Teardrops n Tiny Travel Trailers

Hello,

Temper fidgets, and the nice weather quickly fugits. Like others before me, I'm hesitant about the bond strength of canvas to foam using Titebond-Ii. Some of the earlier experiments with 6-8oz painter's canvas did not go as well as I'd like. There was very little tearout of foam when I ripped off the canvas, and it seemed the glue was either on the canvas or in the score lines of the foam (I had scored the surface prior to applying glue).

So now I'm doing tests with the 11.5oz Big Duck canvas. I scored the foam samples with a ripsaw to give it a 'corduroy' texture, and dampened the canvas. Then I applied glue full strenght, and 80:20 glue:water dilution. On another foam sample, I scored it and painted it with a bit of leftover Kilz (oil base) that I used on the cedar deck framing. After it's dry, I'm going to glue the foam to the painted surface, which has a definite primer toothy 'feel' to it. i'll let you know if it works.

My question is, as anyone applied Glidden Gripper as a glue-friendly base coat before gluing on the canvas?

I will be doing that with the Nookery this week.


Sent from my iPhone using Tapatalk

As i recall, you had a problem with delamination of the floor due to water intrusion. This advice might be too late, but on my deck, I made sure to fully varnish both sides >and all of the edges< of the plywood deck. I think that delamination often starts when water seeps into the endgrain at the edges.

By the way, exactly which gluing method do you intend to do?

I used Gripper to glue down my canvas.

I scuff sanded and pierced the foam, wallpaper tool. .
Then rolled gripper on th e canvas.
Rolled gripper on the foam.
Then applied canvas to foam all in one process.

It still appears to have worked very well.

Bob Hammond wrote:As i recall, you had a problem with delamination of the floor due to water intrusion. This advice might be too late, but on my deck, I made sure to fully varnish both sides >and all of the edges< of the plywood deck. I think that delamination often starts when water seeps into the endgrain at the edges.

By the way, exactly which gluing method do you intend to do?

My new floor has no wood. It is a canvas foam canvas and vinyl. I used full strength TBII for the canvas to foam after roughing up the foam surface for both sides. The vinyl is a floating type which will be the top layer of the connection to the trailer. I have painted the bottom with paint and will be doing a second coat with the exterior paint I will be using on the sides. To attach the canvas floor wrap up the sides of the wall I am planning on roughing up the painted surfaces and putting at least one coat of gripper on the newly added galley section prior to using gripper to glue the floor canvas to the wall. There will be more gripper in at least one more coat and then the exterior paint. Two coats most likely.


Sent from my iPhone using Tapatalk

Here are the results, from left to right. The sanded surface did not adhere well. The 'corduroy-scored' surface adhered well. The scored surface plus primer was spotty. I'll go with it scored, using the saw in the picture.



Sent from my SM-G920P using Tapatalk

When I was in college we had this one grizzled old shop teacher (metallurgy) that used a startling technique to drill certain important life lessons into us. One of the things he used to be adamant about and yelled out frequently was, "test 'em like you use 'em!". While I can think of a scenario where maybe a folded edge might come loose and then be exposed to road wind or a snag where it might peel back in the same way that everyone finds so easy to make fail; I think the more common modes of failure are likely to be punctures (first, then maybe gouging tears and/or abrasion if the trailer continues to drive past whatever caused the puncture), and/or shear, such as in a flexure situation (wind loading on the front wall while underway trying to bow the panel inward, standing or snow loads on the roof, leaning against the wall while siting up inside or sleeping, or the dreaded grandson kicking).

Why do I say shear and not bending? Well, when you bend a panel like this the outer fibers stretch and the inner fibers compress, so between each micro layer of grain they are trying to slip past each other to varying degrees, so if the bond between canvas/glue/foam were to fail it would be in shear (call it cleavage if you like).

So I propose that, rather than tearing the canvas back in a peeling action, bending the whole sample back and forth would be a more reasonable test. This would alternately put tension and compression along the canvas to foam joint testing the shear strength of the glue joint. (Incidentally, when I did this to my canvas sample I was amazed at how far I could bend it with no apparent failure whatsoever.)

Also, when making test samples, go ahead and use the opportunity to test the technique of wrapping the corners. It will give the chance to see what minimum radius can be adhered to well, would be more representative to how the full scale build would be done, and would help reduce the temptation the tester has to peel the canvas up.

As to puncture resistance, if I were a betting man and had an ice pick to wield indiscriminately, I would guess and rank our typical building materials from best to worst as follows:
aluminum over thin plywood
aluminum directly over foam
thin plywood
epoxy/FG
PMF

Since there is such variation in the possible scenarios (blunt vs. sharp, angle of attack, force/speed, flexibility of offending object, etc.) it would be difficult to quantify what is reasonable performance. I expect that aluminum would be the hardest to repair and have it look as new.

Well said!


Sent from my iPhone using Tapatalk

Recent removal of Gorilla Taped AC hatch indicated the paint , and primer would both come off down to the glued fabric surface which stayed somehow ...
Naturally there are many considerations with any material ... It’s up to us to choose the one that’s best for our needs , time ,skills, tools and budget ...

I used gripper as a base coat for my build. I used flashing for hard points and needed something for the TBII to bond to, since I did not think TBII would bond to the flashing. worked great.

Gripper, VERY GENEROUSLY applied for PMF glue-down to sanded foam, also for flat surface wood-to-foam applications (hard surface areas). In my own tests, it beat TB2 hands down..........GG for edge gluing of foam-to-foam or wood-to-foam. TB2 used for wood-to-wood only. Thinned TB2 for canvas hardener and sealer.