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The perforated metal needed to be very rigid in order to provide a robust, high quality shell for daily use. I decided on 18 gauge carbon steel. After reviewing several patterns, a staggered round hole pattern using
5/64" openings on 7/64" centers was chosen. This configuration provided 41% open surface area and would insure very good airflow for cooling while retaining a rigid structure.
I had to purchase far more metal than I needed for this mod so I had the manufacturer cut a few pieces to my final dimensions to avoid uneven hand cuts on my end.
In the beginning, I couldn't decide on Aluminum or plastic for the side panels. Since there is a plastics dealer, with a showroom, nearby
I determined that plastic would be fine for the initial mod (with Al to follow) and purchased a full 4' x 8' sheet of 1/4" white foam PVC. I had a few panels cut close to the final dimensions so that I could experiment if need be.
The project also required several ongoing trips to the local Home Depot, hobby shop and hardware store for miscellaneous items as needed.
Once the materials were in hand I used the previously created cardboard templates to drill the plastic side panel attachment openings and cut the front panel openings.
The first prototype was made entirely of foam PVC panels like this one.
When test fitting I found that there were some errors in the initial dimensions for the attachment holes in the cardboard side panel templates.
Panel filled with plastic auto-body filler.
Close up of repair
So the attachment holes were filled, the plastic panels sanded finished, new openings re-drilled and plastic primer applied.
New holes drilled next to repair
Nitro-stained panel prior to sanding
Sanded and primed panel repair
The side panels were then fixed in place for test fitment. Once satisfied, they were removed and painted. I experimented with Aluminum, matt Nickel and silver-frost colored paints.
The front panel was cut using the previously made template as a guide. The power panel and optical drive was installed and the panel openings tested for fitment. When the fitment was checked the panel was removed and painted.
The painted parts were reassembled to get an idea of how the finished case would look in a given color.
Once I was satisfied with the overall dimensions and look of the design, I set out to create the metal part of the shell. Initially the shell was going to be fastened to the case using 1/4" hollow brass beams and tiny head hex screws so that it could be removed if necessary.
The pre-cut perforated metal was hand formed into place over the MDD steel shell using plastic shims to give the proper dimensions (to allow for the brass beams under the shell).
Metal shell fitted into place
The final shell was formed
Now a test fitment using the hex screws was in order.The round openings in the perforated metal were too small to accommodate the screw shafts so they were drilled slightly larger where it was to be attached.
Once attached, the black hollow hex head screws looked ok but the shell was time consuming to attach and detach using this method.
After some thought I determined that small 1/4" magnets would provide the ideal properties as an attachment system for the metal shell.
Now it was time to cut out the front openings for the power button, audio jack and optical drive. I basically eyeballed the openings based on the test fitment over the steel case.
I thought that two small, separate openings for the power button and audio jack in the perforated metal would look best. However, the power button was physically attached to the mirrored drive door panel as part of Apple's original case design (Some very minor plastic surgery was required to remove it).
Attaching it to the perforated metal directly would not have resulted in clean look so I couldn't have two separate openings in the shell as I'd hoped.
In addition unless I wanted to perform additional metal work to move them, I had few options for placement as the electronics were fixed in position to the original Apple steel case. I opted for a solid aluminum power panel centered over the underlying electronics in their original location.
There were several solutions available for the optical drive bay "door". I could either make up a hinged design or attach the "door" directly to the drive tray (a la laptop drives). I opted for the latter for the sake of time (it would be much simpler and take less time to implement).
After all fitment and cuts were performed paint colors were chosen. I chose silver-frost for the metal shell and matt nickel for the side panels (The aluminum paint was too shiny for my taste and it provided a VERY uneven metallic finish - lots of over-spray).
Although the side panels were previously primed and sanded several times, the paint finish was uneven and revealed too many surface imperfections in the PVC. I spent the next few days sanding, priming and painting to no avail.
I decided that vinyl film would provide better coverage and finish for the side panels. I located some Kapco 2mm silver film and made a purchase (no local shops would sell me the film so it was made directly from Kapco). Again, I had to purchase far more material than needed for this mod.
While waiting for the film to arrive I sanded most of the paint off the side panels to insure proper adhesion. When the film arrived I measured, cut and attached a piece to the first outer panel using the wet method. Careful use of the squeegee resulted in an acceptable surface finish although not what I desired.
The inner and outer panel surfaces as well as the panel edges had to be covered using separate sheets. The trickiest parts were the edges. A long 1/4" strip of vinyl had to be precisely cut in order to provide a high quality look once the panel coverage was complete. This tried my patience a bit as I'd spent much longer on the plastic side panel construction than I'd intended.
In the end the vinyl film coverage, although good for a newbie-home-mod-using-hand-tools, was below the standards I'd initially desired.
When attached to the case, the side panels also flexed a bit more than I liked so I expoxied 1/4" hollow brass beams to the inner top and front panel surfaces with JB Weld. That stuff is killer. A magnet will actually stick to the material (it contains steel).
Now the side panels were more rigid and held their flat profile when attached to the steel case. It was time to reassemble the tower and throw it all together.
The steel case was previously blown out with compressed air to remove most of the metal shavings from cutting. Next came a wipe-down with a damp sponge and then a vacuum. It looked like all of the miniscule metal shavings etc were removed (Loose metal shavings are bad for your electronics ;-)) so the front and top of the case were given a quick coat of matte black paint.
After drying, the internals were re-assembled. I found that the double sided foam tape used by Apple to attach the cable hold-downs had degraded from the heat to it was replaced and the hold-downs re-attached.
Once the re-assembly was complete the bare assembly was fired up. It booted. Yay!
The finished metal shell and side panels were attached to complete the case mod.
Now on to Cooling mods...
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For other System or Case conversion articles, see the Systems Topics page.