When I got it, three of the ribs over the speaker were broken. One was missing; another was broken out completely; a third was cracked. I don't have a good "before" picture, but this picture shows the case with the replacement rib being fabricated. I made the missing rib from bondo, using another rib as a mold in modeling clay. Because I could only cast the outside portion of the broken rib in the clan, it took several attempts and an awful lot of sanding to get it right. I attached the new rib with JB Weld and with a good bit of finish sanding, the replacement looks great. The other cracked ribs went together easily with super glue.
This shows all the ribs in place and some sanding that I did. I started off with 200 grit sand paper. This is far too rough for bakelite and caused deep scratches that I had to fill with primer. I would recommend starting with about 400 grit wet dry sand paper. I also recommend a good washing before sanding. I use Dow Scrubbing Bubbles and a brush. It cuts the built up crud and leaves the case in a dull sheen.
Sanded, Primed and Painted
Here it is after painting, but before wet sanding. I used Krylon Antique White. I baked the painted case at 150 degrees for a couple of hours to hardened the paint and to get it to dry faster. Standard Krylon takes an awful long time to dry on its own.
Can you identify the new rib? Its the third from the top. You really cannot tell by looking at the front. With the chassis out, however, you can see the repair from the inside.
The Dial Cover
The original dial cover had yellowed and shrunk. I therefore needed to reproduce the dial cover. I picked up a piece of scrap "line board" at Home Depot for $.51, my cheapest ever Home Depot purchase! The board, which is really tightly pressed paper fibers, was thin, so I glued two pieces together to get about a 3/8" thickness. I traced the dial opening and cut the board with a scroll saw. I then sanded it until it fit through the dial opening. I then ran the pattern through a round-over router bit on my router table and sanded a little more.
Baking the Dial Cover
With the form ready to go, I had to come up with a suitable plastic to use for the cover. I had recently purchased a TV remote control packaged in a plastic case -- you know the kind that you cannot physically open without scissors -- and used the back flat piece for my cover. I cut it slightly larger than the form and popped the form (on the back side of a baking pan) into the oven at 350 degrees. I found that this worked, but I had to hold the plastic to the form as it cooled or it wouldn't contour to the form. I also found that I not only needed to preheat the oven, but I needed to preheat the form as well. Once I did this, I was able to hold the hot plastic to the form with a smooth dish towel (don't use terry cloth) for a minute or so. Then let the thing cool and peel it off of the pan and form. If you take it off while the form and plastic are too hot, the cover will warp. This technique works pretty well and substitutes for vacuum forming.
Speaker Hole
The chassis was dirty and about one third of the speaker cone was gone. This blurry picture shows the speaker removed from the chassis. I had the option of looking for a new speaker (which wouldn't be original) or working with what I had.
Repaired and Reinstalled
This is my repair. I used a donor cone to replace the missing piece and glued it to the existing cone with fabric glue and teabag material. It is not a perfect repair because the donor was not the same size as the original, but I worked with what I had. Although not pretty, the speaker sounds fine with no rattles or other problems.
