Utility Trailer Top Tent - Foamie version

[WoodSmith]

I've been wanting to make a teardrop for years. I had ideas for a version that would include a bunk for my small children. Children who are now 19 and 14. Other things always were more important, but the ideas are still there. This thread is where I'm going to document the process of building what I'm currently calling the Utility Trailer Top Tent - Foamie version. The Roof Top Tents that every Overlanding rig on reddit seems to be sporting these days (for the low low price of between $1500 and Holy COW!) are one inspiration. I also watched this video series and thought it could be done, perhaps better, with foam. At one point I had read all of the big thread, and I continued stopping by for a long time just to read and be inspired by KCStudly's Poet Creek Express build. (Not that I am the right person to poke a man who got distracted by life, but KC, if you read this, I'd love to see you get that piece of art on the road.) Much of the work I'm going to cover to begin with was done years ago, but I took photos, with good intentions of posting it ... somewhere, just never got around tuit. So in an effort to explain some of the decisions that come later, I'm going to add them here at the beginning.



I still don't yet have the money that I can justify spending on a trailer - but several years ago, I acquired a home built utility trailer from my Dad. It is not an ideal trailer, but has the decided benefit of existing, in my possession. The lights were sketchy, and I managed to knock one apart while backing the trailer up at one point. So I bought a new set of LED boat trailer lights, and a pair of steel light protectors from Agri-Supply, along with a new wiring harness. I stripped all the wood from the trailer, replaced the deck and tailgate with new treated 3/4 plywood (additionally treated with some Thompsons water seal from the clearance rack), and the side rails with new treated 5/4 decking. Stainless hardware was used everywhere, and I sanded, primed and rattle-can painted what I could easily access of the trailer frame in the process.



I wanted to add a couple things to the trailer light protectors - since they were going to stick out away from the trailer, I knew I would be brushing up against them frequently, and the sharp corners on the outsides looked like Greek Sirens - begging pant legs and flesh to come just a little closer. So I welded a section of 1/4" rod over them, taming their teeth. I also welded a pair of 3/8" coupling nuts in a vertical orientation to the back of the mounting plate. These are exactly the right size for the ubiquitous fiberglass marking poles available at your local hardware store for $2.50 apiece to slide right in place. A couple wraps of electrical tape keep them from falling any lower, and gravity holds them quite well in place. I've put many miles on these and never had them fall out even with lots of bumping (LOTS of bumping, more on that later) around. These provide the only reference that the trailer is behind the tow vehicle, and until I got cars with backup cameras, was the only possible way to back the trailer up. These were bolted to the frame with the same stainless bolts that hold on the top rails in the back of the trailer.



The lights were wired with a dedicated ground run along with the signal wires. Yes, the chassis is grounded at the tongue, but a soldered, sealed and shrink wrapped splice (as indeed all of the splices are) adds a ground wire for each side. The lights are boat trailer LED style, and as such come with a ground wire, rather than hoping, praying, or making sacrifice to whatever indifferent deity light manufacturers think will keep chassis grounds functional. The wires were run inside either split tubing, or where possible, flexible plastic conduit, which was fastened regularly on the underside of the trailer while replacing the deck. While I had the welder out, I added a brace to keep the front side mount of the aluminum sheet metal fenders approximately 90 degrees to the trailer. This had the added benefit of being a form of brush guard, a step, and another handy tie down location.

[WoodSmith]

The trailer did service hauling brush, doing dump runs and general utility trailer duties for a while. We decided to take a family camping trip, and with four people and a Chevy Equinox we needed more room for gear - the trailer was an obvious choice.

I built a hinged lid from a sheet of treated ply and the remains of the side rails to cover our camping gear, and provide a flat work surface while in camp. The dry rotted tires were replaced after they went flat 3 days prior to the camping trip. Then the tire store and I discovered that no amount of bead sealant would really seal the tires due to the rusty rims, they leaked down to flat in about 18 hours. So I packed my portable CO2 air supply (just visible on one folded cot in the loaded pic above) with the rest of the camping gear and checked pressure to the tires every hour of travel, and in the morning and evening while we spent a week camping in Hanging Rock NC.



The lid worked great. It was even a fairly secure place to store our gear when we left camp as I ran a couple of Torx landscaping screws into the framing and took my cordless drill in the car with us.

[WoodSmith]

While using the trailer in camp, I discovered that:

A) The lid was very heavy. and
B) Straddling the tongue and lifting the (very heavy) hinged lid so my wife could obtain some piece of gear from under the lid, had the unfortunate side effect of changing the balance of the trailer sufficiently to rapidly raise the tongue.

This was not ideal. After some ice, a few days rest, and returning home, I started looking for stabilizers and rims. The thing about rims, as is obvious in hindsight, is that they come in different lug nut patterns. The rims I had just bought new tires for are 5 lug rims. "No worries mate, she'll be right, no trouble!" The Australian accented voice in my head said. "What diameter is the lug circle?" asked the web page. "The make, model and year of the trailer should allow you to determine the lug pattern. Or find you axle or hub manufacturer in this handy table." Right. I'll just
lookup "Homebuilt, junkyard surplus, circa 1980's" in your handy chart, yeah, that entry says: "Measure it".

Turns out, they are 5 on 5.5" rims. "USED to be fairly popular, aint got none anymore" says the clerk at Agri-supply. E-trailer has a great selection of ONE 15 inch rim. I guess all this other stuff about offset and pilot diameter don't make a difference. I got online and added a pair of rear stabilizer jacks to the new rims that are what I can get. So I ordered them and aired up the tires, took the trailer to the shop, had them mount the new tires to the new rims and dragged the ratty old rims home to see what could be done with them. I managed to get one of them clean enough that it looked like it might hold a tire, shot it with Rustoleum primer and put it away for a someday spare tire. I could not get my grinder and wheel in the back of the rim due to the various shapes, but at least it should hold air. IF I ever put a tire on it.



The rim moved from place to place around the shop for a while, until a friend told me about a local guy who he was using to do some sandblasting. He offered to add my rim to the batch and I took him up on it. He also shot it with an epoxy primer when he was done blasting, and it looks much better now.

[Hamilton Felix]

Wow. We’ll be interested to see where you go from here.

[WoodSmith]

So I know everyone has been waiting with baited breath for me to continue this saga. I am actually making some progress. When I last posted, I had put on some new rims and a pair of stabilizer jacks at the back.

At home, my wife and I sleep in a king size bed. I'm hoping that a twin will be enough space for us to share when we are camping. So taking the measurements of a twin size mattress into account, I began laying out a platform to mount on top of the utility trailer.

(Parallax is weird, the dimensions of this are 56-1/2" x 81".)

I used some 1x3 poplar to make a frame, using biscuits and glue to join things together:


Measure the diagonals and get things clamped up square using a cargo strap to pull things into place:


I took (tried to anyway) advantage of a place I volunteer at that had a large relatively flat floor in hopes of vacuum clamping a layer of 1/4 cheap ply to the frame:

This did not work as well as I had hoped. the VCT tile had enough leakage through the joints that I could not really pull the vacuum that I wanted.

But we persevere. A flush trim bit in the router cleans up the edge of the plywood flush with the frame, and I found a nice big table to get things up off the floor to work on:

Visible in this picture are some stainless steel T-Nuts that I have strategically placed in the frame to use later to bolt the frame to the trailer. Embedding them inside the layer of plywood is a risk, if I drive a bolt too deep, I will de-laminate the plywood skin, but I hate having T-Nuts pop out, so I'm going to "Be Very Careful (TM)."

Cut the foam for a tight fit, squeeze out some glue and roll it around:


I used a drywall sander to give the foam a little tooth for the glue to grab:


And finish up with some newtonian clamps:


Lets see how this post looks...

[WoodSmith]

Repeat the process of cut, sand, squeeze, roll, clamp, wait, several times and we have a frame with one side skinned and foam in the cavities:

This image also shows four quarter circles in the corners of the center bit. This will become clear in a moment.

Since this platform will be sitting on the upper rim of the trailer, there is room underneath for storage and feet to be out of the way. So I laminated a table top from 3/4" ply and more cheap 1/4":


A rabbet was routed around the perimeter to allow this table top to inset flush:


And more skinning, now on the top side:


I even finally got someone to take a couple of action shots...




As with all projects, the idea in my head was a perfect gapless fit. I got pretty good, but there are some gaps that I'm not happy about that will eventually need to get filled.

[WoodSmith]

Apparently I neglected to take pictures of the construction of what I am calling the Pan. I'll take some pictures of it this weekend as I work on getting it coated properly with Themix.

I used a piece of one by pine that came from Lowes with a pretty good bow in it to trace a fair curve. I bandsawed and sanded the curve on three rafters, and for the front and back I cut a straight bevel of about 1-1/4" from the middle to each edge. While I had all the pieces individually accessible, I added a 1/8" dado to the outer 4 pieces, and cut a dado in the sides to attach the front and back.


The roof portion is one inch bigger on the inside dimension that the outside dimension of the Pan, this will allow some room between them for my future nylon side walls.

I traced and cut a blank of one inch foam to fit, and used gorilla glue to stick it in place. Roughly every 10 inches I drilled a hole and stuck a bamboo skewer coated with GG in to hold the foam in place:


In this shot with the second panel of foam in place, you can (sort of) see the skewers in a few places:


Here we see my arch nemesis, Gapadosis makes another appearance...

[KCStudly]

... I continued stopping by for a long time just to read and be inspired by KCStudly's Poet Creek Express build. (Not that I am the right person to poke a man who got distracted by life, but KC, if you read this, I'd love to see you get that piece of art on the road.) ...

I've been trying to catch back up on my "required reading/research", and really appreciate the kind words.

Looks like you are doing some very fine work yourself. Despite your humble trailer start, all of your work and descriptions show that the end result will be from good design and fabrication skills... at least I hope (you seem to be hinting at some sort of future trouble).

Just keep going a don't get discouraged.

[WoodSmith]

KC, I HOPE I'm not going to see any major issues crop up, I'm kind of doing this by the seat of my pants, but I sure have been running it through my brain a lot. This is the one set of problems I allow myself to think about while I go to sleep. Lots of them get solved by my subconscious brain - my biggest problem is remembering the solutions!

As I said, I don't seem to have any photos of the pan assembly. I did this early in the quarantine this year, trying to keep sane. I don't know if it helped or not...

After laminating the floor, I used some 1 by 6 pine to make the perimeter of the pan. This was glued with TiteBond 2 and screwed with stainless steel screws every 9 inches or so. Again, the goal here was a perfect joint between the floor and the sides, but the sheer size of the piece makes most of my clamps useless.



I was unhappy with the Gapadosis of the plywood skin on both the top and bottom of the floor, so I used a filler called Durhams Rock Hard Water Putty to fill any gaps between the various puzzle pieces. If anyone uses this, do not apply liberally with the plan of sanding back to fair. This stuff is HARD. Use a striking knife and get as much as you can out of the way before it dries. (I learned this lesson long ago, AND remembered, so I didn't have problems on this project!) After letting it cure I sanded it back to get things smooth and hopefully eliminate any intrusion points for water or critters.

I applied a coat of 25% Themix (My preferred name for the mix of urethane and paint thinner often called The Mix.) I used some leftover from my wood shop for the first coat, but sprung for a gallon of Minwax Spar Urethane for subsequent coats. A 50% cut coat followed, top and bottom.

Unhappy with some of the openings that I felt would allow sand, dirt, and any spilled fluids into the floor on the inside, I decided to try thickened epoxy fillets to cure my Gapadosis on the inside corners of the pan. I had some leftover System 3 epoxy that was nearing 10 years old, so I got some silica thickener, made some "peanut butter consistency" epoxy and tried my hand at fillets. I used a 3D printer to make a striking tool and fumbled my way through. (I have much respect for anyone who can do this without making a large mess, and especially for those who take their own pictures!) My 3D printed tool had a 1" radius and 1 inch long straight edges to help get the epoxy off the flat areas on either side. This had the unexpected advantage of getting just enough epoxy on the wood either side of the fillet for a film to be about 1-1/2 inches away from all corners. This shows up after sanding and subsequent coats of Themix as a slightly glossier coating close to the fillet.

The fillets were sanded (wet sanding worked best once I found some coarse enough wet/dry paper) and the whole floor pan prepped for more coats of Themix.



This worked well, and I wish that i had used the epoxy rather than the Water Putty on the plywood skin gaps. I think it would have bonded better in the long run. I feel like cleaning out the inside of the pan will be much easier now that there are no sharp inside corners to chase dirt around in. With the extra epoxy from the fillets, I made sure all the screws were driven past flush and filled the holes. This should keep water out of there.

The underside of the 1 by was ripped with a 10 degree bevel to provide some level of drip edge on the bottom, rather than letting water seep right around. I don't know if this is enough bevel to break the surface tension or not. I didn't want too sharp an edge because sharp edges just don't last long.


Speaking of sharp edges, at this point the corners and edges of all boards (save the drip edge) where rounded over with a 1/4" router bit - to improve the longevity of the Spar Urethane as well as reduce barked shins and fingers.

[Terra6]

Coming along and looking good. Nice.
Fyi, don't know if you've every seen or heard about these
Nice design
https://www.sylvansport.com/shop/go/