Restoration

Restoration

The following are proven tips to help with the restoration of old radios. (These tips are primarily intended for the novice - Older collecting friends please make allowances for these simple rules. Naturally everyone has his own way of doing things based on his own experiences.

1. Basic cleaning

The simplest way is with some warm water and a mild detergent. In addition one can use a little degreasing agent. Because most radios that one acquires have a coating of fat, cigarette smoke tar or other residual deposit. Take care not to drench the radio otherwise there could be nasty consequences.

2. Stickers and label

Often one finds radios with labels, stickers or transfers on the cabinet, particularly if the radio has been in the hands of young people. Lamp oil to a tried and proven means of removing these. Lamp oil is a substitute for petrol and a pariffinated hydrocarbon. The remnants of transfers and stickers will dissolve and the surface whether wood or plastic will not be damaged. Always try out the solvent on an inconspicuous spot on the cabinet first. The lamp oil will evaporate and will not leave any nasty residue. One can also use modern plastic cleaners. But use with caution.

Plastic cabinets

Here Ambratec is a tried and proven cleaner. This cleaner is used in the auto workshops for the cleaning of plastic surfaces inside cars. In this way nicotine, dust etc can be removed from surfaces. It is also available under the name Key Clean (in music shops) here it is used for the cleaning of keyboards. It smells and has the same characteristics as the product made by the company Ambratec.

3. Knobs

Plastic knobs are best washed in hot water and detergent using a toothbrush. The metal inserts can be well cleaned with Sidol or other metal polish and some fine steel wool 000 grade. You could also use an Ultrasonic cleaner, which gives excellent results.

4. Dials

Attention CautionDial glasses are the most delicate parts of a radio. The quality of the printing on the glass is variable and in their aging characteristics. Some 1930's dial glasses can be washed easily without danger as the printing is firmly attached to the glass. On the other hand there are dial glasses from the early 1950s where this is not the case. With these one cannot even brush them clean without some of the letters coming off or smearing. One can in some cases seal the back of the glass with clear cellulose lacquer. Broken dial glasses, which still have all the lettering, can be scanned and screen-printed. This is a job for the expert. There are a variety of methods. (With some Lowe Opta radios of 50s I can help with dial glasses).

5. Cleaning brass sections

There are many possible methods here. An organic method is to rub the surfaces with some freshly squeezed lemon juice with a little salt added. Alternatively one can use a dessertspoon of acetic acid with a teaspoon of salt dissolved in half a litre of hot water. Using this solution one can remove the surface corrosion but you might benefit here by the use of some fine steel wool. After this treatment rinse with some fresh water. Other cleaning agents include Sidol (an ammonia based cleaner) for copper and silvered parts, which can be applied with fine 000 steel wool. One can use cellulose lacquer on the trim but be very careful not to get this on the polished surfaces of the radio - it will attack the polish. So exercise caution.

6. French Polish

This is shellac dissolved in methylated spirits. It produces a high gloss finish and can be found on some prewar radios. However there are different varieties from dark or red/brown for the restoration of mahogany tinted cabinets to the milky white color for lighter colored cabinets. French polishing is however a highly skilled method. The secret is to work slowly and build up several layers of polish over several days to let the high sheen develop.

7. Lacquered Finishes


Over the years many different surfaces were used for radio cabinets. From the fine wood veneers and French polish of the prewar years to the paper veneers and acrylic lacquers of the 1960s. Restoration should always use the original finish. For the silky matte surfaces of the postwar sets there are wax lacquers available. There are many different colors available, which can also be mixed to produce the correct tint. The old surface should be carefully sanded off and the correct color achieved by a stain. Then the wax lacquer can be applied with a fine paintbrush. If you have matched the color well then after drying one cannot detect the difference from the original finish. Finally one can finish the cabinet off with an antique wax. Be sure to let one coat of lacquer dry thoroughly before applying another. With the highly polished surfaces or more modern radios there is no ready-made solution. With these the polish is very high gloss and hard and easily splintered. In many cases the only solution is a thorough stripping and respraying. This is a specialized job requiring a spray gun and a dust free environment. One can employ the services of a professional.

8. Bakelite cabinets


These dark Bakelite cabinets can be polished up with a commercial auto polish. For fiddly bits use a toothbrush. One should use several attempts with this polish in order to break down the dull surface and bring it up to a bright sheen.

9. Speaker grill cloth.

Here we find a whole variety of conditions - from the completely ruined to the salvageable. Some materials are quite durable and only need cleaning with a soft brush. In other cases you can carefully remove the material and wash it gently. Some materials are so badly damaged that they must be replaced. This can be difficult as the old materials were specially woven and it can be almost impossible to find a similar pattern today. So it might be better to just leave the old material in place. You might be able to cannibalize from other radios. Newer materials with ugly water stains can be washed. Ask your wife for some help with sewing flaws in the speaker cloth.


10. Ponal. PVA Glue

Synthetic cold wood glues such as Ponal are extremely popular in the repair of wooden cabinets. They are simple to use and they dry quickly and with a clear finish. Restorers are however uneasy about using this type of glue with rare and valuable sets as there is no long-term experience with its use. This type of glue is not soluble once it has dries and can make a later more authentic restoration more difficult. With more valuable items therefore it is better to rely on the traditional glues. Ponal is particularly useful for small repairs or for use under lifting veneer. Here one can dilute it with a few drops of water and using a fine syringe one can squirt the glue into the even the finest of cracks.

11. Woodworm

Woodworm is the most feared pest of wooden objects. It can attack items that have spent prolonged periods on bare ground or in sheds. The main thing here is that the woodworm pest must be completely eliminated from the item. Fresh holes are always clean and bright whereas old ones are dark or black. There are chemical treatments on the market, which the DIY person can use. The liquid is either injected into the holes or else applied directly to the surface of the item. The item should then be sealed in a large plastic bag for approximately 14 days. This sealing increases the effectiveness of the treatment. The treated holes should be filled with commercial wood filler.

12. Felt feet

Often because of space limitations collectors must stack their radios. Here the use of felt feet can prevent scratches. In some cases the original felt disks have hardened or fallen off and some postwar sets never had them. You can find these useful aids in hardware stores.

13. Scratches

Depending on the size and depth of the scratch, there are several methods you can use for their removal. Very fine scratches can be polished out with furniture polish, but be careful not to polish to strongly or you will end up with a bright mark which stands out from the rest of the surface. Deeper scratches should be filled with a wax repair agent. These can be found in do it your self stores in many different colors. After filling you can apply wax or shellac to the surface. Sometimes larger scratches cannot be totally removed but their appearance can be much improved.

14. Dents

Small dents in unlacquered surfaces can be fixed by swelling the wood fibres. This can be done by dripping hot water onto the affected part. If this is not sufficient then one can apply steam. Apply a wet cloth to the area and then apply the hot end of a soldering iron. After this the area can be smoothed out with fine sand paper. One can proceed similarly with finished surfaces except that less moisture will be necessary.

15. Blisters and bubbling

Small or large blisters are an unpleasant problem but can be repaired. If the bubble has already been broken, then the cavity under it will be dirty. This dirt will have to be scraped out with a scalpel. Next some wood glue must be inserted into the blister. Then place a damp cloth on the area and apply a warm iron. As soon as the glue and veneer begin to soften, press down with the iron. Remove the cloth, weight the area down and allow to dry and cool.

16. Cabinet backs

If the radio has spent the last decade in not completely dry conditions, the cabinet back will be more or less buckled and twisted. These backs are made of pasteboard and can be flattened out again. Moisten the back and clamp between two pieces of firm timber approximately 30 x50 cm. Leave it thus for several weeks. If the pieces of timber are well sealed the evaporating moisture cannot be drawn into them or distort them. The moisture must evaporate into the air slowly. In this way the back will be made smooth again. Apply a wax polish and it will appear like new again.

17.Useful aids

Apart from the usual DIY tools such as screwdriver, pliers, hammers, files, cutting blades etc you should have some other more specialised tools such as a small compressor. This is more effective for the removal of dust than a vacuum cleaner. Also you can use a small spray gun with it. You will also need a variety of grades of sand paper and steel wool. Also a selection of clamps. Also some old toothbrushes, a syringe for injecting glue into crevices etc. A careful inspection of hardware stores will reveal a selection of lacquers, strippers and stains that you can use.

I have had a contribution on the topic of restoration from Harald Bergens, Cologne. In the course of restoring Saba Freiburg Automatic tuning radios I had problems withthegold plated strips around the press buttons. Because of age (almost 50 years) these have in most cases worn away or been heavily scratched. Attempts to renew the gold plating failed. Also spraying with gold effect spray was not a success the effect looking worse than before. After all these attempts I arrived at the following idea.First clean the strips with 000 steel wool to remove all traces of gold. After that polish the whole thing with Sidol metal polish. When they are gleaming again spray using a fine airbrush with clear lacquer (yellow birch sap lacquer).After this treatment spray over with high gloss clear lacquer.After my first attempt I was pleased with the success of the process. It looked really like gold plating.

I hope my idea might be useful to other restorers.

Best wishes from Cologne.

Harald

 
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