Painted Canvas questions.

[Vajra]

Last summer, I was at a garage sale when the owner had for sale, some very old gliders. The trailers for these, appeared to be nothing more then wooden skeletal frames with canvas fastened on, then painted. These also appeared to be very old, as in 30+ years old from what I could find at the time on the planes. He mentioned he bought the gliders new, and built the trailers. Later after browsing through the sale, I went to ask him about the structure, be he had left. I tried days later but he was gone. Has anyone else seen this, or have experience with it? It looked very simply built. It was extremely light for such a long trailer. The areas unsupported between the framework, did have some slight flexing, but over all was fairly rigid. If he built these and never did much else to them, they were shockingly well built skin wise. It was dry inside... has anyone used this on a camper, or in a similar manner, if so, do they leak? I assume this is much like PMF, but only a lighter skeletal type system. How well would this work for a camper? I assume if you make a stick build, and skin it with canvas, paint it, and then insulate it, might be just as good as others? I tried looking up painted canvas trailers... but.. I just get Canvas paintings of travel trailer. - Vajra

[Pmullen503]

Do a search for "skin on frame boats". Now imagine a trailer built with such methods. I'd use dacron or polyester because you can shrink it to fit your curved frames. I've been working on a design off and on for some time.

I've seen a few examples of canvas covered lattice walls and fabric roofs or roll up fabric hatch covers. So it's been done. One problem I can see is insulation and condensation. You're pretty much in a tent on wheels.

[Vajra]

Thanks for the keywords... you know, any other time, searches would have dragged that up. AI is failing.

Yes, well what I was thinking is, based on what I had seen, you could make a standard stick frame, and do the canvasing. It wouldn't be that much different then skinning with the typical sidings. After it is all dried, add insulation like you would normally. The glider trailers I seen, it would be easy enough to install XPS or EPS between the framing. I don't think condensation would be to much different from other trailers. Or am I missing something?

I've started to wonder, what is the canvas was pulled tight, painted, allowed to dry, and then cut into a sheet. The canvas on the glider trailers I seen, were very stiff. I am sure they would flex, but, as a water proof panel, might have interesting results. I'm going to have to play around with that. I also wonder if different paints have different effects on the canvas, waterproofing and flexibility.

You mention Dacron on polyester, how do you shrink it? When I looked at videos and tutorials, everything is pretty much cut and staple, much like canvas. I seen heat applied once, but it was to melt heatglue bead to hold the fabric during a canoe build.

Tent, yeah... but much more rigid, and the idea of it being hardened... more appealing.

[GTS225]

That construction technique is not new. In the beginnings of aviation, the skin on an "aeroplane" was literally, cloth over a wood frame, covered with an acetone based paint, called "dope". While the dope dried, it also shrank the cloth, tightening it all around the framing. It took a bit to figure out exactly how to do it, without warping wings at the same time.
You might want to research "tube and rag" construction, as applied to homebuilt aircraft for some additional information.

Roger

[Pmullen503]

If you insulate then condensation shouldn't be a problem. If the panels are flat, then it should be easy to do when the canvas has been painted and dry. Painted canvas has been used as a sort of floor covering/rug. That would not be a bad choice in a trailer. That's one use for prepainted canvas.

Dacron shrinks with heat so the last step would be to go over the covering with a hot iron.

[Vajra]

Thanks GTS225! I will have to look that up. I know similar constructions were used back in the day. I am just surprised as well as it appeared to hold up, that no one uses it in current trailer builds, or at least, that I have seen. A great deal of curves are possible.

Interesting.. Yeah, where I am, it is far to cold not to insulate, even summer temps can fall into the 40's in areas I would like to go.

Dacron.. so if you heat it with a hot iron, I assume this is the last of the construction/skinning, but coating with paint or resin is still needed?

[Pmullen503]

Painting it makes it waterproof and protects it from UV.

[Tomterrific]

I think a canvas skinned skeleton is an intriguing idea. A lightweight strong skeleton could be engineered so the fabric would do nothing except give weather protection. I also feel condensation would not be a bothersome problem. Having enough ventilation and sleeping compartment volume would help. Insulation in winter would be a sleeping bag or better, an electric blanket. Summer sun heat would be reflected with bright white paint and the forementioned plenty of ventilation.

The cloth used in modern aircraft is Dacron. It is a synthetic with prestreched threads. By heating the attached fabric with a hot iron, the fabric shrinks tight. Although this would be light and conform to an odd shape, I'd consider cotton canvas for a traditional teardrop shape.

Another use I wonder for canvas is to repair a teardrop roof made out of faulty materials. Just stretch the canvas over with glue and paint. Seals the roof and keeps out water.

Tt

[jwlambert]

Morning, I had some experience with dacron stretching and fitting. Worked on an old harvard plane wing repair. It is structurally sound when used in conjunction with aircraft spruce. The spruce is a bit too pricey. Clear white pine would be an ideal substitute with all joints mortised.

Aircraft Spruce has all the needs should you undertake the project.

Cheers!
Aircraft Spruce

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[swoody126]

here'z a quick read on the process

http://www.duckworksmagazine.com/07/how ... /index.htm

sw

[Snaproll]

I doubt this is the same thing but, in the 50's I remember a neighbor built a small runabout boat and used a canvas material over wood for the front deck surface and then painted it.. I have wondered if this would be a good roof for a teardrop or tiny trailer. I haven't started mine yet but am just researching the forum for ideas..