It’s been another long interval, but I’ve started to make some real progress. I can see the camper’s shape starting to come together.
Since the last update, I’ve glued the inner skin on the walls. I’ve also cut the door openings. With that complete, I was able to attached the walls to the floor using pocket hole screws along the bottom edge.
I spent a lot of time debating how to attach the walls. Originally I planned to use bolts through the edge of the plywood, through the floor and into the frame. There are a couple of problems with this though. First, the space in the walls are only 3/4″ thick. That isn’t much space to drill a hole without compromising the structure of the wall.
Second, the bolt would run along the ply boundaries in the plywood. The direction of this grain is the same as the force of acceleration or deceleration. I worried the bolts would act to split the walls.
In the end, I ended up using pocket hole screws again. The walls are attached with a screw every 6″ for the entire 10 foot length of the floor. That is 20 screws per side. The screws pass through the plywood at an angle so do not lie along the ply boundaries in the plywood. They should not cause splitting like a bolt or screw parallel to those boundaries would.
The walls are also attached into the interior bulkheads. These bulkheads are attached to the floor with a variety of screws. There should be better than 60 screws holding the walls and bulkheads to the floor, all in sheer (they hold strong that way) and not tension (trying to pull the thread out which is weak for pine plywood).
Once I was happy with the wall attachment method and sure I as ready, I removed them one last time, added a bead of exterior grade silicone sealant as a gasket, and then installed them with all of the pocket hole screws.
Front Bulkhead and Front Cabinetry
As I installed the walls, I needed to start adding bulkheads to keep everything square, and also provide the front and rear walls of the sleeping area. The front bulkhead is simply 1/2″ plywood. There is a storage area in front of it. A second 1/2″ plywood bulkhead follows the front contour in 2 segments.
This bulkhead provides the front of the storage area, as well as the “back splash” for the storage area/counter top in front of the bed. Eventually, this upper front bulkhead will house the 120V power outlets, and possibly the heat pump connections.
I used a simple 3 lid arrangement to provide the top of this storage area. The center is designed to lift on its own. To remove one of the sides, you first remove the center. The entire area can be opened up and is intended to store bedding and other items.
The rear bulkhead is another torsion panel of 1/4″ plywood, 3/4″ plywood and insulation. It separates the sleeping area (conditioned) from the galley (unconditioned). It extends up to galley counter height. The design calls for a “zig” in the rear bulkhead to create more space in the galley by reducing the volume of the area above the foot of the sleeping area. Eventually the counter top will rest on top of this bulkhead and extend forward some.
A Cat Door
One of the design requirements from my wife was that we be able to take the cats along. The conversation went something like this:
Me: I want to build a DIY teardrop!
Adrian: Can you include a cat door and litter box spot so Narble can come with us?
Adrian: Great. Build away.
This isn’t the greatest picture (I can’t find the actual images I took of this…), but I added a cat door to the right side of the rear bulkhead. It will set just above the mattress near our feet. There is a simple catch and the door lifts out completely.
Eventually, once the galley is complete, the right hand cabinet will house a plastic litter box and be accessible via a locking door from the sleeping area.
In case you are wondering, this is Narble (really Inara, but with a face like that, she has to have a silly name too):
The front bulkhead provides some of the front rigidity, but there is more to come. The rear bulkhead acts as a major structural element making sure the walls stay square to the floor. The
With just these 2 lower bulkheads the walls are pretty stable even though neither bulkhead extends more than half way up their height. Once I have the upper rear bulkhead in, I expect the walls to be very rigid.