Restoration Tips

Firstly, make a visual inspection of the case. Look for:
Missing veneer, and also burn marks or liquid stains that may have gone through into the timber.
Cracked or warped timber.
Missing or broken dial escutcheon or window glass - especially curved dial windows.
Knobs missing or incorrect, cracked or broken.
Plywood de-laminating.
Missing or incorrect speaker – eg permanent magnet where original was electrodynamic, condition of cone.
is the speaker transformer primary winding OK – easily checked with an ohmmeter – should be approx. 300 to 500 ohms.
Has the cabinet been modified – eg missing legs, incorrect dial window or escutcheon.
If a bakelite or plastic case, is it broken or cracked?
Have previous repairs been done?

Is it the correct chassis for the cabinet?
Is the chassis badly rusted?
Is the dial broken or in bad condition – eg stations missing due bad transfer etc?
Any there any missing components, for example coils. Don't worry so much about missing valves.
Are the correct valves fitted? Incorrect valves may be a sign of modifications to the chassis.
Is primary power transformer OK? This is easily checked with an ohm meter. It should measure between 20 and 80 ohms.
If an expensive radio, remove chassis and have a good look under chassis for missing items or additional items added. Does it look complete?
Most under-chassis parts, with the exception of coils, are usually easily obtainable. Valves are usually easily obtainable.

Glass and plastic dials.
Bakelite knobs for some of the early sets.
Many of the plastic knobs of later sets.
Curved glass dial windows and Bakelite escutcheons. Dial windows are available for the more common sets, and some replicas are available, but many of these items are very difficult or impossible to obtain.
Replacement electrodynamic speakers and speaker re-coning.
Tapped volume control potentiometers. These are often used on Astor and AWA radios.
If the power transformer is U/S and it is not a common type, the transformer may have to be rewound.

Add up the purchase cost and the estimated restoration cost.
Compare the total to the value of a restored radio of the same type.

Firstly, decide what is the best course of action for the particular radio.
It is always desirable, if possible, to preserve the original finish of the radio cabinet.
Many early sets are more valuable if left in their original condition as long as the case is structurally sound.
Many of these early sets respond well to a good clean and a rubdown with 0000 steel wool and a widely used concoction made of equal parts of linseed oil, turps, red wine vinegar and metho.
Use a small bristle brush to get into the corners and the grooves.
Other useful products are "Rotheraine's Reviver" and "Howard's Restore-a-Finish". Both are available from Goods And Chattels at Ferny Grove in Brisbane.

Paint stripper and approx. 3.5cm paint brush. Most economical buying in a 4 litre tin.
A couple of different widths of stainless steel paint scrapers, with the corners ever so slightly rounded so they don’t dig into the timber.
Old toothbrushes and small bristle brushes for curved or complex surfaces.
0000 steel wool.
Metho for cleaning the cabinet after using stripper.
Sandpaper – 200 and 400 grit, and a flat sanding block. You can also use an orbital sander, but care is required to ensure you don’t sand through the thin veneer
Wood glue if cabinet needs repairs 8 – Shellac
Your choice of clear finish.
Black or brown paint for edges and trim.
Replacement speaker cloth material if needed
Four self-adhesive or screw-on furniture feet protectors to replace the original hammer-in round steel feet
Pieces of veneer or coloured plastic wood filler if the cabinet has missing veneer or bad dints
Appropriate clamps to clamp wooden pieces / veneer until the glue sets

Before you start any work on the cabinet, give it a good clean with a vacuum cleaner fitted with a soft bristle brush.
Re-glue any loose veneer with a professional wood glue, using a hypodermic needle if necessary to inject slightly watered down glue under loose veneer.
Do not inject too much glue as it will cause a bump under the veneer.
Also make good any loose joints etc, and replace any missing corner bracing blocks. These are often missing, but it is usually obvious where they were originally fitted.

Note that stripping is probably the most important part of cabinet restoration. A poor stripping job will result in a poor finish.
If you decide to strip, take a few photos of the cabinet with a digital camera before you start. That way, you have a record of the types of finish and paint colour used on the various parts of the cabinet.
It is far cheaper to buy stripper in the 4 litre tins.
Take the cabinet outside where the fumes can get away easily, and, using a cheap paint brush, paint the stripper on to an area of approx 1 square foot.
You can do more if it is just a flat surface, or less if stripping complex surfaces.
When applying stripper, wear special chemical resistant gloves made from Nytrol or similar material.
Don't skimp on the amount of stripper applied – a thicker coat will usually give a faster removal.
When the stripper bubbles up after a few minutes, scrape off using a good quality paint scraper, taking care not to dig it into the timber.
Depending on the type and thickness of the finish, this process may have to be repeated a few times.
After removing the final coat of stripper, use 0000 grade steel wool to clean the timber, always rubbing along the grain.
Be very careful when working around the edge of the veneer as some veneer is very thin and it is very easy to sand right through.
When stripping curved or complex shapes, use either a spatula with a curved blade, or even better, a small brush with nylon bristles or 0000 grade steel wool.
Regularly wash the brush under a fast hose to blast out all the stripped finish and old lacquer.
Take the time to completely remove all paint and lacquer from corners etc.
The dark brown paint so often used on the old cabinets is almost impossible to remove completely from the end grain of timber, but this does not matter if the timber is going to be repainted. If, however, you want to retain the natural timber colour, you may have to strip the end grain up to 10 times to remove the paint colouring as it soaks deep into the timber.
Soak a rag in metho, and give the cabinet a good wipe to remove any traces of stripper.
When the cabinet is dry, give it a sand down using either 0000 steel wool or 400 grade non clogging sand paper.
Finally, vacuum the complete cabinet using a bristle brush nozzle.

There are plenty of commercial coloured timber fillers on the market, but deciding on which colour to use for a cabinet is far from easy. What makes it difficult is that the fill material's colour looks quite different after the shellac or estapol has been applied.
If in doubt, fill a hole in a piece of scrap timber, apply the finish you want and compare the colour to the cabinet. You can also stain the fill before applying the finish to achieve the desired colour.
I use TimberMate water based wood filler and Wattyl Craftsman Traditional interior Wood Stain.
Replacing pieces of missing veneer is also very difficult to do well. I would advise that you save as many pieces of veneer from scrapped cabinets as you can, as a good collection of different colours or types of veneer makes matching a missing piece so much easier.
With a sharp trimming knife, cut the piece to fit as accurately as possible into the hole, and glue into place with a clamp using professional woodwork glue.
It may be better to cut a slightly bigger hole if you can make the cut along the grain of the veneer. This makes the join much less noticeable. When the glue is dry, fill around the edges with appropriately coloured wood filler and sand to a smooth finish.
Sheets of veneer can be purchased from Brims in Station Road, Yeerongpilly.

It helps to highlight the grain of the timber
It seals the timber so whatever you apply is easy to remove in future
It stops any possible impurities in the wood surface from affecting the finishing coats
Shellac is purchased as flakes, and must be dissolved in metho before it can be used. While the shellac can be applied with a brush, it is very easy to get runs as the shellac is so thin, and these runs set very quickly, resulting in vertical colour stains on the cabinet. The use of a pad will make the application easier. You only need to allow 15 minutes between shellac coats.

Thin the Estapol around 10-15% with the recommended thinner so that it is easier to apply and does not leave noticeable brush marks
Always stir the Estapol well before applying, but never shake the can as this introduces air bubbles which can mar the finish
If it is a cold morning, leave the can in the sun for an hour or so before stirring to thin the Estapol
Never apply Estapol on a very hot, windy day. It will dry too quickly, and you won't be able to eliminate brush marks between the different sections of the job
Allow 12 hours for the first coat to dry, then sand down lightly with 400 grade non clogging paper before vacuuming again and applying the second coat. Allow the second coat to dry for a week, and then rub the cabinet down lightly along the grain with 0000 steel wood liberally coated with a good wax polish. I use Antiquax Original Wax Polish or Briwax Original. I tend to not rub the painted areas.

If you decide to paint parts of the cabinet, many paint shops will match the original colour if you take a sample to them.
I apply the paint between steps after the first coat of Estapol has dried. This has the advantage that if you apply paint to the wrong area by mistake, it is very easy to wipe the paint from the Estapol finish. Two coats are necessary to give a complete cover over the top of the Estapol finish.

Bakelite knobs can be polished with Brasso.
Plastic dial windows can be polished with either toothpaste or Brasso.
Knob polishing can be made easy by mounting the knob on a quarter-inch shaft and using a buffer or a battery electric drill.
Never buff polish a plastic knob as the heat generated can melt the plastic.
However, if plastic or perspex is too opaque, no amount of polishing will work, and a replacement window is the only option.
Minor repairs to small holes and cracks in the speaker cone can be done with craft glue and suitable thickness grey interface material. This can be purchased from Spotlight or Lincraft, or any shop where material and sewing goods are sold.
If the inside of the timber cabinet is in a bad way, it can be repainted with a flat black paint.

Historical Wireless Society

Restoration Tips