I have this inclination to DIY just about everything. Mom thinks I got it from my late Uncle Freddy, who used to build radios back in the 1930's and also work the electrical lines so as to get power without paying the power company in China.
I made a wooden rack to carry my canoe for my previous car, a Toyota Avalon, because the Yakima clips that held the Yakima rack to the roof edges slipped enough to put two canoes at risk. The wood rack for the Toyota was sturdy--not welded steel sturdy, but epoxied wood sturdy. I made it of 2x4 runners on each side with 1 x 6 x 4' load boards--a big rectangle that was a touch heavy and cumbersome. I'd glued and screwed it and it always felt rock solid. I don't have a picture of that rack--I've already scavenged parts for a rack for my new car. Can't keep this stuff around. I have enough clutter around here.
Why build a rack? I have the $ but I didn't like how the Tesla rack attached, where you slip a clip under the glass in four locations--online forums indicate the clip can bend or the glass can break if bolts or nuts are turned too tight. Neither Thule nor Yakima make a rack for my car. I could make another wooden rack or I could make it of steel, which I'd learned to weld recently. Questions I had: could I design one strong enough to withstand 60 mph with a canoe on top?
Well, I bought some 1/8" steel, but I thought using it as a 48" load bar, it wouldn't have sufficient rigidity. I bolted to it, the wood board scavenged from the rack for the Toyota.
Here we go with the process.
Buy steel for load bar, uprights (towers), and clips.
Decide where on the car I wanted the mount the racks.
Decide what other materials to use besides steel. Wood from the Toyota rack to stiffen the load bars,
Measure the angle of the roof at the attachment locations for the rack's uprights (towers). Cut tower pieces of 3/16" steel. (I bought more steel)
Cut bars of 1/4" or 1/8" steel. Weld to towers. Bolt to wood load boards scavenged from previous Wood rack. For future iterations consider load bar of:
angle iron
or 1/2 in. x 1-1/2 in. x 36 in. Plain C-Channel of 1/8" thickness
or 1/2 in. x 1 in. x 36 in. Plain C-Channel of 1/8" thickness below:
I've already welded for the rear, uprights of 1/8" x 2" to a 1/8" x 2"x 48" bar, too floppy by itself and
therefore bolted to the wood 1x6 used on the Toyota . Also, already welded for the front, uprights of 3/16"x2" to a 1/4 x 1.5" x 36" bar
(stiffer than 1/8" but still needs the wood).
Below: the first version of my design for the attachment hardware.
Below: A simpler, easier-to-build design.
I'm excited about my design. It's not pretty, but it'll work. The Toyota rack connected to the car more like the first picture above, but without the bolt G to pull the plate C up against the roof edge. Likely, the lower lip stayed up against the roof edge because the hole for the bolt was in the right place.
What I've done so far:
I've welded a 1/8" x 2" x 2.75" long arm/wing to each of the rear towers, extending laterally 1.75" above a bolt.
The clip. A 3/16" x 2" x 7" long plate with a hole that slips over the bolt. The bottom end of the plate has an 8 mm lip that wraps under the roof overhang. The top end of the plate extends up past the the wing and includes a 1" lip that hangs over the 2.75" arm.
I welded a similar arm to the sides of the front towers.
For problem #1, I welded a 1/8 x 1/2" piece of steel to reinforce the plate. It took 4-5 hours to weld, clean up and drill a hole. Things just take longer. Maybe they'd have happened faster if I'd written a list of actions instead of relying on a puddle of consciousness. Later, I concluded that laying a few beads of weld might have sufficed.
For problem #2, I placed a piece of cardboard edgewise to the roof where I wanted a front rack, drawing a line to match the roof line and made a custom plywood base for each end that would expand the fore and aft dimension of the base to 8 inches.
I wanted maximum contact between the rack base and the car roof to minimize stress and wear on the car. I didn’t want to make the bases by just cutting a rectangular block of wood and bolting it to the rack uprights. I would have to consider the changing angles in the fore and aft axis and the left-right axis. The first picture below shows how the roof climbs going from the side of the car to the center. The second picture gives a side view.
In version 2 of the rack I’d make the base in steel and attach a base plate (maybe 1/8" x 3/4" x 1.5") wherever the base touches the roof. To attach the base, I would have to either use a hinge or tack weld it on the car. Welding it on the car could be done if I took special care to properly drape the car to protect the car's finish from the heat or from weld spatter. The heat from even a tack weld could melt the paint. Conceivably I could use a large cotton tarp and put a piece of aluminum, foam or rubber inner tube under the base to protect the paint.
Next task: rout the top edges of both bases except where they touch the tower. Bolted the base to the tower. Add a rubber foot made of bike inner tube sections. The clips need to have their holes redrilled, because after adding the strips of reinforcing steel, I must have made the holes in the wrong places. Even without having bolted the clips on the rack seemed quite stable. It still bothers me that the back section sits on the painted part of the car instead of on the glass, which will never need repainting. A future task might be to cut and reweld where I want it.
Also done today: I cut a cardboard pattern for the base for the front towers. I’ll make the base of 3/4" plywood and will have a 10" length overall. I measured the angles between the front and rear contact surfaces and level--the difference was 5 degrees.
I quit at 4 p.m. to take a walk. No marathon session in the garage today. More tomorrow.
April 29, 2020
Next, extend the holes in the rear clips. Use the plasma cutter. Done
Mount the rack to the car and wiggle it around. Done. I've made something good here.
.One helpful thing about hybrid construction: screw holes slightly bigger than the thread diameters allow for some movement. One foot didn’t fully contact the roof--after loosening one screw, I improved the contact.
I've welded a 1/8" x 2" x 2.75" long arm/wing to each of the rear towers, extending laterally 1.75" above a bolt.
The clip. A 3/16" x 2" x 7" long plate with a hole that slips over the bolt. The bottom end of the plate has an 8 mm lip that wraps under the roof overhang. The top end of the plate extends up past the the wing and includes a 1" lip that hangs over the 2.75" arm.
I welded a similar arm to the sides of the front towers.
 |
| The front rack with the two inch deep base. Most people looking at this wouldn't think it very stable. If I had drawn before building it, would I have thought it stable? Probably not, considering my excitement at just being able to do it. |
April 27, 2020. I finished with the clip and bolted the racks to the car. It had two problems.
1. The 1/8" steel clips deflected when tightening the nut
2. It felt stable laterally but wiggled fore and aft--makes sense, with only a 2 inch base for a 6 inch tall tower.
For problem #1, I welded a 1/8 x 1/2" piece of steel to reinforce the plate. It took 4-5 hours to weld, clean up and drill a hole. Things just take longer. Maybe they'd have happened faster if I'd written a list of actions instead of relying on a puddle of consciousness. Later, I concluded that laying a few beads of weld might have sufficed.
For problem #2, I placed a piece of cardboard edgewise to the roof where I wanted a front rack, drawing a line to match the roof line and made a custom plywood base for each end that would expand the fore and aft dimension of the base to 8 inches.
April 28th 2020. I made a custom plywood base for each end of the rear rack.
 |
| The difference in slope (from front to back) between locations 1 and 2 may differ by 5 degrees, enough that a straight cut base will not have optimal contact with the roof. |
In version 2 of the rack I’d make the base in steel and attach a base plate (maybe 1/8" x 3/4" x 1.5") wherever the base touches the roof. To attach the base, I would have to either use a hinge or tack weld it on the car. Welding it on the car could be done if I took special care to properly drape the car to protect the car's finish from the heat or from weld spatter. The heat from even a tack weld could melt the paint. Conceivably I could use a large cotton tarp and put a piece of aluminum, foam or rubber inner tube under the base to protect the paint.
Next task: rout the top edges of both bases except where they touch the tower. Bolted the base to the tower. Add a rubber foot made of bike inner tube sections. The clips need to have their holes redrilled, because after adding the strips of reinforcing steel, I must have made the holes in the wrong places. Even without having bolted the clips on the rack seemed quite stable. It still bothers me that the back section sits on the painted part of the car instead of on the glass, which will never need repainting. A future task might be to cut and reweld where I want it.
Also done today: I cut a cardboard pattern for the base for the front towers. I’ll make the base of 3/4" plywood and will have a 10" length overall. I measured the angles between the front and rear contact surfaces and level--the difference was 5 degrees.
I quit at 4 p.m. to take a walk. No marathon session in the garage today. More tomorrow.
April 29, 2020
Next, extend the holes in the rear clips. Use the plasma cutter. Done
Mount the rack to the car and wiggle it around. Done. I've made something good here.
.One helpful thing about hybrid construction: screw holes slightly bigger than the thread diameters allow for some movement. One foot didn’t fully contact the roof--after loosening one screw, I improved the contact.
Cut the bases for the front
and measure the angle of tilt left to right on the roof (smartphone app Clinometer works really well for that). Cut a bevel per that measurement.
I got lucky doing this for the rear rack, but for the front, the right side turned out OK but not great. For the left side, I didn’t get the side to side bevel right and I didn’t get the angle difference between the front and back right either. After a few tries at cutting the bevel for the side to side angle, I redid the left side .
The bottom part of the cardboard pattern wasn't very accurate. I redid it in paper. I drew a straight line about an inch away from the edge of a sheet of paper and marked the midpoint
and measure the angle of tilt left to right on the roof (smartphone app Clinometer works really well for that). Cut a bevel per that measurement.
I got lucky doing this for the rear rack, but for the front, the right side turned out OK but not great. For the left side, I didn’t get the side to side bevel right and I didn’t get the angle difference between the front and back right either. After a few tries at cutting the bevel for the side to side angle, I redid the left side .
The bottom part of the cardboard pattern wasn't very accurate. I redid it in paper. I drew a straight line about an inch away from the edge of a sheet of paper and marked the midpoint
 |
| using a protractor set at the center of the line, I marked 2.5 degrees below each side (the angle between contact lines differed by 5 degrees for my car). |
 |
| Tracing the top part of the cardboard pattern onto my new pattern |
I cut the paper pattern out and traced it on 3/4" plywood. I cut the front top and rear of the base square to the face of the wood. I cut the bottom at the right-left angle of the roof at the rack location. In my case, 12 degrees.
Bolt the bases to the towers. Attach the clips and check stability: excellent.
Buy t-nuts for rack accessories. At least four of them for one canoe accessory.
Almost bought: compression springs to keep the clips away from the towers during installation and therefore the car's roof edge, to ease tower installation. Instead, a ghetto solution, open cell foam.
May 8, 2020. I moved each tower in the rear 1.75 inches inboard. The bases will now be on the glass.
This move forced a few changes, including extending the wing that allows me to raise the clip. I've also moved the horizontal part of the clip to below the tower wing, with plans to weld a bolt, threads up. I'll have to drill a hole in the tower wing for the bolt to go through, where I can turn a lock-nut to raise or lower the clip. I worry that a bolt will work its way up over 50 or 100 miles. This will also permit adjustment of the hardware with one tool: a 1/2" wrench. I had to extend the bolt holding the clip using a coupling nut, because they just don't make a 6.5" carriage bolt. The best part of this is that I got to use the welder again, but it did delay the project finish.
May 17, 2020. For version 2.0. use of shock cord/bungee cord to raise the clip. If it works, yay. Keep it Simple.
May 19, 2020. For version 2.0. The bolt sticking out from the towers doesn't always match the holes/slots on the clips. I bent the bolts rather than extend the slot on the clips. Maybe replace part of that bolt with chain/cable plus bolt or with eye bolt plus a hook bolt.
May 21, 2020. A note on the location of the racks. The front rack is where a Tesla made rack would go. The rear rack is pretty close to where Tesla locates theirs. My design adds an inch or so to place the tops of the racks at the same height from the ground. The separation between the centers of the bases is 37.5" (95.25 cm). The glass roof has subtle marks for Tesla's locations for a separation of about 35" (88.9 cm) between front/back.
June 6.
I have a 20' canoe. The racks are 37" apart; having the canoe on cradles 37" apart would leave me to divvy up 17' past each rack. Vern said having 8-9' hanging out like that would stress the canoe, and risk damage. He said to put the canoe cradles on an 8' rail. I welded two 4' steel tubes end to end, added two mounting plates and drilled holes to match threads welded to the rack. I welded t-nuts to the end of the rails for the canoe cradles
Bolt the bases to the towers. Attach the clips and check stability: excellent.
 |
| I laid down those weld beads to add some steel to stiffen the clip. |
Buy t-nuts for rack accessories. At least four of them for one canoe accessory.
Almost bought: compression springs to keep the clips away from the towers during installation and therefore the car's roof edge, to ease tower installation. Instead, a ghetto solution, open cell foam.
May 8, 2020. I moved each tower in the rear 1.75 inches inboard. The bases will now be on the glass.
 |
| New (better) configuration for the attachment hardware |
This move forced a few changes, including extending the wing that allows me to raise the clip. I've also moved the horizontal part of the clip to below the tower wing, with plans to weld a bolt, threads up. I'll have to drill a hole in the tower wing for the bolt to go through, where I can turn a lock-nut to raise or lower the clip. I worry that a bolt will work its way up over 50 or 100 miles. This will also permit adjustment of the hardware with one tool: a 1/2" wrench. I had to extend the bolt holding the clip using a coupling nut, because they just don't make a 6.5" carriage bolt. The best part of this is that I got to use the welder again, but it did delay the project finish.
May 17, 2020. For version 2.0. use of shock cord/bungee cord to raise the clip. If it works, yay. Keep it Simple.
May 19, 2020. For version 2.0. The bolt sticking out from the towers doesn't always match the holes/slots on the clips. I bent the bolts rather than extend the slot on the clips. Maybe replace part of that bolt with chain/cable plus bolt or with eye bolt plus a hook bolt.
May 21, 2020. A note on the location of the racks. The front rack is where a Tesla made rack would go. The rear rack is pretty close to where Tesla locates theirs. My design adds an inch or so to place the tops of the racks at the same height from the ground. The separation between the centers of the bases is 37.5" (95.25 cm). The glass roof has subtle marks for Tesla's locations for a separation of about 35" (88.9 cm) between front/back.
June 6.
I have a 20' canoe. The racks are 37" apart; having the canoe on cradles 37" apart would leave me to divvy up 17' past each rack. Vern said having 8-9' hanging out like that would stress the canoe, and risk damage. He said to put the canoe cradles on an 8' rail. I welded two 4' steel tubes end to end, added two mounting plates and drilled holes to match threads welded to the rack. I welded t-nuts to the end of the rails for the canoe cradles
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