Majestic Model 5LA5 Bakelite Radio (1951)

The jury's still out on this cute little Majestic set, which I rescued for $5 at a huge estate sale of moldy junk. Have you ever seen such a thick layer of grunge? This "before" photo was taken the same day I brought the radio home. The top of the cabinet was literally green, indicating that this set served some hard time in a garage or damp basement. Worse, there's a largish chunk broken out of one side of the cabinet, near the rear (not visible in this photo).

Cosmetics

Despite its unpromising appearance, the cabinet cleaned up beautifully with warm, soapy water, revealing nary a scratch on the glossy bakelite. The speaker is mounted on the side of the chassis (facing left from a front view), which allows the louvered front to have a sleek, seamless appearance.

I still haven't tried to repair the broken cabinet. The deep louvers wrap completely around to the back, so a replacement piece will need to match that louvered pattern.

After this page had been online for a while, I received some advice on cabinet repair from a couple of visitors. Their remarks follow.

----- Original Message ----- 
From: Mike Rasmussen
Subject: Your (damaged) Majestic 5LA5 

Phil -

Was looking through your site, and saw your cry for 
help in the 5LA5 page. There's a fairly* simple way 
to fix the body, though it really may not be worth it.

Call around to local model and hobby shops (serious 
ones, not K-Bee or something like that.) Ask them 
if they have any epoxy putty. The "Kneadatite" 
that's sold by the wargaming company Games Workshop 
works best, but "Milliput" will work well, too, and 
is finer-grained. A good, serious, model shop should
have some, of some sort. While you're there, get (if 
you don't already have one) a little twist drill, 
sometimes called a "pin vise" (go figure) and a 
fair-sized bit for it. The idea is to drill small holes
in the sides of the case, along the edge of the crack,
lengthwise... IOW, drill along the length of the body,
starting at the face of the crack.

You then stick some thin wires into these holes, running
across the whole missing area, to support the epoxy. 
You might do well to make a "die" from a small piece of 
epoxy; Mix up a small piece, about as large as a shooter
marble, and form it to a rectangle about 1/4 inch thick.
Wet this very well, and press it into the louver/design 
on the same side as the crack. ALL the way in. Really mash
it in there. Remove carefully, and set aside to harden.

That's your new forming tool. Mix up a good-sized bit of
epoxy, and form it onto the wire, but make it thin-about
half as thin as the body, if possible. Let harden, and 
add another layer, up to the very top of the design. Then
use the epoxy tool to scrape the design into the epoxy 
putty before it sets. Smooth with very, very fine 
sandpaper (wetted), and let set. Neither Milliput or
Kneadatite harden with much of a shine, and Milliput is 
white, so you'd have to paint the set... But you'd have
to do that no matter what, I guess.

Hope it's helpful, but, like I said, I'm not sure it's 
worth the effort....

Mike


----- Original Message -----
From: Steve Thompson
Subject: Repairing Bakelite Cabinet 

I don't know if you've fixed your Majestic Model 5LA5 or
not, but I have a suggestion.

I build scale models, and the technology for scratch-building
components has really taken off in the past decade or so. 
Here's what you do to cast a component.

A. Make your model. Wax is one option. Sculpey is okay, 
but it tends to swell when heated, and shrink when cooled. 
However, you can sand cured Sculpey using a fine sanding 
film or paper to get a smooth finish. Just be sure it fits 
when you're done. Because you should use a rubber mold,
you don't have to worry too much about small undercuts.

B. Make your mold. The thing to use is Room-Temperature 
Vulcanizing (RTV) rubber. This is NOT the silicone stuff 
that comes in a tube at the hardware store. It is a two-part
liquid that you can also get at a plastics supply store, 
or from Micro-Mark, a source for modelmakers (Don't bother 
with the "liquid" rubber they sell. It's cheaper but doesn't
work very well). RTV is expensive -- about $28 or so, but you
get a lot of it. Follow the directions included.

Make your mold in two parts:

Put your model on the bottom of a straight-sided rectangular
enclosure just big enough to hold everything (no need to use 
more rubber than you need). I make mine out of sheet styrene,
held together with glue and rubber bands. Place it face-up 
on a pad of modeling clay, sealing any gaps so the rubber 
doesn't get underneath. Spray everything with Pam to act as 
a release agent. Pour on enough rubber to leave about a 
quarter-inch of rubber above the highest point of the model. 
Allow to cure.

Carefully remove the clay/model/rubber from the enclosure.
Having one or two sides you can remove (held by rubber bands) 
makes this easy. Remove the clay bottom and flip the mold over. 
Taking an Exacto knife with a curved blade, gently remove any 
rubber "feather" or flash from around the model, so you have 
a clean border between the mold halves. Then make a number of 
small craters in the rubber to act as "keys" for the top part
of the mold. Put it back in the enclosure, with the old bottom
facing up.

Make a couple of "sprues" from clay. These are the passages 
through which you will pour the resin. Make them about 3/8" 
around tapering toward the bottom, and attach them to the back 
of your model, which is now exposed and facing up. Two passages 
allow the air from the mold to flow out. (When you pour resin,
you will want to pour into the sprue which goes to a lower part 
of the mold. That way, the air in the mold will go out the 
other, higher opening.)

Spray with Pam again and pour your rubber. When it's cured, 
remove the model and sprues, and there's your mold!

C. Pour your casting.

There are a couple of resins you can use:

One is polyester resin. You can get this at any plastics supply 
company, and it's pretty cheap. Art supply stores and crafts 
stores sometimes carry it too, as well as a number of dyes for
coloring it. You'd probably have to experiment a bit to match 
the color. Polyester is not very strong, and sometimes it 
expands a little when cured. It's also brittle, but adding color
tends to mitigate that. The real problem I have with it is that
it's hard to pour it without getting bubbles. And it really 
stinks. And it can remain tacky after curing.

The best stuff to use is a two-part urethane from Micro-Mark 
called CR-600. This stuff is great. It has the consistency of 
water, so air bubbles are minimized. Very easy to use. It's a 
little pricy, but worth it. Use a respirator or mix and pour 
it outside.

Again, spray all surfaces with Pam (but don't overdo it). After 
pouring, you may want to tap the mold on the table top to 
encourage any bubbles to leave. Hopefully, any that remain 
will be on the bottom of the part, where they won't matter.

Once you've allowed the casting to cure, take the mold apart,
and clean up your part. Fill any pinholes with resin. The part
will sand, polish, and take paint easily.

Voila!

I hope you find this helpful, and not too confusing. The Web address for
Micro-Mark casting materials is:

http://www.micromark.com/

Good luck!

Steve Thompson

Thanks to Mike and Steve for their detailed advice. One of these days, maybe I'll get up my courage and try fixing that cabinet!

The dial lettering poses a different problem. When I took this photo, the lettering was mostly in place, except for the 0 in the number 70. By the time I got the chassis out of the cabinet, I noticed a number of extremely thin papery white things scattered on top of the chassis and inside the empty cabinet. After a moment, I realized that they were the painted lines and lettering from the back of the dial. The slight jiggling of pulling the chassis had caused the delicate paint to fall right off.

The bits of paint were much too brittle and delicate to glue back on, so now I have a dial that's missing about half of its lettering. Luckily, I still have this photo as a guide, so, in theory, I could sit down with an extremely fine brush and try to hand-paint new dial lettering.

Electronics

This radio is a pretty conventional "All-American Five" design, using 12SK7, 12SQ7, 50L6, 12SA7, and 35Z5 tubes. It has one interesting feature, however.

When I first looked under the chassis, I wondered if it had been plundered for spare parts. It had many fewer small components than most AA5 sets, yet it played just fine, so obviously nothing important was missing.

Looking closer, I noticed a small, rectangular component with seven leads coming out of its flat molded body. When I got a schematic, I learned that this is Part 10-102, the Audio Detector Unit, which incorporates eight resistors and capacitors within a single, molded unit.

I suppose this early integrated circuit was a cost-saving measure, lowering the parts count and simplifying the assembly. It looks like ceramic, suggesting that its innards should be pretty reliable.

Like all old tube radios, this one still needs routine capacitor replacement. The electronic restoration will wait until I decide what to do about the cabinet, however.

©1995-2017 Philip I. Nelson, all rights reserved