Epoxy/Styrofoam Test Panels

[GPW]

Then just make the skin stronger, right??? Thinking the paneling inner wall on the bigger Foamies will add Tremendous Strength, that alone ... Lots of Thrifty Alternatives...

Time to retire for the evening ... CU in the morning ... I hope !!!

[Conedodger]

I think the only important thing is joints and making sure they dont move, as one they move the T2 cracks and there is a loss of strength.

GPW's drawing showing ply on the inside would work but I think it only has to go up the side a few inches to spread the load enough. The chance of a full foam sheet with a T2 / cloth covering breaking is very small as the load is spread over a large area but it moving at a right angle joint thats just 2" wide is more likely.

GPW: What would you use as glue to stick the ply (GG or T2)

So something to spread the load over a bigger area to stop the movement is all thats needed.

Wobbly: Have you tested the difference between GP Resin and epoxy? and have you tried GP Resin on foam as i understand it eats it?

I have been told by a boat builder that epoxy can stand 4 times more on a joint than GP

Colin

[Conedodger]

On GPW's build



The only week spot, and this is JMHO is the fllor to the foam.

In an emergancy stop or accident the trailer and the floor is not going to move but something will, think of it like something loose in your boot (trunck). Be it stuff inside the tear or the whole foam section. However if the load is spread so it goes into the floor it will go nowhere.

You must be very happy with your tear so far GPW

[GPW]

Quote: "In an emergancy stop or accident the trailer and the floor is not going to move but something will, think of it like something loose in your boot (trunck). Be it stuff inside the tear or the whole foam section. However if the load is spread so it goes into the floor it will go nowhere. "
One might think the same could be said for most any trailer ...

[Conedodger]

GPW: You are right but then most trailers have a fixed bulkhead and something holding down the load.

Please understand i am not saying that a cloth joint from floor to foam is not good enough just that its one of, if not the most critical joint on the whole build and if it moves, disaster may follow.

On farm trailers most of the load stays put by its own weight, you use a sheet to hold in the load that would fly away and ropes or straps to keep the load on the trailer if it should slip. They all work together.

Yours is a low, small, light, shaped and well made foam box and should not take a lot of securing to a trailer but its my understanding that its held to the floor with cloth and PVA so if this fails there is nothing else.

You and Eagle have a lot of people following your amazing ideas and you both are making it look so easy to build one that more and more will try.

Even a silly old fart like me is going to build one, something before reading your posts I would not have even thought about doing it.

My point is that some of the plans are getting higher, longer and having weight added off the floor such as around doors, windows and roof spars so they may well no longer be a little light foam box, and as such if they are heavier those building them may well need to think up something extra than T2 and cloth to fix trailer to the foam.

[eaglesdare]

in my build i thought a piece of wood was run along front to back. and the reason given to me for that wood is exactly what you mention. and they showed my how it would stop the foam from moving sideway, again it made sense to me.
but i went out to check it out and it is not there. now i am not worried about it, because of the size of mine. with the spars and bulkhead attached to both walls in my size tear it works. now over time i am not sure how the glue will hold up. so i think and this is only my opinion, that a piece of wood does need to be run lenght wise. in the first build i am just going to keep an eye on it, if i feel is starts to loose that bond i will just run that strip of wood. but i won't add it til then.

on the second build, i am going bigger and wider. i am pretty sure i will be adding that strip of wood.

the thing is i just don't know how long that bond will hold over time.

maybe a full lenght of wood would not even be needed. perhaps just blocks spaced out along the floor board? just like spars are added every so many inches. just add the floor joint wood every so many inches.

i really need to stop thinking but those wood blocks or whatever you want to call them, really might not be needed, depending on how other things are attached. for example if you have a bulkhead, going side to side, you would not need that floor joint there. if you have something other type of wall/support at the opposite end of the tear that attached both walls together, the again, you would not need that floor joint.

i am thinking that is why i don't have the piece that runs front to back. i have one spar on the floor that runs side to side and i have the bulk head wall side to side. so in my size that is all i needed.

ok getting another cup of tea now.

[GPW]

Cone' , I'm most concerned by your considerations , and must agree, that area has the highest stress in "normal" use... And with the increasing sizes , some additional reinforcing would be mandatory , which is why I'm on about the plywood/paneling inner wall which can be mechanically attached to the floor , then the foam fixed to that... That and the otherwise suggested "reinforcements " should provide ample integrity... One might even slot the floor for the ply wall epoxy that in then add the millwork (screwed and glued) then the foam ... It may even be possible to build a standard floor to wall connection , then just add the foam outside ...
Fiberglassing the entire area in question would lessen any doubt ... Messy , but less an area than glassing the whole thing .... and I still believe for the absolute Best attachment of anything to foam , the perforations will be the key ... JMHO

My little build is so small light , there's not really anything there so I can get away with "less" ..The slanted roof provides extra support , much as a curved roof would ... Don't plan on hauling much gear in it ... Just a little "sleeper".. as per the original plan ... The foam is gorilla glued to the floor , then the cloth plus doubler ... seems quite strong , the linen canvas was fairly hefty and incredibly stronger than the cotton ...

.,, and being an old Geezer, I drive slow anyway ... so no worries about wind shear ... not at 45mph..

[GPW]

Eagle , I'm sure that glue will hold up for a Long time .... I have guitars , furniture made with T2 and GG , many over 15-20 years old , good as the day they were made.. You can always add more wood/foam to it ... And with a round over bit , those wood strips could be disguised as decorative moulding ...
Somebody needs to get a perforating tool to test if the perforations actually work better , or is it just a fools errand...
The better we make it , the longer it will last ...

[Conedodger]

i have the bulk head wall side to side.

ok getting another cup of tea now.

I think this is the key. I will try to explain

Lets face facts its a big foam box and once covered with T2 / Cloth (you should give this mix a name) the box is very strong and bonds together well. Under normal conditions its not going to move but if it does it will go all at once. This mix is either solid or not.

Take two pices of wood and stick them at right angles, once dry they will stand a lot but if the joint moves its had it, 100% useless, 100% no joint.

Placing your ply bulkhead stops the movement of the foam box so in your design to have a disaster it has to break the T2/cloth to foor joint and break the bulkhead which is just not going to happen.

Maybe another way would be to make the back wall of your storage box the bulkhead. GPW could do that in seconds by removing the gap on his drawing.

I think eagle, in adding a bulkhead you have cured all my fears and maybe it should be suggested on all builds.



Oh by the way mine is white with two sugars please......

[GPW]

Depends on the tea eh ? Pray tell what gap ???

[Conedodger]

The white bit between the foam near the words shelf brace and word storage on your image.

The storage box would in effect become the bulkhead

By the way what program do you use for your drawings?

Regards

Colin

[eaglesdare]

milk and sugar its the only way for hot tea!

yes what gap?

but i think that is what gpw and myself have been trying to say, it really needs to be connected totally as 1 unit.

[GPW]

That's bloody Brilliant !!! Fix the box to the wall ... another supporting module to spread the load ... Aluminum box would be a Stout support eh! probably need the nose weight anyway ...


Honey , lemon(depending) and fresh mint , which I grow in the back yard ...

[Conedodger]

Did you miss this bit GPW

By the way what program do you use for your drawings?

[Conedodger]

Aluminum box would be a Stout support eh! probably need the nose weight anyway ...

You wait, I am sure someone will say what about a foam box......