I’d been putting this off long enough. It was time to learn to weld, and make the roof-rack frame for the pop-top-tent.
Off to the local steel merchants to get some 20x20mm box section in 2.5mm wall, which would make up the base of the frame. Also some 100mm x 3mm flat bar for the legs, 40mm equal angle m12 threaded bar, and 20mm hollow round for the clamps, and finally some 6mm solid round to join the legs up and spread some of the load across the roof gutter.
Wanting to try and keep with the lines of the truck, I worked out that the rack to be 1.3m wide, this should hopefully avoid making it look too top-heavy and cumbersome when its fixed to the roof. Likewise the length should be 3m to allow space for the sleeping area and access hatch.
I cut the lengths to suit and laid out the design in the garage.
The edge of the frame tacked together.
And a quick trial fit with the help of my assistant.
Next to weld in the cross bars to provide support for the floor.
Another trial fit, and tacking the legs in place. This part involved a lot of trial an error, with tiny adjustments to the rack position and leg lengths.
Finally it was done and I could move onto the clamps. The hollow round would be welded to the legs, the theaded bar could then be bolted through these.
The threaded bar was welded to the angle section, this would form the clamp that would hold on to the underside of the roof gutters.
Another test fit, with clamps in place.
Ahh… so this is why they said you should clamp your welding material to something solid – it bends as it cools!
No matter, I rewelded those sections with the rack in a jig to get the bars straight again. Also added another strengthening bar for the overhanging section at the back. It wont have a lot of weight on it when its finished anyway, but its better to be safe!
I welded in some triangulation for the legs and all the cross bars, plus the 6mm solid round bar onto the bottom of the legs.
After refitting to the roof for yet another trial fit, and taking the truck over some rough ground to try and twist the body of the car (it doesn’t!) I was happy with its strength. Time for a couple of coats of black gloss.
Finally i fitted some neoprene tubing over the 6mm solid round bar, this should help prevent the rack from scratching the trucks roof. The clamps also got a covering of 1.5mm self adhesive rubber matting.
Next my attention turned to the flooring for the rack. I decided on 12mm marine ply which seemed to give the best strength to weight compromise I was after.
Each of the 4 ply panels got about 6 coats of Sadolin Superdec wood paint.
With the rack on the truck once again, it was time to fix the plywood.
The rack got a strip of builders external grab adhesive squirted onto the bars, the ply sheets were then place in position and stuck down. I then drilled through the ply into the rack before finally screwing in some self tappers as another level of fixture security.
The finished rack. For now.