamination bubbles when heated and cooled. It's gas trapped in it during manufacture as well as it releases polystyrene which nothing will stick to at all. Interesting article indeed and says the best is a EPS with a new method only made in florida and california on specific machines and no idea how the heck to find it and buy it. Has to do with which passes water instead of blocking it. The xps will not pass water but has the gas problem and old eps will pass water.

So in fact it is the foam that is the problem but again I think a flexible glue would make the problem less a possibility because the glue can stretch and flex back instead of just shearing off like a hard one would do.

Theories theories theories hmmmmmmmm

Interesting stuff...

http://www.youtube.com/watch?v=5qSSchUSbyY

[GPW]

Interesting , but not necessarily TRUE ... ( you don’t really believe Everything you see on You Tube ) Foam (EPS) actually comes in a few colors , Blue, Green , Pink , even white ... The more common “beaded foam is usually white , but can be Blue also ... “ a rose by any other name “ ...
Expanded polystyrene , expanded Urethane , expanded poly propylene , many types of foam to choose from in many densities ... some even considered “structural “ for the more common home building practices ...
It’s amazing one can go on the net and post inaccurate information to suit their business opportunity, and people believe it , but it happens every day ... Might as well be a political ad ... we don’t believe ANY of those either ...

[Larry C]

The dow blue and owens corning pink are both xps and according to this epoxy article will always under extreme heat release trapped gas and cause delamination bubbles when heated and cooled. It's gas trapped in it during manufacture as well as it releases polystyrene which nothing will stick to at all. Interesting article indeed and says the best is a EPS with a new method only made in florida and california on specific machines and no idea how the heck to find it and buy it. Has to do with which passes water instead of blocking it. The xps will not pass water but has the gas problem and old eps will pass water.

So in fact it is the foam that is the problem but again I think a flexible glue would make the problem less a possibility because the glue can stretch and flex back instead of just shearing off like a hard one would do.

Theories theories theories hmmmmmmmm

Steve,
Wouldn't it stand to reason that any coating would suffer a similar fate of delamination from out-gassing? However, the epoxy/glass will not burst, just delaminate in a small area from the foam. the elastic coating could possibly burst, like latex paint on a house does from vapor pressure getting through walls. I think the answer is to find the right foam to use regardless of the coating method.

[GPW]

Or find the right coating regardless of the Foam ...

You know , we’re not building the Pyramids ... Just a humble camping trailer for we of the 99% ...

[Larry C]

Interesting , but not necessarily TRUE ... ( you don’t really believe Everything you see on You Tube ) Foam (EPS) actually comes in a few colors , Blue, Green , Pink , even white ... The more common “beaded foam is usually white , but can be Blue also ... “ a rose by any other name “ ...
Expanded polystyrene , expanded Urethane , expanded poly propylene , many types of foam to choose from in many densities ... some even considered “structural “ for the more common home building practices ...
It’s amazing one can go on the net and post inaccurate information to suit their business opportunity, and people believe it , but it happens every day ... Might as well be a political ad ... we don’t believe ANY of those either ...

Didn't say it was true or I believed it, just said it was interesting...
Actually it looks like Dow Styrofoam is listed as XPS & EPS depending on the site you visit. Strange way foam is marketed.

[/url]http://www.amazon.com/Expanded-Polystyrene-Foam-Sheets-qty/dp/B0054JDQQC/ref=sr_1_1?ie=UTF8&qid=1328881472&sr=8-1[url]

[/url]http://building.dow.com/na/en/products/insulation/rigidfoam.htm[url][/url]

[Larry C]

Or find the right coating regardless of the Foam ...

I guess that would have to be something breathable, maybe tyvek?

You know , we’re not building the Pyramids ... Just a humble camping trailer for we of the 99% ...

I thought this thread was an epoxy vs glue discussion, didn't know we were building pyramids. I guess I am in the minority on the epoxy side.

[Papi]

Hmmm... pyramid-shaped foamie camper...

[eaglesdare]

an A frame shell

yes, this thread was to discus the glue vs epoxy issues. as i stated there were blisters associated with an epoxied foamie as well as one with a glued foamie. as already mentioned, we do not know the cause.

its ok to be in the minority on the expoxy side

these threads are for anyone that is interested in a foamie build, its up to each individual as to what materials to use.

so back to topic, or have we talked all there is to talk about these 2 types of coatings?

[linuxmanxxx]

Well I reread the guide again and it seems he is basing this gas release from something he must have learned when he was working distributing dow xps. He states that it happens usually when the molecules are crushed then release the gas. Now we have to remember the guy is talking about surfboard construction which undergoes some seriously crazy pressures and forces which would easier cause the gas and bubbling and it would never happen with it being installed in walls or floors of construction.

I misstated it was heat caused but is caused under duress. Now with that hypothesis and the cinching of the straps we might have the reason for eagles bubbles. I still think the more flexible the glue the less chance of it happening since the glue would take a lot more pressure to fully release from the overall bond to the foam surface. Has to do with the shear properties I spoke about in threads before where the lbs psi it takes for the glue to fail and at what temps it is. With 2 hard surfaces with no flex like wood the tb2/tb3 would have a massive shear strength but with a soft flexible thing like foam would be a very low number. But the tests that have been done with the foam factory's glue which is a flexible glue designed around foam you see a shear strength much higher like the tb2/tb3 has with the wood.

And just to point out epoxy in different variants is actually a glue as well but in others is a surface layer/sealer/protectant.

I think something might be possible around the foamcoat stuff using some weird mixture in the powder instead of water and we'd have the cheap flexible hard surface we are looking for. I'm leaning with pure latex or enamel paint mixed with the powder and see how it does. The powder with coverage is cheap but that bounce stuff they put a mint price on for sure. Think if we get creative we can figure some cheap generic form of that bounce and then we are off to the races. Slap it on let it harden then cheap exterior paint over it and done.

[Oldragbaggers]

Louella
I have seen blisters on fiberglass sailboats the cause I was told was moisture
being trapped when the fiberglass was being laid over the gel coat
I have read about the filon (sic) sided travel trailers having de-lamination
I have built or help build two all fiberglass airplanes I have never heard about any of the hundreds of the same type having blisters.
the idea of using a device to poke small holes into the foam to allow the TB to penetrate into the foam and form a better bond sounds like a good idea.
If one wants a light weight trailer foam sounds like the way to go
whatever one chooses to use to apply the canvas be it TB or epoxy or paint all seem to work.
like you said time will tell what works and what doesn't what is easy to fix and what is just a big PITA.

Pete,

Those old fiberglass blistering problems occur only in hulls that were laid up using polyester resin. the same does not occur in hulls laid up with epoxy resin. Once blisters are repaired, using epoxy of course, usually the hull will be coated with an epoxy barrier coat and the problem will not occur again.

The blisters actually occur when water penetrates the gelcoat over time, then reacts with chemicals in the polyester resin which causes the expansion and blistering. I am not a chemist or expert so I can't get any more technical about it than that. But having owned a number of older fiberglass sailboats, I have repaired a fair number of blisters in my day.

Louella,

There is no doubt that there are many methods to achieving a nice, sound, attractive and watertight teardrop. Epoxy is one way, and would be my preferred way, mostly because it is a medium I am really comfortable with and I enjoy working with it. (I even like the smell of it. How weird is that?!?!) Do I think it's the only way, absolutely not!!

And I really like reading about others successes using many different methods. There are so many possibilities, and the creative juices really flow on this website. That's what makes it so much fun to read. If it was just the same old ideas all the time, we could read through once and never check back again. But I love that almost every time I sign on to this forum I learn something new or have a new thought planted in my little pea brain.

[eaglesdare]

[pete42]

Becky said "(I even like the smell of it. How weird is that?!?!)" I vote for really weird vs absolutely nuts
but I don't know how much you have inhaled.. .....joking anyone who sails is OK in my book

blisters I have first hand knowledge of were on a 30 foot non-such can't remember the year nor what kind of resin was used:

Non-such over priced, over built but very easy to sail having a single mast and the wishbone boom.

"old sea dogs are good people"

Pete