Cleaning/Repairing a Slate/Marble Clock

[S.Kierkegaard]

Hello, everyone,

I am new to this forum, and look forward to have wonderful discussions with members here; I am an amateur antique timepiece collector.

Just recently I acquired a Waterbury mantle clock with a case made of black slate and grained marble. It has an exposed escapement, jewelled pallets, and looks quite stunning.

Unfortunately the clock does not run, the case has numerous small chips at the edges, and is quite dirty. The back door's hinge is also broken.

I did wipe the case with a damp cloth, but it now looks rather dull and I would like to have it shined.

Is the Weiman granite cleaner appropriate for this kind of cleaning? How can I, if possible, repair the small chips and the hinge?

Thank you for your inputs in advance.

 

[S.Kierkegaard]

Can anyone please help me on this project?

 

[Richard T.]

Hello and WELCOME to the NAWCC message board.

I did a search of the archives and found some information that may be of use to you.

https://mb.nawcc.org/showthread.php?t=5854&highlight=marble%2Fslate+repair

https://mb.nawcc.org/showthread.php?t=21329&highlight=marble/slate+repair

Above are two examples. There may be others as well.

Best,

Richard T.

 

[Bogey]

I can't help with the chips, but as for the finish on the Marble/Slate, I believe in taking the easiest approach first and that is to clean it. I've found that many of these clocks are covered with grime that takes a lot of elbow grease. Get a good quality nonabrasive all purpose cleaner and start at it. It usually takes more than just one shot.

If that doesn't work then take a look at options for polishing it. There will be others with more experience than I have in that regard. You can also do a search on polishing marble here on the board and I'm sure you will have all sorts of advice to consider.

Good luck with your new clock.

 

[S.Kierkegaard]

Thank you for your replies and your links.

I was wondering as to how one can apply epoxy resin to the chips.. Also, how do members here post pictures?

I would rather share the photos so that you can see the condition.

 

[Jeremy Woodoff]

Click the "Post Reply" button, type your text, then scroll down and click the "manage attachments" box. This will allow you to search your computer for images.

There are "slate blacking" products available from clock material suppliers, but I've not used them. Another possibility, after cleaning, is black shoe polish.

 

[S.Kierkegaard]

Okay, the first picture is the current photo of my clock, which was lovingly cleaned but is rather dull in appearance, and the second and third photos are the seller's photos showing the chips:



How can I repair chips such as the ones shown above?

Again, thank you for your inputs.

 

[barryj]

hello, you could try Black Milliput for chips in slate.

 

[SamS]

I have a slate / marble clock that I am currently working on. I used two part epoxy mixed with Carbon Black to fill a fairly large chip. I used the technique discussed elswhere on the message board for repairing porcelin dials. The process was like this:

Scotch tape over the chip, then masking tape to support the scotch tape.
Fill with the blackened two part epoxy.
File and wetsand after the epoxy is hard.
Finish case with Formby's oil finish.

This case was in very bad shape with a kind of mildew or whitish discoloration. It took significant wet sanding with 400 grit, 600 grit, and then 1000 grit to bring it back to black (was dull when finished sanding). I filled the gold areas with gold leaf paint, and then finished the entire case with the Formbys. I didn't take the time to fill every chip and make the case "perfect". The chip repair still shows, it I had gone through the process onces again, I could have filled the very small "line" that shows along the edge of the repair (patience was not there).
-> posts merged by system <-
More pictures, last ones weren't the ones I really wanted attached - not sure what happened.

 

[S.Kierkegaard]

Thank you for your comments!

To SamS: I really enjoyed seeing photos of your project (yours seems like a beautiful clock, I may add); would you apply the same method to smaller chips?

To Barryj: Would you kindly share more about your experiences with a black Milliput?

Thank you again for recommendations; I really do appreciate them.

 

[SamS]

Hello S.K.,

Yes, I actually did do this to many small chips (and cracks).

 

[Bill Ward]

S.K
Both of these clocks appear to be of rare black Belgian marble, not slate. Both are inlaid with a semi-precious stone called porphery- it's not painted "graining". Marble can be polished with abrasives to make it shine- slate needs some coating, like shellac or paint to make it shiny.
I'd start with a very good cleaning, as recommended above. Then, if you're not satisfied, you can try abrasives on a flat block, perhaps starting with 800, and going as fine as you want it shiny. Remember, we're not polishing wood here; if you want a mirror finish, you have to polish it like a mirror, with very fine abrasives, at least to 2000 mesh, perhaps to 8000. Sandpaper usually only goes to 1200, but auto-body stores sell much finer grades.
Personally, I don't like marble too shiny, as it looks plasticy. The classic finsih is with tin oxide, which is IIRC, about equivalent to a 6000 mesh. It's a lot of work too!
Of course, if you coat the marble with a plastic finish, like poyurthane varnish, it'll look like plastic.
If you repair with epoxy, as described above, make sure the surfaces are flat and square- the tape often has to backedup with something somewhat rigid, like sheet metal, or at least cardboard. Although the stone polishing has to be done first (epoxy can't be polished like stone) you'll want the shinyness of the stone to match the epoxy, so you might want to do some test patches first. As noted, the epoxy can be dulled down somewhat with steel wool
The amazing thing about this procedure is that the epoxy comes out just as smooth and shiny as the back side of the tape, even though it's applied to the rough and dull adhesive side. It must disolve away the adhesive.
But please, if you have one of these elegant and restrained Edwardian clocks, don't trash it by painting it or applying shoe polish. Let's give these faded matrons a touch of respect!

 

[barryj]

hello,black milliput is a two part epoxy putty that is soft and workable for an hour or two, slowing getting hard until 'rock hard' when it can be sanded to a very smooth surface. I don't think any repair will be invisable unless completly painted over, but the milliput does blend in, and at some angles the shine helps make things less noticable.
Milliput is also in Superfine White, and you can sculpt new 'leaves' and such like for those french type spelter cases, (if you don't mind using gold paint). I have also scultped a section, made a rubber mold and produced a casting in 'white metal' (you can melt it on an ordinary kitchen cooker).
With chips in alabaster cases I have had good results using a two part clear resin filled with alabaster shards/powder.