Introduction: Installing a DIY Roof Rack for Solar Panels

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I wanted to add solar panels to my travel truck, which meant installing a sturdy rack to mount the panels on. Instead of buying an expensive roof rack system, I commissioned a simple steel rack at the SLO MakerSpace, and then installed it on the fiberglass camper shell using stainless steel hardware, DIY neoprene gaskets, and a lot of silicone sealant. The solar panel mounts are bolted onto the rack, so we can swap in new brackets if we want to upgrade our panels, or remove them completely and have a cargo rack.

We used:

  • DIY steel roof rack, 36" x 48". Thanks to MakerSpace Nate for the welding help!
  • Masking tape
  • Sharpie
  • Small piece of 2x4 to brace the camper shell while drilling
  • Mineral spirits
  • Black spray paint/primer for metal
  • Stainless steel hardware: flat washer, 1.5" button head bolt, locking washer, nut. We needed 8 sets of hardware for our rack.
  • 2 feet of black webbing, used to create permanent hangers for mounting a cargo net inside the shell
  • 1/8" neoprene sheet gasket, cut to size with scissors. I used this one:
  • Silicone sealant
  • Cargo net, for storing lightweight items.

Tools used:

  • Cordless drill
  • Spray paint handle - optional but highly recommended
  • Caulk gun
  • Scissors
  • Woodburning tool

Step 1: Drilling the Holes and Prepping the Rack

First, I put the rack on top of the camper shell, making sure to align it on all sides. Then I stuck blue painter's tape under each mounting foot, marked the spots for the mounting holes, and removed the rack. Here's the process we used for drilling through the fiberglass, which turned out to be super easy:

  • Drill through the marking tape, staring with the drill in reverse. This gets you through the top gel coat without cracking.
  • Use a fast drill speed, but don't put a lot of pressure on the drill.
  • Have a helper press a piece of wood up from the inside of the shell, to brace it against the pressure of the drill.
  • Drill a slightly larger (1/32") hole than your bolt or screw size. It was tough to get the bolt through several layers of washer/shell/gasket/rack without a little wiggle room.

I drilled all 8 mounting holes with no problem. Using the drill bit as as guide, I measured the thickness of the shell at 1 inch, so I needed bolts about 1.5" long to accommodate the mounting washers and nuts.

Next, I cleaned the rack and panel mounting brackets with mineral spirits to remove grease and dirt, then gave them three coats of black semi-gloss spray paint. The spray can handle is definitely worth the extra $5.

Step 2: Prepping the Custom Gaskets and Cargo Hangers

I measured the rack's mounting feet and cut out four 3" x 1.5" pieces of neoprene sheet gasket to fit under each foot. The gaskets need to be pre-drilled for the mounting bolt to slide through, so I made a little cardboard template and drilled the holes with a regular wood drill bit.

I also wanted to hang a cargo net from the ceiling of the camper shell, so we can keep lightweight items like down jackets handy. Since we're already drilling holes to bolt the rack on, I figured we could kill two birds by integrating a hanger into the bolt. Here's what I came up with:

  • Take a 7 inch long piece of webbing, about 1" across.
  • Fold it in half and sew down, leaving the last inch or so unfolded.
  • Using the washer as a guide, cut off the excess and singe the ends.
  • Punch a hole through the end tabs. I used a woodburning tool to burn right through both tabs.
  • Slide the bolt and washer on, and it's done!

I made four of these hangers so we can anchor each corner of the cargo net.

Step 3: Mounting the Rack and Cargo Net

After cleaning off the top of the truck, we set the rack in place and pushed the bolts through from inside the camper. While my helper held the bolts in place from the inside, I siliconed up a gasket, slide it over the bolts, then seated the rack on top and loosely added the lock washer and nut. We needed some wiggle room to get all 4 mounting feet attached, so we didn't tighten the nuts until everything was in place.

From the inside of the camper, the order was:

  • Bolt (4 with webbing cargo loop)
  • Flat washer
  • Camper shell (up to an 1 inch thick)
  • Neoprene gasket with lots of silicone on the shell-facing side
  • Steel rack
  • Locking washer
  • Nut

After tightening the nuts, I wiped up any excess silicone with a wet rag. We're planning to cut down the extra bolt length and add some more silicone to the nuts for extra weatherproofing.

Step 4: Adding the Solar Panels

Once the rack was secure, we attached the solar panel brackets and then the panels themselves. These pieces are just bolted on, so they can be removed easily. I didn't want to put another hole in the shell for the solar panel wiring until we're sure we like the configuration, so right now it connects to the inverter and battery bay through the sliding window.