The last week or so has been a bit of a mad rush and things aren’t finished yet. We (my wife and I) are planning on spending Christmas to new years in the camper at Bryce and Zion national parks. That sort of means it has to be finished (or at least weather tight and usable) in the next week.
That isn’t impossible, but the punch list is quite long and some of the steps are complicated and hard to do alone (like gluing the sides). I’ve made a lot of progress in the last few days, but also had one big setback.
Passenger’s Side Wall
Installing the driver’s side wall skin was pretty hectic. I didn’t have a firm plan for clamping and it didn’t go great. Never the less, that wall is on and glued well.
Since this photo was taken, I’ve cut the door opening and fit the door so it opens and closes smoothly. That is a story for further down.
On to side 2. This time I had a much better idea how to clamp the side and did a lot more work before I had glue drying on the trailer. I pre-drilled 3″ holes around the perimeter for my long bar clamps and for short clamps in the galley. This time I could get good clamping force along the top edge if no-where else.
I used the same sort of clamping to try to pull the center of the aluminum in to the wall. This time I used 3 tie straps instead of one.
The only real catch was that I didn’t have enough 2x4s for the job. At $3 a piece, I should have had 12 instead of 6… You always need more than you have and they cost almost nothing.
If I ever build a second trailer, I’ll probably skip the sheet of plywood. I suspect I would have had better pressure with just the 2x4s.
This time I only let the wall sit 24 hours before unclamping. I would have liked longer, but our schedule won’t allow it. As with the first side, Some areas needed clamping after the main clamps were removed.
Luckily the carpet glue doesn’t really dry completely and if you apply force it grabs as long as it is tacky. I held the bottom the same way as last time and it worked fine. No surprise there.
Failure – The Rear Hatch
The rear hatch was my first curved glue up. I test fit everything, and also purchased another 12 clamps (I have about 40 now) so I could make sure the entire perimeter was well clamped. I applied ample glue and attached the aluminum.
The thing with .063 (1/16″) aluminum is that it is really rigid. I didn’t have a lot of options in alloy in the sheet size I wanted so I took what was available. I used 5052, which apparently is very springy. The sheets do not bend.
When I unclamped it, the edged pealed loose and only the middle section was really glued.
This might be a blessing in disguise. I couldn’t get a piece of aluminum large enough to fit the hatch on it’s own so I went with a piece that left a small strip on either edge (left and right) clear.
The theory was that the aluminum trim would overhand it and hide it. Turns out I measured the trim wrong… When I reinstall this later, I’m rotating it 90 degrees so it will cover the entire width. I’ll have a seam at the bottom right at the hatch handle which I will cover with a decorative element.
With a little scrubbing with mineral spirits the aluminum was glue free, ready to try again later on.
Prepping the Doors
The doors have been “blanks” up until now. I’ve got my windows here and I also need to lighten them and add pockets for insulation.
I’ll record more details when I assemble the second door, but here is the basic idea. The doors are a 1 1/4″ thick solid mass of plywood laminated from a 3/4″ sheet and a 1/2″ sheet. They are very heavy and uninsulated.
I cut the window opening using a jigsaw and cleaned it up with sand paper until the windows fit well. The window frame hides this opening so I didn’t require perfection. There is actually a recess dado on the inside since the windows I bought had a trim ring for a thinner door. Easy enough with the router and a dad bit.
The second step was to hog out 3/4″ deep spaces for insulation. That involved lots of work with a forstner bit and a straight bit in my router. I turned a large volume of the door into sawdust… It would have been way easier to cut these openings in the 3/4″ sheet of plywood before laminating it to the 1/2″ sheet.
The pockets are on the outside. The aluminum skin will cover them.
With all that done, I did a little final adjusting in the finished opening (block plain, sander) and then glued on the skin.
Gluing was easy with a small flat door plus a small sheet of aluminum. I used lots of clamps and weights in the center and expect no issues.
Fresh off the failure of the rear hatch, I decided to tackle the lower front of the trailer. It also curves. But, it is a much smaller (cheaper) piece of aluminum. I have drop-cuts (scraps from my order) that are big enough to replace it if I totally screw it up.
I decided to pre-bend it in the hopes that it would stay better. The fundamental problem I seemed to have on the hatch is that the carpet glue is stretch and flexible. That is a plus on the flat sides because it allows expansion without letting go. On curved surfaces, it means that the constant spring force trying to pull away will eventually win.
Anyway, I tried bending it by hand could could not exert enough force to bend it at all (not the totally flat sheet from the hatch…). Clearly I needed to get more forceful with it.
My improvised rig allowed me to apply a lot of force in a semi-controlled manner. I’m not going to lye, I was a little afraid of this rig. Bending the aluminum this far stored a lot of energy. If it had come apart, there was a real potential to have a sharp piece of aluminum flying…
I managed to put a decent curve in the aluminum that was close enough to the front nose of the trailer that installing it wasn’t to hard.
We (Adrian and I) did a full dry run clamping this and it really helped. I also used some “not-messing-around” polyurethane construction adhesive on the edges.
I still used the carpet adhesive in the center. My theory is that the stretchy adhesive will still help with expansion and contraction even if the construction adhesive doesn’t flex much. Time will tell.