Build started//Sub 600 lbs / 2 months to build / aerodynamic

[ghcoe]

You should be fine. I think a Harbor Freight trailer is way too much trailer for the foamies I build. They are what I can get for a good price though. I think a A frame like for the Pico Lite would work just fine for a foamie http://tnttt.com/Design_Library/The%20Pico-Light.htm . Foamie bodies are quite rigid similar to a uni-body.

[YannG]

George, I went through your #1 Build. That was a great thread. I will be able to come up with something that nice but may inspire myself from a few post. Saw the hot wire made using a soldering gun. I will have to investigate a bit more on that. Do you find it difficult to install the canvas inside? Also, is there a benefit to canvas the interior of the foamie ( structurally and rigidity) or anything could cover the styrofoam such as wallpaper, vinyl wrapping?

[ghcoe]

Glad you liked the thread.

Canvasing the inside does add some extra strength to the foam, but is it needed I don't think so. I now canvas the interior walls and ceiling before I put the body together. Canvasing the inside once the walls and ceiling are built can be a bit difficult. I walked through how I did it in my #1 thread so you probably read through that already.

I have played with some other interior applications, but none so far have been as satisfactory as the canvas. Wall paper seems to peel with time and heat. Paper floor process works ok and looks pretty good in my kitchen. I don't however think it would hold up too well in a living area though. It punctures much easier than the canvas layup. I have not tried vinyl as of yet, but if the glue is good it might be ok.

[GPW]

Interior wall coverings … We’ve had great luck with a thin chipboard interior wall covering . Glues easily to foam with white glue ( TB2) and is very strong ( & puncture resistant ) , and a quick application of the mix makes it waterproof … and it’s inexpensive …

Makes a nice smooth wall … and a good base for paint , gluing maps , etc.
Eight years and counting !!!

[Pmullen503]

I would argue that you do want to cover the inside walls with a material with tensile strength. Covering both sides of a soft material like foam makes it much stiffer than just one side.

Necessary for a foamy? Probably not but easy to do and things happen over the years and the inside does take some damage so you'll want something more durable than just foam.

The one thing I suggest is taping the inside corners. This could be canvas, fiberglass, screen etc. Stresses concentrate at the corners so I want extra strength there. My foamie is a square back with full size barn doors so I can carry a small motorcycle. As such, it's like an open ended square box and can flex (and does) when the doors are open. So I made the joints carefully. I canvased the roof and inside walls before assembly and used an 8" wide strip of canvas to cover that joint. That is probably excessive, a 6" wide would have been fine, even 4" if applied carefully.

A long way of saying that even a skin of just heavy paper with attention paid to the joints is much better than bare foam.

[QueticoBill]

Agree with Pmullen. The strength is in the skins, not the foam. And most uncovered foam is very flammable as well.

[YannG]

Glad you liked the thread.

OMG George I am so sorry. I didn't mean to say I will build something as nice!!! I meant the total opposite.

I am not that cocky don't worry.

[YannG]

Agree with Pmullen. The strength is in the skins, not the foam. And most uncovered foam is very flammable as well.

The intention was not to leave the interior on bare foam but I just did not know if there was structural added value by canvassing the interior. But canvassing the interior before assembly seem to be a great approach and if taping the corners helps, I will do it too.

I will have to look at Pmullen barn door. I still try to wrap my head around how I will do the rear ( large door or hatch???). Since the rear will be square and probably lower than 4 feet, a hatch may be more in the way than anything else.

[Pmullen503]

My barn door is basically 4 ft square and hinged on the side. With no interior bulkhead, the long box flexes when the door is open to the side. The flex isn't a problem so much as wind catching the door.

I plan to rehinge it along the top which should solve the flex and the wind problem. For a galley with a bulkhead a couple feet in, I don't think you'd have a problem with flexing but the wind blowing the door around is still a concern.

[YannG]

Oh yes. The wind. Never thought of that. Makes sense.

[ghcoe]

Glad you liked the thread.

OMG George I am so sorry. I didn't mean to say I will build something as nice!!! I meant the total opposite.

I am not that cocky don't worry.

I knew what you meant.

[YannG]

Ran a quick test just for fun. I don't have the right type of glue so I only used normal Lepage yellow carpenter's glue. That held up quite fine to the EPS board I bought so TBII or Lepage Waterproof should work great. The only thing I find is that the canvas I have and used for the test is fairly thin. I do have 8 oz drop cloths here so comparing I would say that the roll of canvas I was given and tested with is probably 4oz. Question for you experienced people. Can I double wrap the foamie or if the second layer of canvas would not stick to the first one?

[pchast]

My laps with just paint stuck quite well.........

[GPW]

“ And most uncovered foam is very flammable as well. “ .. Is it really ? Anybody tested this … ? 

[QueticoBill]

Many labs have tested this. If you google "is foam board flammable" the following is typical":

"Rigid polyurethane and polyisocyanurate foams will, when ignited, burn rapidly and produce intense heat, dense smoke and gases which are irritating, flammable and/or toxic. As with other organic [carbon based petrochemical] materials the most significant gas is usually carbon monoxide. Thermal decomposition products from polyurethane foam, consist mainly of carbon monoxide, benzene, toluene, oxides of nitrogen, hydrogen cyanide, acetaldehyde, acetone, propene, carbon dioxide, alkenes and water vapor.”