when to canvas walls?

[Joe4Camping]

Hello all,

I'm at the point in my TD build where I'm getting ready to attach my foam walls to the subfloor of my trailer. My question: is there any disadvantage to canvassing the interior walls before they're erected? Seems it would be much easier to lay on the TB2 and bedsheets while the walls are flat rather than vertical. As long as I stay clear of any and all glue points (like all edges).

I plan on canvassing the exterior when it is all put together.

Thoughts?

[KCStudly]

That sounds like the best plan to me. However, some people have commented that the shrinking action as the fabric dries can pull and curl flat panels. So be aware of that. I don't recall exactly, but I expect this is most likely to occur on foam walls that don't have much if any framing included. Suggested ways to remedy this are to preshrink your fabric, and/or clamp the edges of your wall to work bench while curing (although the clamps may interfere with curing and/or leave marks); or to do both sides at "the same time". If you have a perimeter frame, or even just a shoe board (fastener board along bottom edge of walls), I would think this would be less of an issue.

On a simple, small foamie, with little to no framing this is one argument for going to the trouble of doing the outside skin first after building the cabin shell. Another way to avoid the mess and potential warping of installing just one side first, instead of using fabric, use paneling... thin plywood (like TPCE) or even paper chipboard, like GPW has experimented with. Those products won't shrink like cotton fabric.

[me&z]

Disclaimer:. I've never built a foamie. I just lurk, learn, and dream of my future foamie.

I know that others have suggested canvassing the interior before putting up the walls for exactly the reasons you mention. However, I think I recall that someone did that and then life interrupted and there was a noticeable bow to the walls when he got back to it. Maybe someone else can confirm my memory - I think it might have been the Big Pink build. But if so, it was eventually finished by another builder. And was a very sharp looking foamie.

KC types faster than I do. But apparently remembers the same potential problem.

[Joe4Camping]

Thanks for the advice.

I will bedsheet and glue the walls flat, with strategically-placed weights (with wax paper to protect the bedsheets) along edges to hopefully combat the bowing. Bedsheets have also been pre-washed, so that may help too.


We'll see!

[KCStudly]

I've had better luck using freezer paper. It has a plastic film on one side instead of wax, and it still lays flat (kind of like professional masking paper).

Wax can interfere with future bonding operations, and I had some funky discoloration when it was used around cedar (must have reacted with the tannin).

Plastic sheeting works, too, but the heavy mil stuff comes off the roll folded, and so has creases. The creases don't lay flat and tend to allow liquids to pool up, creating blobs. Shrink wrap works, too, but tends to crinkle up, leaving the same affect; raised ridges of glue.

[Joe4Camping]

Did not know about freezer paper, thanks for that tip!

I'm not too worried about discoloration, since we'll be covering it all with peel-and-stick wallpaper (affixed with extra 3M spray adhesive to prevent peeling .... maybe).

[mikeschn]

I did the side wall in a flat state, laying down on the floor of the trailer. I did both the inside and the outside on the same weekend, so I didn't have any problem with bowing...

Here are the sides, finished with a few layers of TBII.



Also painted the insides with a color from Behr called aged eucalyptus...



Mike...

[GPW]

[tomhawk]

This was described recently as well:
http://www.tnttt.com/viewtopic.php?f=55&t=70236&start=15.

Canvassing both the interior and exterior walls before assembly has some attractive features:

• Canvassing done on a flat surface is easier.
• Much of canvass application on the interior is done before it is enclosed and cramped.
• The foam becomes reinforced before it is required to bear loads. This may prevent some fractured foam wall issues.
• It appears the bowing/warping issue is solved.

It seems this is now a proven method for making foamie walls.
I suppose if the build involves complicated angles or curves using this technique may not be possible.

Is there any downside to this method for use in constructing a simple wall structure?

Tom

[GPW]

Tom , You’re right … many advantages making big “semi-finished" parts and then just assembling them later … Covering alone is so much easier flat on a table … The Newton effect keeps everything steady … Painting is so much easier too ( no runs ) … Many advantages …

I’ve said many times now , if I was 40 years younger ( ) I’d start a little Foamie trailer business , making/painting large parts on big flat tables and then assembling them as discussed … probably the best way for “mass production “ …

Covering a completely finished standing unit can be a real tricky Job … ( ask me how I know … ask anybody here ) Flat on a table … EASY !!!

Curves just require some stretching or sometimes cutting “gores” like a basketball …
Down side ??? Not really … makes final assembly so much easier … and skinned foam panels like this actually seems to last longer and be easier to handle than what's available on the trailer market … and no woodshop or exotic tools needed … Cheaper too all around (Thrifty) …. materials ,ease of construction, durability , longevity , tow-ability , and being so light , you can haul more of YOUR STUFF along !!! We’ve been at this for years now and see no problems with the materials , as long as we build it right , it’s all Good .. Haven’t heard many complaints from others …
And top this …. Even GRANDMA’s have built Foamie trailers … TRUE !!! No down sides we can think of ?

[Joe4Camping]

I can understand skinning the inside of the walls disassembled. However, I thought to skin the outside you'd want to build the structure first, so that you can overlap the outer side wall skin onto the roof about 6 inches, to really clamp the entire unit together. If you skin the outer disassembled, then you'd just have reinforcing strips to join and seal the sides to the roof section. Is that enough? I'm curious about folks' thoughts on this.

[LostCajun]

I can understand skinning the inside of the walls disassembled. However, I thought to skin the outside you'd want to build the structure first, so that you can overlap the outer side wall skin onto the roof about 6 inches, to really clamp the entire unit together. If you skin the outer disassembled, then you'd just have reinforcing strips to join and seal the sides to the roof section. Is that enough? I'm curious about folks' thoughts on this.

Me, too....glad you asked...

Seems I read what you understand at least a thousand times, that the 'whole' skin gave the assembly its strength....I would think that meant at best one piece does the whole thing, slip a sock over it with the hole in the bottom kinda like with a a little six drawstring area under the bottom....

Then I thought the next best thing was six inches under the bottom and up and over the top edge for a few inches...

But, it is looking like just overlap its and pieces like crazy as long as one likes the look? and one makes the sock?

As long as one gets a good bond....everywhere there is overlap? Then maybe everything is peachy?

So.....to accomplish this....and I am confused beyond hope....does the bond need to be fabric to fabric with the bonding agent?.....make all bonds before changing agents? Although if memory serves me right....some switheroos are considered acceptable? So....which ones ARE NOT acceptable?

Can the fabric switheroo like crazy also? Go from canvas, to muslin, to fiberglass screen, to paper drywall tape, to fiber drywall tape, to plastic drywall edging? (should the edging be on foam, then covered by fabric? or the other way around? )....

Oh, well....I could test all of the above...but, I am already expired....I am just gonna slap some stuff on foam, and cover it with paint.

Craig

[GPW]

“ I am just gonna slap some stuff on foam, and cover it with paint. “ That’ll work !!! That’s how I did my Foamie #1 … ( whatever I had )