A possible idea ... maybe ???

[GPW]

While discussing with friends the idea of recycling newspapers and what can we practically do with them ...The idea came up of using it to make a Foamie trailer or "skin it" ... So easy even Grandma could do it ... Don't have to paint it if you use the funnies... Just a consideration , thinking back to basics , an new trailer plan in the works ...
Plywood , planks , canvas, , cardboard , paper... It's all cellulose...

[TimC]

I attempted to "wallpaper" my first interior walls with topographic maps and road maps. Thought it would be a cool look. Well, the topo map's ink ran terribly when the glue penetrated from the back side. I don't remember continuing with the road maps. Might give it another test with my current build when I get that far.

[Pmullen503]

I've mentioned this before but I use kraft paper with waterbased polyurethane on my rc airplanes to cover the foam. I apply the paper damp, it will expand when wet and shrink back as it dries so pre-wet the paper or it will expand while applying with the WBPU and you'll get wrinkles.

Kraft paper is specifically designed to have wet strength where newsprint is pretty weak when wet. Kraft paper comes on rolls and in various weights from very light to grocery bag weight and heavier. You can apply multiple layers.

[GPW]

PM, I too used Kraft paper on foam for my wings too and it worked Great!!! That is till the FAA intruded and shut down our hobby ( over 250 gr. ) . And you can get really Thick Kraft paper too ...
I was thinking " Thrifty" ( use what we got )... Cheap !!! I'm on SS now ...
Think I'll experiment on the super cooler I'm working on ..see how it turns out ...

[GTS225]

Hmmmmm. Paper, plus tightbond 2 = paper mache?
WOW! An oversize pinata!

Roger

[Pmullen503]

If you used a glue (mod podge is a favorite) it has to be thin enough to fully wet the paper and it helps to squeegee the paper to remove liquid trapped under the paper after you apply it.

A couple layers of a heavier Kraft paper would be very strong and have a smoother texture that canvas. More work though because I think you would need two layers (up down and right left) otherwise you'd have to overlap the seams and those would show.

[Pmullen503]

.... That is till the FAA intruded and shut down our hobby ( over 250 gr. ) . ..

I fly at a club and we have a FRIA waiver so we can fly without remote ID. But if you don't have a club nearby (or don't want to have to join one), then you technically are violating the law. We have a group of fliers that fly foamies and drones at the local college grounds. The laws are unenforceable as a practical matter for responsible people. It's the idiots who fly their drones near active runways that ruined it for everyone else. LOS fliers have been operating safely for decades...

[Ottsville]

I have been rolling around the idea of sculpting chicken wire into complex shapes then covering in paper mache and exterior paint for a backyard kid's fort. But I've been ruminating on it so long that my kid has now outgrown that age.

[tony.latham]

Someone recently invented this stuff:





Easy-peasy.

Tony

[Pmullen503]

While I think epoxy/glass is undoubtedly the best treatment over plywood for strength and rot resistance, I'm not so sure it would be my choice for a soft substrate like foam.

Over plywood (which provides the structural rigidity and strength) a thin layer of glass and epoxy provides the waterproofing that the plywood lacks. The plywood supplies the impact resistance a thin layer of epoxy/glass lacks. It works as a system.

Over foam (which is the subject of this thread) the soft substrate can't provide the support the epoxy/glass needs to prevent damage to the epoxy/glass matrix from impacts. You really need a pretty heavy epoxy/glass layer to be able to support itself from impact damage.

The advantage that canvas, saturated with paint, has over foam is that it is remains flexible. So while an impact will dent the foam/canvas, the canvas/paint layer can't suffer much more deformation without tearing than fiberglass can and will, to a large extent, "self heal". Again, it works as a system.

[tony.latham]

Over foam (which is the subject of this thread) the soft substrate...

First of all, I was being a bit factitious.

I agree to a point. However, this is the method Burt Rhutan uses, called moldless construction, composite over foam, used in many-many aircraft designs. And they don't use much cloth or epoxy.




The polystyrene foam they use has a compressive strength of 35 PSI, while the Home Depot beadboard has 20. But we're not building airplanes.

I once drove over a 3/4" polyisocyanurate foam board sheet, and it barely left a tire imprint.

Tony

[Squigie]

Over foam (which is the subject of this thread) the soft substrate can't provide the support the epoxy/glass needs to prevent damage to the epoxy/glass matrix from impacts. You really need a pretty heavy epoxy/glass layer to be able to support itself from impact damage.

And you expect newspaper and modge podge to be better?

[Pmullen503]

Over foam (which is the subject of this thread) the soft substrate can't provide the support the epoxy/glass needs to prevent damage to the epoxy/glass matrix from impacts. You really need a pretty heavy epoxy/glass layer to be able to support itself from impact damage.

And you expect newspaper and modge podge to be better?

I didn't say that paper would be better than fiberglass. I said that a flexible covering like canvas saturated with paint would be my prefered covering over foam. Could you use fiberglass/epoxy? Absolutely.

I do have many years experience in RC aircraft where paper and some adhesive (WBPU, glue or mod podge) has been used by many people including myself, for covering foam wings. Ounce for ounce, it works better than fiberglass/epoxy. But in that area, less weight for a given tensile strength is paramount. Puncture resistance is not really considered because weight wise, it's too expensive. It's something you live with.

I was referring to the OP's idea of using newsprint over foam. That is a viable option to provide the needed tensile strength. But the weight of the covering is less important on a camper, it's a much smaller percentage of the total. Puncture/damage resistance however, is very important in a camper. That why I suggested at least two layers of a much heavier paper. Specifically, Kraft paper which because it is unbleached, is stronger than bleached papers (like newsprint).

This also fits the Foamy "ethos" which is fast, inexpensive and accessible to people without extensive fabrication experience and tools.