Chevy HHR Network - DIY "1/2" Panel

HHR “INFILL” PANELS

I’ve thought about this modification (making my LT a “half panel") for over a year now, but had no luck finding an “outside” window film application that might closely match my body paint. I did some research to determine how to “attach” the metal infill panels to the rear windows. I actually contacted 3M, online, and received good information from them to determine what adhesive tape to use. They asked appropriate questions ie materials/weight of metal, etc.
I also did some research/experimentation to determine the correct rubber trim to use. I actually ordered a similar rubber trim with the same profile but deeper “fit” and found it not pliable enough at the tightest corner to install without wrinkling.
I will give as complete a parts list as possible at the end of this document.
I did a base coat/clear coat paint application. I did, however, do an automotive prime coat over the pre-primed metal to insure compatibility of the paint products. Primer used was a pre-mixed product.
I am a retired sheet metal worker, and had access to getting the metal needed for this project.

PROCESS

• I used poster board cardboard sheets for the window pattern, bought in the hobby/art department of the local department store, about $.98 each. I simply taped the cardboard to the side of my HHR and rubbed/traced an imprint line of the window with the butt end of the handle of a steak knife, onto the cardboard. Then just cut out with a pair of scissors.

• For the two rear cargo windows a 25” x 16” piece of metal is required for each window. The metal used was 24 gauge “pre-primed” sheet metal, for use on outside flashings. I paid $10.00 for the metal, that price is very subjective. Lay the cardboard pattern on the metal and trace with a pencil. I cut the metal with a pair of hand snips (commonly called aviation snips) This would probably turn out better if an electric unishear was used, you could have the shop where you buy the metal do this for you if you have your pattern, but that will cost more money. The time to cut the metal by hand was less than 5 minutes each.

• I had a gallon of mixing reducer required for the base coat paint, left over from my older brother painting my ’37 Ford, so I went with a base coat product compatible with that reducer. I also had a gallon of clear coat and the required activator. I’ve done some “primer painting” over the years so painting of the infill panels was not beyond me.

• Both panels were primed on each side. I primed over the existing prime coat with an automotive primer to ensure compatibility with the finish coats. I let each side dry @ 80 degrees for 15 minutes. I moved from my painting area into my shop bathroom which I had heated for each drying period. I then did my first base coat, this was not a heavy coat and as you can see in the photos it was a bit “streaky” you can actually see the black color in the mix of my “Dark Tarnished Silver” paint. Again I allowed drying for 15 minutes @ 80 degrees between each coat. I did a second, heavier coat, no streaking now and then after drying, a third coat.

• Next, the clear coat finish. I did one light coat, letting dry as before, and then two more coats. I let dry @ 80 degrees for three days before handling. If I were to do again, I would have done another full application of clear-coat after the 3 day cure to get an even smoother/brighter finish.

• To attach the infill panels to the windows, clean the windows thoroughly and apply the trim adhesive tape as a continuous border around the perimeter of the windows. At this point I will say it would be best to have a second set of eyes and hands to apply the infill panels, I did mine by myself and got absolutely lucky on the first window, centered perfectly. The second window was off, just very slightly forward, this made applying the rubber trim much more difficult. The adhesive tape is “tenacious”, once the application of the infill panel is started, you are committed.

• Applying the rubber trim is quite simple. Pick a starting point and insert the “rear” leg of the rubber into/behind the window edge using your thumb as a backing and folding open the rubber, pushing the rubber into the gap between the glass and the car body, slightly stretching along the way. When you get to the finish point, cut the rubber being sure to NOT cut short. I actually applied a very small dab of epoxy glue to close up the very small “line” at the match point.

These panels are removable, so they do not have to be considered permanent, that was important to me, but with the adhesive quality of the trim tape, I’m sure it will distort/ruin the painted infill panels if removed. At the last pictures I show the issue with the second panel not being aligned properly and its affect on how well the rubber trim seats to the window/body opening.

Materials

• 2) 25” x 16” 24 Gauge Pre-Primed Sheet Metal

• Transtar 6084 1K Acrylic Speed Sealer (Ready to Use)

• Omni Base Coat 6223 (1 pt.)
• Omni Medium Reducer MR186 (1:1 Mix Ratio)

• U-POL System 20 Urethane Clear Coat
• U-POL System 20 Standard Hardener (4:1 Mix Ratio)

• 3M Automotive Acrylic Plus Attachment Tape (06384)

• Neoprene Rubber Edge Trim 3/16” Opening, 5/16” Depth
(From McMaster-Carr, Item #8507K214, 25 ft)