Saturday, June 14, 2014

Nickel plating

Next to re-covering a leathercloth case, nickel plating was a new activity to gain experience on.

Older machines mostly don't have chrome, but nickel plating for the shiny parts. (Chrome plating became viable industrially I believe around '26.) Some of the fittings and screws of the 101 were a bit rusty, some of the screws more than a bit.  To bring back some shine to these parts also, they were re-plated.

Several sites on the internet describe how to do electroplating and shops offer for sale solutions or kits to do nickel plating. From some online hints on plating, however decided to do electroplating entirely with regular home and kitchen ingredients. These rusted fittings for the carrying handle ('pakawa') were badly pitted, but even then were improved by the process. (Chemical de-rusting would perhaps have been better.)

This electrolyte was mixed from kitchen ingredients; vinegar, salt and sugar. For nickel an old coin was found, a battery for the electricity.

Measure what is the smallest amount of liquid that can be used to fill the chosen container. The smallest amount that enables the parts to be submerged to be plated. In this case a plastic take-away container with a lid was used. A lid is good to have, to be able to close the electro-plating bath for storage.

Using the kitchen scale, find out how much volume (weight) this was. For every milliliter of vinegar, add a tenth of that in salt and in sugar. So e.g. 200 ml (or 200 gram) of vinegar, add 20 grams of salt and 20 grams of sugar. (Use powdered sugar for easy dissolving.)

It helps to have heated the vinegar a bit to around 50 degree C, the salt and sugar dissolves easier then.

Regular vinegar, without any 'taste' elements if possible. You only want the acidity and no complex molecules or organic stuff in there to complicate the reactions in the mixture. The salt helps making it conductive to electricity, plain kitchen salt (NaCl).

But then the sugar. Why add sugar. Did some head-scratching with a chemistry colleague about why sugar would be good to include, but it probably makes sense. The sugar does not electrolyze, does not take part in the reactions. The sugar does however go into solution, so adds to the saturation of the electrolyte. This means that less of the nickel-salts need to be put into the solution before the plating at the cathode starts. It makes the plating channel more efficient.

So far, the mixture is still safe; it probably tastes very bad, but is not unhealthy as such. Note that as soon as you start plating with the electrodes in the mixture, you are creating chemical waste. This will contain metal salts and will need to be disposed of safely through the chemical waste disposal route of the local municipality. This is another reason to use the smallest amount of electrolyte that will do the job.

For the electricity, used a battery. A voltage of between 3 and 5 volts should be fine on this scale. Also tried a 9V battery, but that was too much. Too high a current (battery overheats due to internal resistance) and too rough a plating (porous).

Using alligator clips, the coin is attached to the '+' of the battery and a to-be-plated part to the '-' of the battery. For the nickel-supplying electrode an old coin was used. Actual nickel coins are not as common as they were, but this old 'gulden' is actually made almost completely of nickel. Of course the coin (or other nickel metal part you use) will partly dissolve and not survive.

It's a good idea to do this in a well ventilated area. Not only because of the chemical waste being created in the electro-plating bath (unhealthy stuff), also because hydrogen and oxygen will be created at the electrodes.

As soon as the electric circuit is closed, bubbles appear at the electrodes and soon a green haze will form around the positive electrode. That is the nickel salts in the solution. First the electrolyte mixture needs to be sufficiently filled with nickel salts for these to reach the negative electrode, but then the nickel is deposited on the to be plated parts. With a saturated mixture, it now takes between 10 seconds and a minute to properly nickel-plate a small part. Move around or stir (wooden spoon) a bit to get all surfaces treated. Being able to put a lid on it, the whole electro-lating setup can be put away for a couple of days in between use. Having it all on a tray made sense, as well as some tissue to dry and clean the parts as they come out of the bath.

Probably obvious to the experts in this field, but brass or copper parts are really best for plating. The parts do need to be completely clean. That means that also new, brass screws need to be polished to remove 'patina' and any remaining oil or grease from the manufacturing process. Brasso and a soft cloth. Brass rings, the left two already nickel-plated.

One of the newly nickel plated rings mounted in the new, replacement record storage tray in the lid.

Having now seen the difference between plain steel and copper (brass) for plating, perhaps a first step of copper plating a part makes sense. For the next project perhaps.

Some screws will probably get a second treatment, but this carrying handle will stay put for a while and will just have to do. (Taking that off requires pretty much a complete disassembly of the whole machine.)

It does look the part though, very flashy deluxe late twenties machine :)

Friday, June 6, 2014


With the #2 Portable on the shelf, am back to the current hobby restoration project that is proving an exercise in new techniques (for me). Re-covering a wooden case in leathercloth, for one.

Like the carrying cases for older typewriters, portable gramophone cases of the twenties and thirties are generally made of wood and covered in a leathercloth. This covering goes by various names, I've heard 'Leatherette' a lot as well as 'Rexine'; both I think the trade-names of manufacturers of such cloth. Usually made of a fabric backing with a (nitrocellulose?) covering in a pressed pattern. Modern variants also made with PU or PVC even.

This current restoration project turned out to be in a worse condition than first expected. The leathercloth often can be revived with leathercare products, but in this case the structure had become brittle and hard. Probably it was lacquered at some time to 'freeze' water damage, unfortunately it looks like the lacquer chemically attacked the Rexine.

No amount of polishing would recover this. So the whole machine was taken apart for the case to be stripped for re-covering in a new leathercloth. It really helped to read about somebody else re-covering a case on his blog/site (thank you very much!). Got some good pointers and advice there, made it seem achievable.

Before ripping off the old covering however, new leathercloth needed to be found to re-cover the case.

This machine's case was covered using blue Rexine (being a British made machine) and quite amazingly this is still available. The original manufacturer that supplied this in the 1920-ies went out of business in 2005, but the product is still being made and sold by Ratchfords in the UK. They are quite happy to sell a meter and ship it out, the blue however was not in stock (and making 500 meters to special order really would have been too much).

The local bookbinder however stocks lots of book covering materials and amazingly even had a roll of genuine Rexine in a suitable shade of blue. So even though this is just a shade deeper blue than the original, it is genuine Rexine for re-covering the case. (For typewriter cases, a length of more common black leathercloth should be easier to find.)

Didn't take pictures of the basic wooden box (and the storage box with all the loose parts), but it is a plain wooden box with softboard ('essex board') top and bottom. The old covering came off without too much effort, the old glue having become brittle and hard. With a light sanding and smoothing, the case is ready for re-covering.

Using the old leathercloth patches as template, new sheets of Rexine were cut slightly oversize. Used wood glue (PVA) diluted with a bit of water and a drop of washing-up liquid and applied with a paintbrush on the case. Dilute only lightly, make it a bit runny but definitely more like glue than water.

The case originally had lining and panels, pressed into the leathercloth. To make lining (the Remington #2 case also has such lining I noticed), made shallow grooves with a file along a steel ruler in the surface. When applying the new Rexine and pressing it down, pressing the cloth into the groove will make a neat line. (Using a screwdriver tip or fingernail, the Rexine seems to soften from the glue and is 'malleable'.)

In the same way the thick lines of the top panels were scribed into the softboard and the leathercloth pressed / scored into the pattern. The thin lines just scored along a steel ruler. As the glue (and cloth) hardens the lining is firmly in the material.

One learning was that the corner pieces should have been fitted right after glueing the leathercloth on. With the Rexine still a bit soft, they would have been seated firmly into the case with a better fit. Another learning was to not dilute the glue too much. And keep pressing it down to prevent lifting in spots.

Re-covering a tatty typewriter case should also be very manageable, complicating factor however is that most cases have the fittings riveted on instead of using screws.

(This project by the way is rebuilding a 1928 / 1929 deluxe version of a His Master's Voice model 101 portable gramophone in blue with nickel-plated fittings.)

Tuesday, June 3, 2014

Modern business machines for writing, duplicating, recording, etc

A short film showing off all kinds of modern (for 1947) office equipment for the creation and reproduction of documents. E.g. a very impressive wide carriage Varityper, working Addressographs and much more. About 16 minutes, also hosted on the archive.

Information technology galore!