Aero: Rear Spoiler

First off: the swearing.

Remember the duck-bill template I originally made to trace out the contour of the trunk? Well, it turns out that 2D objects don’t act the same as 3D objects, so when we bent everything to the correct angle of the dangle to sit on the mounts, it was several different kinds of caddywompus. I had to have a bit of a re-think and start almost from scratch.

The solution was to cut the template out at with the material at the correct angle on the trunk, but I had no way of doing that consistently without a fixed datum to start from and reference, so the first thing I needed to do was affix the central lower-mount to the trunk. Which meant I needed to finish fabbing up those mounts.

If you enlarge the picture, you’ll notice that the 1/8″ holes are countersunk. This is because for the brackets to fit flush on the trunk, I need to grind down the ends of the rivets. Countersinking those holes gives the end of the rivet something to grab ahold of after the end is shaved off.



Each bracket will get a wing-head quarter turn fastener to keep things quick-release.



With that done, I got the central bracket mounted to the trunk and worked on the template from there. Once it started getting close, I had a good reference off of the template for where to mount the other 2 quick release fasteners, and finish making the template. Using clecos on the template helped ensure that every time it went on the trunk, it was in exactly the same place.



Unfortunately I ruined a large piece of ABS using the original template, leaving it too small to work for my purposes, so I had to  cut another blank out from scratch. But seeing it start to come together definitely buoyed morale.



Next, some rubber / cushioned edge trim went on to fill the air-gap and make sure no further trimming was necessary on the bottom edge.



From there, it was time to measure it for the top edge and do the final shaping. By rule, it’s allowed to be 10″ from the bodywork and not extend out past the edges of the fenders. Here I’ve already mounted the brackets for the body mount struts that support the upper edge.



The body mount struts use standard hardware sizes, but have a very nice square nut that fits the brackets to facilitate tightening everything into place without a tool on that nut. Wherever possible, however, I like to keep my metric car with metric hardware, so I made my own ‘square’ nuts using some M6 x 1mm nylock nuts and the disk sander:



As expected, and by design, the trunk still works! 2 quarter turn fasteners, and it lifts open with the spoiler still in place.



12 more holes and 15 rivets later, et voilà, job’s a good ‘un.
I may yet paint those brackets black so they blend in a bit better, but for now things are pretty darn good as is.



And of course, the money shot. I think the car is finally starting to match that license plate!


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