Was skyline now Mercury, tear inspired camper for six

[rowerwet]

destructive testing

the edge to face bonds broke easily then I found the glue was still wet over most of the bond, the packages say 24 hours to dry, TBII had 48, and PL300 had 72.... definitely going to dowel all these joints in the foam, and give them plenty of time to dry in the hot summer sun.

face to face bonds were slightly better, of course they were clamped over the whole length and the glue bond was much thinner, it was still wet in the middle. the PL300 actually broke the foam, but still not impressed.
I will only use these glues for the joints between panels (roof to wall, wall to floor, type)

gluing to plywood gave me what I wanted to see, broken foam, even where it didn't break it tore the foam it was glued to away from the block. Since the wood absorbs water this makes sense.
No clear winner here, but both make me happy!

bad news here this test explains a few issues I've read about on the big thrifty thread, unless the skin is roughed up to give the glue/paint tooth, the sock isn't really stuck to the foam. On my ply tear the paint takes top layer of ply with it when the fabric is removed.
From what I can tell, TBII socked foamies unless well bonded to the foam, actually have a hard skin that could stand on its own in whatever shape the foam molded it to. The TBII sample was stiff and didn't want to stay bent.
PL300 could work, but over a whole skin it would be expensive, hard to work (very thick out of the tube) and just as soft as glidden gripper once hard.
now to test some foam roughing methods

[rowerwet]

Good luck and build the book shelves keep mama happy!!!!

Oh the Mrs is quite happy, spent most of today putting the finishing touches on her latest big project, redoing the down stairs bathroom...

[clermont cubby]

Oakinteriors:

Thanks for the links. Great foamie kayak builds.
Larry

[GPW]

Re: abraded foam ... True the canvas sticks better to roughened up foam , but then I always sanded mine to get a better finish anyway , factory foam is not exactly always smooth . The canvas really stuck well to the beaded foam board , with it’s already rough surface... but that got sanded and vacuumed before canvasing ..

One of the good things is , once the canvas is applied and painted it actually shrinks around the foam ... making a tighter fitting sock ... The reason we always stretch our canvas slightly when applying it ... stretching and smoothing ... Sometimes that can backfire ... On the FoamStream , we watched a seam actually move over 4” as it dried ... we should have left some extra material on the ends and trimmed later, once dried and shrunk fully ...

[Mary C]

I had no problem with the canvas right on the foam, anyway now you know why we tell everyone to read the big thrifty thread the experiments have been done several times but we know you just wanted to see if we were off our rockers!!!!

We can sit back and watch

Have faith in us I promises we weren't like I said PL300 is expensive and It didn't do as good a job and some places broke even though I gave it 8 months to dry (wood on door) I thought the same as you. That is what it is made for. I didn't go with gorrila glue(GG) because I didn't have clamps, It does work but I personally don't have luck with it. Yes the canvas dries hard with the TBII the thing is that is what you want it not only makes the sock but the shell.

Mary C.

[rowerwet]

I know many have tested this stuff before, but before I sink money into a project I want to know how the stuff I buy works. I built three mice with the same material and glue I used to make my tear, $100 vs $2,000, now I'll build a foamie mouse and if it all goes good, then a foamie tear, and ultimately the mega foam.
It isn't like this has been done to perfection with glues exactly made for foamie construction the way marine epoxy has been perfected for wooden boat building.
Bought my first three 4x8 sheets of 2" foam tonight, $98, I thought foamies were supposed to be cheap!
(my current tear walls actually cost more, 2 4x8 sheets of sureply $20 each, many feet of 1x2 0.50/ foot, 1" foil faced foam board $10 per 4x8 sheet, many tubes of construction adhesive at $5 a tube) and that was just to make one side! easily $98 per side, so I guess this is cheaper.
I just wish it was that blue green from Lowes instead of Pink from the depot...
the test pieces were small "crafts' pieces, 2'x2' they sell in the stores near the bigger stuff. took 5 stores and a web search to find 4x8 foam

[ghcoe]

I do believe I read somewhere that in the foam manufacturing they use silicone as a releasing agent. Good to sand the foam or wipe down with alcohol before using glue or paint.

[Mary C]

Row, just given into the usual no hard feelings I'm just saying and after doing such a good job on the thread it just seemed like you would have not been in doubt, but I thought you were building a foamie TD not a boat. now that I don't know anything about. I plan to make a boat one of these days just a foam fishing thingie I am going to glue 3 pieces of foam together and in the middle put a box of foam to sit on, gonna cut the back straight and put a well for the battery and the electric motor. I figure the main thing is to make it thick enough to float. SOMEDAY.............I will..... Iwill

Mary C.

[mezmo]

Hi rowerwet,

If you haven't already done so, check out these Foamie section Stickys:

Web Sites w/ Foam Info For Tools, Techniques, Sources Etc..
viewtopic.php?f=55&t=44382

glue info for foamies:
viewtopic.php?f=55&t=44078

adhesion level of myriad samples
viewtopic.php?f=55&t=44801

Also check out linuxmanxxx's 3M contact cement experience. For foam
to foam that and the commercial foam glues seem the best to me,
but everyone has their own view.

Cheers,
Norm/mezmo

[rowerwet]

Mary, no hard feelings, I'm just a person who has to see it for myself, hands on. Reading the big thrifty thread has helped, but until I try it, I don't know for sure. Kind of like the "tell a man there are billions of stars and he will believe you, tell him there's wet paint and he will touch it..."
especially since the more I read the big thrifty thread the more I see many different ideas being tried instead of one "this is the way" theme coming out.
Thanks to my testing I thought of a possible better way to make sure the seams dry all the way through when joining foam to foam while drifting off to sleep last night. I'll test it and let you know how it goes, best part is, if it works it will be cheap and easy.

[rowerwet]

what I'm really trying to wrap my head around is how much weaker a foamie is. my current tear is poly construction adhesive and plywood, the adhesive is tougher than the wood. To make a joint fail takes more force than could ever be expected unless I crashed at highway speeds (and even then...) and when the joint fails it tears the wood, not the glue.
my canvas and paint sock also only fails by tearing the wood, not the paint.
A foamie by comparision is very weak. The foam tears super easy (no big shock there) but then I find the sock isn't really stuck to the foam worth anything, the real "strength" is from the sock being glued to the plywood floor, locking the foam bits in a "balloon" of TBII . I know I can dowel all the foam joints together to make them stronger, now I just want the sock to be stuck to the foam better.
Must be the airplane mechanic/nut in me, I like everything as strong as possible, but also as simple and light as possible. Got to remember this is only a tent... I keep thinking bomb shelter...

[GPW]

Row , the basic problem is , the glue (if properly cured) will always be stronger than the foam ... the foam will always fail first ....

Take a foam box .... not very strong eh ? Then take a tent , not strong at all ... Marry the two and you end up with a structure stronger than both alone. And it’s lightweight, and doesn’t rot or delaminate. The Foamie' concept...
True, the adhesion between the foam and the fabric is important , and no doubt there are many specialized glues out there that this humble gathering is yet to explore , perhaps due to great expense or complexity of application, that would do a fine job of sticking the two together. Their existence is obvious by the many commercial products where foam is adhered to some other material .
But for we “homebuilders” , a suitable compromise was found (and it was cheap) . The idea is to use readily available glues for the application that suits them best ...
We know TB2 used to glue panels together as in a lamination takes FOREVER to dry completely inside ... IMHO a bad use for TB2 , which is much better for joining panels , with a smaller surface area to cure. Something like Great Stuff or Gorilla Glue would be better for laminating , though messy and expensive ...
As for adhering the canvas , of the many Foamie’s built now and the thousands of travel miles they’ve accumulated, we’ve yet to hear of a failure of the canvas to foam structure... So what we do might not be theoretically Perfect , it certainly is Good Enough !!!

ON Plywood : plywood is great stuff ... in the 1950’s ... Today we realize it’s limitations and the tendency to fall apart in exterior situations, (especially when bent) ... The problem with plywood is it’s made of wood ... Now in reality , wood is made out of little tubes of cellulose all glued together ... these tubes are how wood grows , conducting vital fluids and nutrients from the root system .... If you shave wood to make a veneer , you end up with little tubes running from one end to the other, and many open ended tubes where the grain has been violated. Now you stack the veneers perpendicular to each other , and you have a panel of wood , where water can get in from any end . The little tubes STILL able to conduct fluids... (it’s their job eh? ) And these fluids can travel at great lengths into the wood , weakening the bond , by swelling the now dried wood , and providing a way for cellulose eating bacteria to enter ... If you doubt the tube scenario , take a board of red oak , put one end in water and blow in the other end .... Yep ... bubbles ... some woods are more porous than others , but at least with a board , you can seal, the ends to prevent water intrusion .
I’m finding a preference now for materials where the tubes are arranged randomly and are short , so they cannot conduct water very far into the wood. Our recent experiments have included Gray Chipboard and OSB flooring , both of which worked as expected, and were submitted to conditions which would swell and delaminate plywood.

This Game of Foamies , is all about making wise choices of materials to do a specific job... much as with any other worthwhile project!!! Foam itself is just part of the Equation ...

[rowerwet]

for all my reading in the foamie section, I somehow missed the basic weakness of foam I'm still committed to the lite side, I just imagined foam was tougher...

[GPW]

And then there’s EPP (expanded polypropylene) foam , which comes in many densities , and is used for things like car fenders and football and bicycle helmets.. It would be a Super nice foam from a structural standpoint , but requires special glues , and doesn’t like paint ... That and it’s Very Expensive, and relatively difficult to find ... I’ve used it in the past to make relatively crash proof RC planes , and it really is TOUGH ... !!!
JMHO a bit “overkill” , since I made the FoamStream out of the weakest foam , bead board, and it’s just fine ... but to compensate for the weakness, we made it THICKER (3.5” thick) and used HEAVY 18 oz. canvas over that ... Essentially a very Heavy duty tent over a Beer cooler ....

[rowerwet]

don't laugh... I'm testing another idea, how to get the glue to dry in the middle of the joint.

first I perforated the foam to give it plenty of tooth, then I used my latest crazy idea, a "wick" to carry the solvents out of the joint.