Desert Moose logo painted on

[Dschroeder83]

Building my first trailer, a 5x8 squaredrop...thanks for the inspiration to use canvas and paint!

[saltywalty18]

This looks amazing. I am building my first tear.

Why did you use the canvas? Would it save cost, time, and weight by placing paint on the exterior wood?

Did you use putty on any seams before the canvas?

What type of glue did you use?

[KCStudly]

If I may...

Wood fibers are long and stringy and they bind to each other fairly well in the long direction because the fibers overlap each other over longer distances. Whereas in between the grain the fibers are only in contact with each other the short way and can split easily.

Especially when we bend plywood over a curve with the grain (i.e. the easy way) it puts stress on these weak bonds. Over time, sometimes very little time or immediately, and with temperature change, these bonds can weaken and the fibers can separate. Paint alone does not have the strength to hold these fibers together, so a flaw occurs that lets the weather in. Once the weather gets in the wood fibers absorb moisture and swell, pressing the fibers against each other, even deforming the surrounding fibers with the hydraulic force. Now when the fibers dry they shrink away from the split joint even further allowing more moisture in. And the cycle continues.

Natural cotton canvas fibers just happen to be cellulose as well, same as wood, so they soak up the glue nicely. However, the canvas fibers have been arranged to run in both directions, so it can handle stresses in both ways more or less equally. From statics (the engineering analysis of forces acting on stationary members) we know that it is the outermost fibers of any material or composite that determine the strength of said member in bending and/or torsion.

So long story short, the canvas fibers keep the wood fibers from failing the paint job, allowing the paint job to continue protecting the fibers. It is a composite where the sum of the parts is greater than the individual elements.

[desertmoose]

If I may...

snip...

So long story short, the canvas fibers keep the wood fibers from failing the paint job, allowing the paint job to continue protecting the fibers. It is a composite where the sum of the parts is greater than the individual elements.

KC, thanks, you nailed it.

Painted wood will fail. sooner or later. Small cracks develop, water gets in, and things get worse. Covering the wood with fiberglass, metal, etc is intended to keep the water from entering the wood. Canvas and paint does the same thing. It encapsulates the wood in a waterproof membrane, and keeps it off the wood.
There are no exposed edges or end grain to soak up water once cracks develop in the paint.

My tear sits outside in Nevada summer heat and winter snow. It's been there for 4 years now, and still is holding up great.

Another small benefit is, I used cheap plywood with lots of knots. It would have been a nightmare to smooth that surface to look OK after paint. Gluing the canvas on covered a multitude of defects, and gave a great surface for applying the finish paint coats.

You pick the way you want to build and do it, that's the fun part of making your own trailer. I know that if I ever build another trailer, I will use the painted canvas approach.

Sam

[saltywalty18]

Thanks for the input. Looks like I have more work to do ahead . . .

If I may...

snip...

So long story short, the canvas fibers keep the wood fibers from failing the paint job, allowing the paint job to continue protecting the fibers. It is a composite where the sum of the parts is greater than the individual elements.

KC, thanks, you nailed it.

Painted wood will fail. sooner or later. Small cracks develop, water gets in, and things get worse. Covering the wood with fiberglass, metal, etc is intended to keep the water from entering the wood. Canvas and paint does the same thing. It encapsulates the wood in a waterproof membrane, and keeps it off the wood.
There are no exposed edges or end grain to soak up water once cracks develop in the paint.

My tear sits outside in Nevada summer heat and winter snow. It's been there for 4 years now, and still is holding up great.

Another small benefit is, I used cheap plywood with lots of knots. It would have been a nightmare to smooth that surface to look OK after paint. Gluing the canvas on covered a multitude of defects, and gave a great surface for applying the finish paint coats.

You pick the way you want to build and do it, that's the fun part of making your own trailer. I know that if I ever build another trailer, I will use the painted canvas approach.

Sam

[Bent bike guy]

great job. I like the fabric covering. I am in the process of building my first tear using Sketchup. Planning to cover with some Dacron fabric I have but your use of Titebond2 I question. Titebond3 which is water proof would be a better choice. I plan to glue down the edges first then apply heat to stretch the Dacron then apply titebond 3 The Dacron was purchased to build a pontoon boat but never completed.
I like your storage ideas. Curious what does the completed trailer weigh? I am using a HF extra heavy duty trailer w/ 5 lug wheels. I think 1700lbs capacity.
Going with a 64 inch wide trailer (over the fenders) but only have 4 - 7 inches of storage area. Considering headroom, looking at splicing a 12" plywood to make body 60 inches tall and extending the plywood sides to bolt onto the 2 x 4 frame extension.
will post some drawings later.

[desertmoose]

great job. I like the fabric covering. I am in the process of building my first tear using Sketchup. Planning to cover with some Dacron fabric I have but your use of Titebond2 I question. Titebond3 which is water proof would be a better choice. I plan to glue down the edges first then apply heat to stretch the Dacron then apply titebond 3 The Dacron was purchased to build a pontoon boat but never completed.
I like your storage ideas. Curious what does the completed trailer weigh? I am using a HF extra heavy duty trailer w/ 5 lug wheels. I think 1700lbs capacity.
Going with a 64 inch wide trailer (over the fenders) but only have 4 - 7 inches of storage area. Considering headroom, looking at splicing a 12" plywood to make body 60 inches tall and extending the plywood sides to bolt onto the 2 x 4 frame extension.
will post some drawings later.

Thanks. We're happy with it.
A couple of comments, first, Titebond 3 is good, a bit more expensive though. with the pain on the outside, the glue doesn't ever get wet, so the water resistant Titebond 2 is fine.
next, I don't know where the application of glue to the exterior of the fabric came from. Glue is meant to attach stuff together, not be an exterior primer.
IMO, you should glue the fabric to the wood/ foam with titebond. Don't overdo the glue, you don't want the cloth saturated where the glue shows on the exterior. Then, after the glue has dried, Apply the thinned paint directly to the bare cloth. You get wonderful adhesion of the paint when it wraps around the fabric threads. Paint applied to a dried glue film won't have the same great bonding.

I don't know how you'd heat shrink the dacron if you apply it this way, but i don't think you need to. roll the glue on, position the fabric, and start gently pulling the edges till it's smooth. Don't pat the fabric into the glue until any wrinkles have been pulled out, then smooth the fabric down with your hands from the center outwards. you end up with a smooth bare fabric covering ready to paint. Let the glue dry before trimming the edges to the desired overlap, the brush glue around the edges and wrap the overlap around the corner.

The Desert Moose is big for a teardrop. 10' long, 5'-5" wide, with a 5' tall body. It's also made for off roading with 22" clearance from the bottom of the frame to the ground. The frame is 2" x 3" rectangular tubing and probably overbuilt. there's a 3500 pound axle with 2500 pound springs and shocks.

Overall, it weighed 1980 pounds with only the mattress in it when I registered it. Tow vehicle is either a Tacoma on road trips, or a Dodge one ton 4x4 diesel for off road. Plenty of tow capacity there.

Sam

[KCStudly]

Many discussions and tests have been done on this stuff. IIRC, Dacron, being a full synthetic, does not take the glue as well (if at all), whereas cotton absorbs it into the fibers locking it in.

[Bent bike guy]

I plan on gluing just the perminter first then heat shrink as they do fabric Kayaks. Then paint the Dacron fabric and the paint should bond the fabric to the wood. I have some airplane dope I could use but not sure if it is still any good. By heat shrinking the fabric will be really smooth.
Still no sure about the titebond 2 vers titebond 3

[Bent bike guy]

here are some links of what I am thinking. The second link has reference to waterproof canvas
http://www.gaboats.com/boats/

http://www.gaboats.com/tutorials/recanvas.html