Restoring silvered dials

Discussion in 'Reverse Glass and Dial Painting' started by Mike Phelan, Dec 28, 2009.

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  1. Mike Phelan

    Mike Phelan Registered User

    Dec 17, 2003
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    There seem to be many folk that think that this has to be done professionally for some reason; it might be a different kettle of fish when you are repairing clocks for a living, but if you are just hobbyist, the cost of farming things out makes little sense to me as these clocks will typically only cost £50 at the most.

    I have posted this method before, but still see questions about it. Moderators; worth a sticky for the thread?
    I am talking about the sort of dials seen on Napoleons and many German wall clocks.
    These are easily restored, as you will see, and require no special tools or other equipment at all. A few hours work maybe.

    The start:
    A German chiming wall clock that needed a complete restoration; I’ll start another thread in a month or three when I’ve done the rest of it.
    The dial silvering was badly tarnished and scratched by the hands, and there were a few dings in it. First thing to do was to photograph it, of course, and measure the diameter of the chapter ring.

    Restoring the dial:
    Obviously all the printed parts had to be removed, and the dial needed a bit of gentle panel-beating to flatten the dings.
    This dial has a raised swage around the numerals, unlike the flat Napoleon dials, so a bit more work to do later.
    I clamped the outside edge on a disc of MDF and spun it up in the wood lathe (it was slightly too big for the Myford 3.5”. Successive finer wet & dry gave me a fine circular grain, and it was finished with metal polish.
    Next job was to wash it with IPA to remove all traces of polish and other things. At this point, don’t touch the front with anything!

    Silvering:
    This is what scares people; think about it, though. When were the first silvered clock parts made, and when did we discover electricity?
    Right.
    Silvering powder is available from material dealers, but can be made; plenty of information in many clock books.
    The basic idea is to combine a silver salt with a reducing agent, and apply a dampened rag to the dial, rubbing until you see metallic silver appearing.
    A final wash with some cream of tartar (probably from your kitchen!) will brighten it up.

    Numerals:
    Because it was not a flat dial, the entire minute ring and numerals could not be done in one go.
    A member here kindly showed me a picture of a similar dial with the same font, so I used that, as it was much better than the original picture. Converted it to a BMP file.
    If you think about it, you only actually need 1, 2, 3, 4, 5, 6, 7, 8 and 0.
    With MS Paint, I edited out the hour hand and restored the zero.
    I find it’s then easier to turn the image to negative and make the numerals a different colour from white; this makes it easier to remove scratches and spots on the background, which were then white.
    The next thing is to painstakingly edit the edges pixel-by-by pixel until it all looks perfect
    That done, a change to just two colours and swap back to a white background. These were then printed on to transfer film – I use craftycomputerpapers here, but I’m sure other countries will have such things.

    Minute ring:
    I did not bother using the photo here; because of the swage on the dial, I couldn’t apply the complete ring, but split it into quarters.
    I drew it on white paper with a drawing pen, and used that. Also printed on transfer film x 4. All these have to be lacquered first.

    Final job:
    Soaked the ring, and applied it using the radius as before. Let that dry, and applied the numerals. Four coats of lacquer, new keyhole grommets and this is what we end up with.
    Not perfect, maybe, but a darn sight better than it was!
     

    Attached Files:

  2. Thyme

    Thyme Registered Users

    Sep 18, 2006
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    #2 Thyme, Feb 10, 2010
    Last edited: Feb 10, 2010
    Since I did a dial re-silvering for a member and also described here the process in detail at the time, it might be of value as a reference:

    This is from my gustav becker swinger clock ,the numbers are there and in good shape but the rest of the dial the color faded and wear off. I want a honest anwser to restore or just leave it alone. Or to restore it and have a place that restore's them do it but not coming back looking like a fake or new clock. Out of all my clock's this is the worst dial I have seen on a becker. It looks like someone cleaned it with the wrong stuff.thanks guy's!
    Attached Thumbnails [​IMG]





    When I saw this dial my first impression was that it was a painted dial. Upon closer examination, I could see that it was silvered. Unlike most dials (mostly American) I have seen/worked on, this dial is not brass. It's made of thin copper, and it's extremely badly tarnished. This oxidation is probably due to benign neglect, not from any cleaning attempts. It's unlikely that there was any form of sealant (no lacquer) applied to it when it was produced. Since it was in a moist atmosphere, once the silver began to oxidize it simply worsened until the point where the copper was also oxidized, showing as blackened tarnish. (The very rim just outside the time track apparently was under the frame; it kept that area protected enough that it's the only part where the original silver could be seen, unscathed. It appeared so white that at first I thought it was white paint!) The back of it was a real mess too, probably due to grime/crud from the movement, but that is removable.

    Here's a photo of the beginning of cleaning around the numerals. The silver comes off with the tarnish, but that's expected. The biggest difficulty is the time track: there is no effective way to clean the 60 tiny spaces in it. I am very conservative about such details and reluctant to disturb it. Unlike numerals which are relatively easy to retouch with paint, a time track once lost and retouched can look decent, but never look as accurate as the original, which was a stencil over the silver. In this case I am leaving the track as undisturbed as possible, and attempt re-silvering once I clean the entire central area. This may result in some tarnish (darkness) remaining in the track itself.


    The re-silvering was successful. After two applications I took these photos to show how it looks. As you can see, the time track is only very slightly darker in spots. Fortunately that feature won’t require any extra attention.

    The numerals have some paint wear, as is inevitable by the cleaning and re-silvering process. The paint loss makes them appear faded. There are also some scratches in the dial caused by misaligned hands, which are more visible in the numerals than in the re-silvered dial.
    (He decided against retouching the numerals, since they are acceptable as they are.)

    This clock may be lovely, but it was not of high quality manufacture. They apparently didn’t lacquer the dial originally, so there is no point in adding lacquer that was not original to it. As the final step I sealed it with an acrylic UV coating, which is invisible, to keep it from the tarnish reoccurring.

    IMHO, the restoration was optimal, considering its condition before restoration. If anyone has dial restoration needs, please PM me.;)

    To read the entire thread click HERE.



    Attached Thumbnails [​IMG] [​IMG] [​IMG] [​IMG]
     
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