Not sure it gets any simpler than this...

[TJinPgh]

"Simple is usually a matter of relativity “ ... Perhaps .. Until you confirm there is something simpler than that ...

True enough. Although, if coming up with the absolute simplest design was the only objective, I'd probably go with a 4' wide and be done with it. I don't think that would work for me, though. So, there needs to be at least some trade offs.

Since I had mostly 3’wide canvas , I did mine in strips ... No problem with a modest overlap ... Nothing says you have to have one piece covering ... and if you think about , the more overlaps of canvas over canvas , the thicker /stronger the skin becomes...

True. But then, you also have more places for it to start to delaminate and leak.

I've also seen some pics where the glue starts leaching through the paint at the seams.

If you're using canvas, I would imagine that some seams are unavoidable. The fewer the better, though, IMHO.

If I went with the original Bunker style box design, I could go with the 10' wide canvas and only have seams on the ends.







The dark gray parts in these three would all be one continuous piece of canvas. The lighter gray could be done from a 3 yard piece cut in half.

An interior pic just to show the benefit of building it on a raised box. Leaving room for a lot of under-bed storage, a cabinet with counter space, an extra seat and still leave about 10 sf of open floor.

One could even throw a sleeping bag or air mattress down there for extra sleeping space if necessary. Could easily sleep three.

If you do go with the raised or sloped roof, Why not utilize the increased hieght at the rear and put a taller door in. Seems kind of pointless (to me anyway) to build standing room then have to bend over to go through the door.

Well, it was originally a factor of the pop-top where, even though you had 6' of height you still only had 4' of solid wall.

You could do it with the solid one. Although, I wonder if the structure would be more solid with a beam of some sort across the top of that part. Making another small wall for the extended part.

In either case, though, in thinking about it, I guess you'd have a seam there.

[TJinPgh]

Since people have used bed sheets for various purposes, I wonder how it would be to do the skin with muslin.

Chicago Canvas has "heavy natural muslin" in 10' wide for under $8 a yard. Wonder how it would hold up.

[GPW]

Not being one to argue I think you have it wrong about the canvas ... well proven already , NO seam de-lamination ... Glue leaching through the seams ... I don’t think anyone else has experienced that either , not on a Foamie ... are the proof ... and please don’t show us any pictures of wooden trailers , those are the ones with all the problems ...

After sitting through a year of naysayers , all that has proven to be untrue by all those that have actually built one ...

Bed sheets , Muslin ... kinda’ thin for the outer skin , fine for the inner ... The Skin IS the Strength of the trailer ...

[TJinPgh]

Well, I didn't say that delamination HAD occurred. I simply said that the more seams one has the greater the risk that it CAN occur.

As far as the glue leaching through. I'm not sure I understand the logistics of saying that it can (and has) happened on canvas covered wood and hasn't (and therefor can't) happen on foam.

Paint, contrary to popular opinion, is not a solid substance. Not for some time, anyway. If ever.

Things can leach through paint for YEARS after it cures. And, if you don't believe that, try painting a piece of green lumber. You'll be out there painting it year after year until every drop of the sap escapes from it.

Is there a way to KEEP the glue from leaching through the canvas? Possibly. Not saying that there isn't. A good quality stain blocking primer certainly helps.

I'm simply saying that I don't understand the reasoning of saying that it can leach through canvas if glued to wood but not if glued to foam.

Please explain.

[GPW]

Humbly , I can offer no explanation , because it hasn’t happened to anybody around here ... AFAIK , we’re the only ones congregating to build Foam trailers in this manner (on this planet) ... so if it hasn’t happened around here before , likely it won’t happen ... While a noble “few" came up with awfulizations’ about Foamies (in theory) , here in Foamie World , everything has been Good !!! Peace, contentment , Thrifty , almost No maintenance ... Foamies have travelled tens of thousands of miles now , been camped in , sat out in the Sun and rain , crossed scary tall bridges..... and the owners LIKE them ( and that’s Important my friend ! )
I think the ONLY thing we ever heard bad was the bubbles on Eagles trailer , caused by overzealous use of cinch straps ... probably still not fixed yet ... never was a problem , just cosmetic...


Still I don’t think anybody has taken the 500 lb. of Beer ballast seriously , save Mel and I ...

[Rosey]

I bought the muslin from the Chicago Canvas company to use on mine. I figured if it is not strong enough I can add a second layer and still be about the same price as canvas. It was the perfect width fabric for my wall size. The muslin will be alot easier to work with going around corners and so forth than the canvas. Good luck with your project!!

[GPW]

Rosey , I really believe the “reinforcing strips “ are the really important things ... doubling , or better the thickness of the skin on the critical joining areas ... on the broad flat areas not so necessary ... just no frozen turkeys , no hammers ... How is yours coming along ??? Anxious to see what you’ve come up with ...

[TJinPgh]

GPW,
I tend to look at things and figure "ok, this happened to this person. Is there a reason to think it won't happen here. If not, how can I prevent it.

I can't come up with a good reason why it happened with some people (on wood) and not others (on wood or foam). Something different must be in play beyond the medium upon which the canvas is placed.

Different glue? Different primer? Different paint?

What is being done differently for those it hasn't happened to compared to those it has.

Those are the questions I'd want to at least try to figure out before starting the build. It will be enough to come up with the funds the first time. I don't want to have to do it again.

Logic, to me, says, if it's the seams where the glue appears to be leaching through (when it does), simply find a way to eliminate the seams.

Simple enough to do in this case if the fabric is wide enough.

Your point about needing something stronger at the joints than at the open areas makes sense to a degree. Those are the areas that you don't want to twist and flex as much.

By the same token, as you mentioned, you would want the walls to absorb as much impact in the open areas as on the corners.

The tests that were done showing the comparison between canvas and fiberglass on impact resistance were helpful. I would want to run some tests with muslin, with one or two layers, to see how it would hold up in similar tests.

Rosey, you mentioned you bought the muslin for that purpose. Have you had the chance to run any impact tests using it?

Doubling up on it is certainly an option. Although, it would seem reasonable to say that even if doubling the cost of the muslin doesn't cost any more than a single layer of canvas, you'll also need to double the cost of the glue/paint to adhere it?

[Rosey]

TJ
I'm not really a tester I tend to wing it and see what happens It works for me. Based on my previous boat build, and the texture of the muslin. The cost of the paint to adhere it seems negligible, an extra coat of paint from the used paint place ($20 for 5 gal) shouldn't break the budget. Plus the muslin will be easier to wrap around curves.

[TJinPgh]

Ok.

I planned on using Titebond II to glue it to the foam, then paint after that. I wasn't sure if it would be necessary to use Titebond again to adhere the 2nd layer or if paint would be sufficient.

I didn't see a weight rating on the webpage... as in ounces, like they do with canvas. They just said medium and heavy weight.

Which did you order?

Would just be curious if the heavy weight stuff might get too bulky if a second layer was necessary.

[TJinPgh]

I need to see if there is a place around here that has used paint cheap.

The only place I know of that deals with used stuff is Construction Junction, but their paint isn't that much cheaper than going to someplace like WalMart or HD. And tends to actually cost more than the Home Depot "oops" paints.

Last I heard, they don't even take used paint any more. They just buy paint from someplace that does... already mixed to specific colors.

[GPW]

TJ, see if there’s a Habitat store near you ... and you can adhere the cloth with the paint , no T2 necessary at all ... It’s actually reported to stick the cloth down even better than the T2... and less to buy ...

If you browse through my Album , you can see some impact testing with a big sledge hammer ... Foam and canvas is tough stuff... damage , unlike wood , localized at the point of impact only .. Repairs , if needed , would be very quick and easy ..

[TJinPgh]

If you're not using glue that would probably explain why there's no bleed through, lol.

[GPW]

I did use T2 on the skinning and GG (assembly) , no problems ... just everyone seems to think the Latex paint sticks better ... There was some testing ... (Big Mike )

[TJinPgh]

So, we're talking a water based latex primer of some sort (Zinzer?), followed by a latex paint. Then an oil based top coat?

Hmmm.