I’ve mounted the first heat shield on my black Mirage. To allow quick access to the engine compartment, I decided to use Dzus quarter-turn fasteners to secure the aluminum panel to the chassis tubes. These have been around for a long time but someone may never have installed them so I'll elaborate a bit.
I bought them from Speedway motors but they are available from other sources. Be aware that the same items vary in price over about a 2-to-1 range from different vendors. Since my panel is thin (0.040” 6061-T6) the springs needed were the “raised” ones, thicker panels need the “standard” height springs. Mounting the fasteners is not hard—simply weld the steel tab onto the chassis, pop rivet the spring in place, and place the Dzus button onto a 13/32” hole in the panel. In reality it isn’t quite so easy; the tabs must be mounted so they are oriented properly or the panel will be bowed in or out. Also, locating the holes in just the right place on the panel so they align with the mounting tab holes is a pain but a transfer punch will make the job easier.
I prefer Avex pop rivets for things like this; they are 1/8” diameter and have a large grip range.
I considered a number of methods to cut the heat shield panel to the proper shape. Since I was concerned about not distorting the cut edges, I tried my “El Cheapo” Harbor Freight plasma cutter on aluminum for the first time. It cut the sheet very well with no distortion. Just a little dressing of the edges to make them smooth was all that was required. This is a case where a template is definitely needed—cutting cardboard and throwing away mistakes is far cheaper than scrapping aluminum!
The next step, after I finish the left side heat shield is to go over the surfaces with an orbital sander to remove the stain & discoloration on the aluminum, treating it with a phosphoric acid solution, rinsing, drying, and then giving it a coat of zinc chromate primer.
