Mounting awning track on foam

[StanDahl]

I'm building a foamie slide-in truck camper for my Ford Ranger, and have a concern about mounting an awning track. I could go with aluminum, and cut slots in it to bend it, but think I'll get a pvc flexible track for a reason that may not be correct: I think it would be more likely to "give" and let go of the canvas in windy conditions - ideally before the whole track rips out of the side of the camper.

When mounting this, should I put wood backing on the other side of the 2" foam and screw it into that, or can I get away with using the big plastic drywall "screws" that you'd screw a smaller screw into? I would be afraid that the drywall screws would pull out and damage my canvas wrapped foam.

Here's what I'm thinking of doing...the awning track will be mounted under a foam eyebrow that will curve along the side of the camper. This drawing is just a circle, but it gives the general idea. The actual awning will be much larger, extending nearly the whole length of the camper.

Screen Shot 2016-11-28 at 8.27.44 PM.png (146.08 KiB) Viewed 1818 times

Here's what I've got so far, it doesn't show the lower parts, but you can see that it's teardrop inspired...

Day 31a copy.JPG (34 KiB) Viewed 1818 times

Here's an idea of what the finished product will look like...kinda:

Ranger camper 73 copy.png (103.66 KiB) Viewed 1818 times

[GPW]

JMHO, what we always recommended was a “Hard point” installed in the foam , with sufficient area and structure for the intended load ... Foam is NOT that strong for holding screws and shear loads ... A hardpoint can be anything, usually a wood or plywood plate inset and glued into the foam , then fabric covered . Maybe even some simple blocks attached to the wooden frame ...?

[ghcoe]

You might read through my working with flashing tread and see if you find any ideas. viewtopic.php?f=55&t=60303

[Pmullen503]

The big drywall screws are surprisingly strong, if you use enough of them, especially for shear loads. I added them after canvassing. For your awning, I think I like GPW's solution. Maybe even just dowels sunk deeply into the foam GGed in place and covered with canvas.

[StanDahl]

I like the round hard points idea. I assume that the mounting screw goes in from the right side?

George, I've been taking copious notes from your build over the last few weeks. I found a lot of very useful ideas there. I thought I got the big drywall anchor idea there? I've made a kerfing jig like yours, but haven't gotten to the point that I need to use it yet. I'm going to be making a number of specialty jigs for cutting foam based on that design. One will be for making half-lap joints to join two pieces on edge.

I really like how your canvas came out, both inside and out. I have to wonder how your outside edges came out so nicely despite being curved? I would think there would be creases as you folded the canvas over the edges.

[GPW]

PM’s idea is really good , just a fat dowel glued in .... and if you can tie it into some existing structure like your framework or an inner plywood wall ( some people prefer the "wood look" inside the cabin) then all the better .... It’s just all about spreading the load out over a large area using the great compression strength of the foam & fabric sandwich ... that and having a solid place for the screw or bolt ...

If you’re not going with a Monster awning , then it shouldn’t be much of a problem
... We’re still set up for the one pole awning ... easy for me , the old guy ...

[KCStudly]

I like the round hard points idea. I assume that the mounting screw goes in from the right side?

It could work either way, but the blocks would be much harder to find on the right side (as depicted^). I used the dowel technique for a lightly loaded application on my build (an afterthought when it was too late to use more traditional blocking) and what I found, as expected, was that the screws don't like to hold in the end grain nearly as well as when penetrating thru the side of the grain. Yes it is easier to just drill a hole and glue a piece of dowel in, but make sure you run the screw in, back it out, and harden the wooden threads with CA glue before putting the screw back in (kind of a PITA and still not as secure, IMO).

If you have a router, it is not that much trouble to make a small template to let in pockets for small blocks. The way I did the blocking for my rock guards would work for awning anchor points.

...making half-lap joints to join two pieces on edge.

Totally not necessary. I only see this adding complication and the opportunity to make more work for yourself. The foam by itself is not structural, per se; the benefit comes from its incompressibility over large areas, and therefore its ability to keep the skins separated. The skins (being located and stabilized by the foam) are where the structural strength comes from. Adding glue lap to the foam is therefore, unnecessary. Butt joints are fine. You will spend enough time as it is trying to fair the glue lines as it is (they always sand differently from the base foam, making that the issue you should be concerned with, again, IMO).

[Pmullen503]

One will be for making half-lap joints to join two pieces on edge.

I used a router with a slot cutting bit (http://www.rockler.com/freud-63-162-slotting-cutter-set-2-dia-x-1-4-h-x-1-2-sh) to make a 1/4" wide by about 5/8" deep groove in both sides of a joint and used a 1/4" spline to keep the edges aligned when butt gluing two pieces of foam together. (The spline probably adds strength too.) Keep the glue away from the surfaces and once sanded, you won't see the joint under canvas. Unlike a joint in wood, the foam is weaker than the glue joint. A half lap probably isn't stronger and is definitely harder to make.

[greygoos]

I'm building a foamie slide-in truck camper for my Ford Ranger, and have a concern about mounting an awning track. I could go with aluminum, and cut slots in it to bend it, but think I'll get a pvc flexible track for a reason that may not be correct: I think it would be more likely to "give" and let go of the canvas in windy conditions - ideally before the whole track rips out of the side of the camper.

When mounting this, should I put wood backing on the other side of the 2" foam and screw it into that, or can I get away with using the big plastic drywall "screws" that you'd screw a smaller screw into? I would be afraid that the drywall screws would pull out and damage my canvas wrapped foam.

Here's what I'm thinking of doing...the awning track will be mounted under a foam eyebrow that will curve along the side of the camper. This drawing is just a circle, but it gives the general idea. The actual awning will be much larger, extending nearly the whole length of the camper.

The attachment Screen Shot 2016-11-28 at 8.27.44 PM.png is no longer available

Here's what I've got so far, it doesn't show the lower parts, but you can see that it's teardrop inspired...

The attachment Day 31a copy.JPG is no longer available

Here's an idea of what the finished product will look like...kinda:

The attachment Ranger camper 73 copy.png is no longer available

KInd of reminds me of an old Gypsy Camper

[ghcoe]

George, I've been taking copious notes from your build over the last few weeks. I found a lot of very useful ideas there. I thought I got the big drywall anchor idea there? I've made a kerfing jig like yours, but haven't gotten to the point that I need to use it yet. I'm going to be making a number of specialty jigs for cutting foam based on that design. One will be for making half-lap joints to join two pieces on edge.

I really like how your canvas came out, both inside and out. I have to wonder how your outside edges came out so nicely despite being curved? I would think there would be creases as you folded the canvas over the edges.

No, not me on the drywall anchor. I do remember reading about that though. Not sure where I read it though.

Hope you find your jig to work as well as mine did. Sure made kerfing a snap.

I made a write up here http://tnttt.com/viewtopic.php?f=55&t=5 ... t=hot+wire on hot wiring jigs. Just so happens that the jig I was making was for joining two pieces of foam together. I think this would work great for a roof joint. It would add a structured roof beam inside the joint. Just apply GG into the slots, add wood and place on a flat surface and wait for it to cure. By adding glue just to the slots it leaves the edges glue free for ease of sanding but the wood would be incased in a GG making a strong joint and a structural beam for the roof and the same time.

I have no creases on the radiuses. There was even sizing applied which made the canvas even stiffer. A roller and applying water helps a lot in getting the canvas to work out in these areas. My rear radius was a bit harder to work out, but I just kept at it and eventually it worked out.

Thanks for the kind comments.

[pchast]

Dowels are an interesting idea. Especially as a retrofit drilled into the foam.

I think I would prefer a rectangular piece, using the long side opposed to
gravity splitting the foam. Especially when the insert can be planned.

[StanDahl]

Thanks for all the great replies! I think I'm going to prefer rectangular blocks, or a even a whole curved strip with blocks attached, on the back side of the foam. I figure a stud finder would help find them if I somehow was in doubt of their location - or just poking around with a wire! Maybe a nice piece of tightly layered baltic birch or something similar with some against-the-grain grip would be best.

That's good to know about the butt jointed pieces. I had planned to do the wood spline or a lap joint, but I'd like to avoid either one of those. My joints won't be in critical places, and butt-joints may be all that is needed.

I love that Gypsy camper - I wonder what it's like inside?

[GPW]

"I like the round hard points idea. I assume that the mounting screw goes in from the right side?” ... er, No!!! ... the plate spreads the load on the outside surface , under the fabric skin .

Like KC says , end grain is the worst for screwing or nailing ( like a a nail in a tube ) , an old modeling trick is to fill the hole with old time cellulose cement , we’ve used that for years with good results , but guess any glue would work ...

And eliminating the dowel , juat a block ( or thick Plywood) inset into the foam works , just make it big enough to spread the intended load stress over a fairly large surface , a job already shared with the outer skin ... and as a a matter of course ,we’d want to soak any wood exposed with "the mix"... just to be cautious , it will have a hole in it for the screw/bolt ... potential water entry unless well sealed ... Don’t want your awning pulled out because the hole rotted inside ...

Pre drill your holes in your blocks and through the foam then you can poke a bit of coat hanger wire through the hole to indicate where the attachment points holes are ...

[Don L.]

I lie the 1x on the other side of the foam, it will hold at least as well as the foam wall is attached to the rest of everything. I still can't picture how your awning will look but I know they can take some major stress from winds or collapsing from whatever.

Maybe some through connectors with fender washers on the inside, something like this; https://www.thehardwarehut.com/catalog- ... AjNs8P8HAQ

[KCStudly]

So the reasons I put the wood blocking on the same side of the joint to be clamped are:
1. The wood is more or less incompressible, at least compared to the foam. If you tighten the joint and the foam compresses, or takes a set over time then your fasteners won't necessarily stay tight.
2. If there is any slight relative motion in the joint, the foam around the fastener could become wallowed out or degraded, becoming a potential sealing issue... down hill spiral to rot.
3. Shorter fastener = less weight (okay, my build is no ultralight weight build, but it is an argument in the plus column!).
4. As mentioned previously, easier to find the wood telegraphing thru canvas (or FG skin).

The anchor points are adequately bedded in foam and backed up by the outer (nearside) skin. I see no advantages to putting a (less than full wall thickness) block on the far side. If in doubt, do a test sample and you will see for yourself.