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Blacklab

Black Slate Renovation?

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I am currently fixing up an old slate cased Ansonia for a friend. Originally owned by his Gran, it stopped working in the dim & distant past & has been used as a door stop ever since etc. etc. After cleaning and tickling the movement is all happy again and keeping (surprisingly) good time. The case however was in a right state and is slowly cleaning up, but will need blacking & re-waxing. After lengthy research I have found Marblack or Curator slate blacking, which is the preferred of the 2? Also can anyone recommend a decent wax polish? Or is there a better way of doing this? Your thoughts will be gratefully received.

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I am currently fixing up an old slate cased Ansonia for a friend. Originally owned by his Gran, it stopped working in the dim & distant past & has been used as a door stop ever since etc. etc. After cleaning and tickling the movement is all happy again and keeping (surprisingly) good time. The case however was in a right state and is slowly cleaning up, but will need blacking & re-waxing. After lengthy research I have found Marblack or Curator slate blacking, which is the preferred of the 2? Also can anyone recommend a decent wax polish? Or is there a better way of doing this? Your thoughts will be gratefully received.

I have used both + others but have never been happy with the results.

I found the best results was a good slow build up of shine using spit & polish with a good quality black shoe polish followed by one a coating of microcrystalline Wax.

If the slate has inlays then scrub gentley with warm soapy water (Avoiding the edges because the adhesive loosens) and get into the inlays with a tooth brush & dry. Then with a fine brush fill the inlays with "Liberian Gilt varnish" wipe away any over spills & leave to dry for a day or two then polish with the above method.

The purists will hate my method but for me it works every time. See below a comprehensive way which I use some of the methods suggested.

 

 

Marble Case Restoration.pdf

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Clockboy has hit the nail on the head with this one.

For what it's worth here is my two penneth.

The reason the black slate goes horrible is oxidization. The only one I know of is the Curator which isn't that good. Black boot polish supposed to help, but if your thinking of a finish so it looks like new the only way of doing that is to take the whole case to pieces than you'll need a proper polishing mop and different grades of paper and mops, it's a very timely filthy process and I wouldn't recommend it.

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Thanks for the advice all. I am currently experimenting with floor oil (no sniggering at the back!), yes I know it sounds a bit daft but it seems to be working. I have used this in the past on a fire hearth made from the same stuff which had a rather pronounced white acid burn (don't ask) and this worked very well. I believe (but cant be certain) that the oil is a mix of tung & boiled linseed oils.

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The problem you might have is these slate clocks are not really slate but are normally made of Belgian calcite which is very porous. The oil could just soak way too quickly leaving the pigment on top that will wipe away. 

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The problem you might have is these slate clocks are not really slate but are normally made of Belgian calcite which is very porous. The oil could just soak way too quickly leaving the pigment on top that will wipe away. 

Correct. but he says the clock is an Ansonia which is American so it might not be Belgian calcite.

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There does seem to be some debate elsewhere regarding the 'slate' used on American clocks. The oil does soak in and with the hearth I found about 3 applications appeared to correct the problem of staining. I have in the course of my day job re-oiled various materials, the great thing with oil it dries to leave a low sheen even finish and is very good at hiding stains & marks.

Edited by Blacklab

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Just a quick update. The clock originally looked like this after cleaning off the years of accumulated grime:

post-80-0-44572800-1444254426_thumb.jpg

 

After a fair bit of trial and error I used the following:

3 coats Liberon Ebony Spirit Woodstain,

2 coats Slate Oil,

1 coat Renaissance micro-crystalline wax (thanks for the tip CB),

2 coats Painters Touch Acrylic Gold paint (from Homebase) to detail, put on liberally with brush & scraped back with razor blade between coats.

a final 2 coats Renaissance micro-crystalline wax.

 

and this is what it look like now:

post-80-0-68250300-1444255054_thumb.jpg

 

My initial trials with oil worked well at first but the pale patchy areas came back to haunt me after a couple of days. Tried Priorys Black Slate Renovator without success. The spirit woodstain has worked well, its not perfect but acceptable. Some surface corrosion is noticeable at certain light angles & as Oldhippy rightly states the only way to get rid of this would be to pull it apart, grind & polish. The pale patchy areas are now well masked. The Slate Oil appears to be none other than boiled linseed oil & was slower to dry than the original Floor Oil, If I did one again I would use Floor Oil.

Edited by Blacklab

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Good result Blacklab. The issue for me is that the slate is incredibly absorbent so what ever is used is just soaks in too quickly & leaves the pigment in the surface. & leaves patches. However  before I use my boot polish method I will try your method next time. 

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Thanks for the kind words all.

 

Regarding the wood dye - there appear to be 3 main types, the old school turps/ white spirit based, water based & methylated spirit based (the one I used). I would have preferred to use the turps type as it probably would soak in more slowly, but was unable to find any. The Priory Slate Renovator was water based and didn't work well.

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As an aside, if some of the problem was oxidation, you may be able to neutralize the effects of the oxidation with h2o2 more commonly known as hydrogen peroxide which is both cheap and available from most pharmacy stores. It is mostly used to clean ear piercings and cuts etc as it is a mild form of bleach.

 

I use a 3 to 6% solution of h2o2 regularly in my stamp collecting hobby to harmlessly reverse the effects of oxidation which on early British line engraved stamps was mostly the result of many people back then burning coal or the effects of the big stink in London, it does a particularly good job of two penny blue and penny red stamps, penny blacks are not as affected by oxidation from hydrogen disulphide so less likely to need treating.

 

Info HERE on hydrogen peroxide.

 

It should probably at the very least neutralize the effects of oxidation and stop it from worsening if not remove some or all of the staining from the slate. Slate is porous by nature so it may need time to soak in.

 

Hope that helps.

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As an aside, if some of the problem was oxidation, you may be able to neutralize the effects of the oxidation with h2o2 more commonly known as hydrogen peroxide which is both cheap and available from most pharmacy stores. It is mostly used to clean ear piercings and cuts etc as it is a mild form of bleach.

 

I use a 3 to 6% solution of h2o2 regularly in my stamp collecting hobby to harmlessly reverse the effects of oxidation which on early British line engraved stamps was mostly the result of many people back then burning coal or the effects of the big stink in London, it does a particularly good job of two penny blue and penny red stamps, penny blacks are not as affected by oxidation from hydrogen disulphide so less likely to need treating.

 

Info HERE on hydrogen peroxide.

 

It should probably at the very least neutralize the effects of oxidation and stop it from worsening if not remove some or all of the staining from the slate. Slate is porous by nature so it may need time to soak in.

 

Hope that helps.

I'm also a stamp collector I specialise in Victorian stamps and I can tell you what you have done to your stamps has made them worthless.

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I'm also a stamp collector I specialise in Victorian stamps and I can tell you what you have done to your stamps has made them worthless.

 

@oldhippy Hi, it is always nice to meet other QV specialists.

 

You are entitled to your opinion of course, but on this we will have to disagree and below are some of the reasons why.

 

This is a little off topic admittedly so apologies in advance to anyone that is not interested in philately.

 

It has long been and is still common practice among many experts to remove the effects of oxidation from *line engraved stamps* as printed by Perkins, Bacon & Petch with h2o2, it has never rendered them worthless, quite the opposite in fact as it will often restore their true color which adds eye appeal which in turn makes them more saleable. If you have a lot of line engraved material in your collection, the chances are that some of them will have been similarly treated in the past and you would never even know, maybe even some of the ones you prize for their post office fresh color have been previously bathed in h2o2.

 

I have clean RPSL & BPA certificates for several stamps that have been similarly treated and the expert committee didn't seem to believe them to be *worthless* as you put it, when they were examined and issued a good certificate.

 

I also have almost unlimited access to many QV experts via a stamp group that have authored specialist books on QV stamps, sit on expert committees or are consulted by committees, some are even chemists by trade that recommend or take no issue with the practice of giving line engraved stamps a bath in h2o2. I can put you in touch with many eminent QV experts via a QV specialist stamp group if you wish, there is more assembled QV knowledge in one place than you can ever access via any book or SG specialist catalog, in fact the group has been responsible for many additions or corrections to SG Spec etc. So if you are a specialist QV collector as you state then maybe you might both enjoy and benefit from becoming a member of that group.

 

It also has sub groups for plating of stamps. The focus is mostly on QV line engraved stamps, however surface printed stamps are not off topic, just less popular with many of the members there. Many of the major GB QV specialist dealers are also members of the group and use it as a resource to check the plating of some of their stamps or to get opinions from those more specialist than them on QV postal rates to various destinations or the likely authenticity of various material. It is a great resource for information on perforations and cancellations such as distinctive Maltese Crosses, post office numbers, scarcity of cancellations or earliest known uses of various 1d red plates on cover with many databases and studies shared including a study on 1d reds printed from black plate 9 with numbers in Maltese crosses which showed up in numbers in 1843 suggesting either the plate being put back to press or some old stock being supplied to post offices. Lots of fascinating stuff there, so please do feel free to private message me if you are not already a member and have any interest in becoming a member.

 

If you are a member of the GBPS, a lot of contributors to the newsletter and GB Journal also come from that group, as does the past editor of it.

 

You can find info on page 8 of this GBPS newsletter about hydrogen peroxide treatment of stamps where it also states that an ex chairman of the RPSL expert committee was of the opinion that there was nothing wrong with the use of h2o2 on stamps. Here is another article on the American Philatelic Society site about hydrogen peroxide treatment of stamps, the relevant part being at the bottom of the article. Obviously I would never give stamps with fugitive or double fugitive inks a bath in any form of liquid as the colors would run and it would ruin the stamps and I have never treated other surface printed material, however *line engraved stamps* I have no problem at all with treating if I observe the results of sulphurette on them. h2o2 over time becomes reduced to just hydrogen and water which also makes it enviromentally friendly.

 

Here is an earlier 1840 2d Blue without white lines added that was also suffering a little when I first acquired it but now looks like this.

 

post-1462-0-14083100-1444398078.jpg

 

Below is an example of an 1841 2d blue stamp that is obviously affected by oxidation.

 

post-1462-0-26152000-1444396800.jpg

 

Below is a stamp that looked similar to the above before treatment with h2o2 and is now in my opinion looking better for the treatment. I will let others be the judge of that though. If the 2 stamps were listed for sale on ebay for example or a dealer site, I know for sure which would end up with the largest price tag.

 

 

OK, back to the topic of slate clocks ... Very nice restoration job on that clock by the way, it looks great now!

 

Best Wishes

post-1462-0-73680200-1444396912.jpg

Edited by mk3

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Hi Black Lab,

What an amazing job. I am going to give this a try on one of my clock's. You mentioned that next time you would use a floor oil, may I ask what brand? I went to my local home depot and they sold me boiled linseed oil,will this work? They had never heard of slate oil. I would love to get your feedback before I start my project. Thanks for your time.

Laura

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Thanks Laura & a warm welcome to the forum.

 

I suspect boiled linseed is the same as slate oil in as much as it smells the same (not particularly scientific I know). There are many wood finishing oils out there, being mixtures of linseed, tung and other nut oils. The best thing to do is to try a small area on the back and see what happens after a few days. I had a few go's with mine before getting it right. Please note that these 'oils' don't stay wet, but will dry & harden after a few days, not to the extent of a varnish but remain supple & easily removable. As for the floor oil, I installed an pre finished soilid oak floor in my living room about 4 years ago and gave it a few coats of Woca maintenance oil, it still looks as good as new.

 

Please post pics of the project before & after.

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Excellent job BL, I can't believe how "like new" the clock looks like now and the great gold enhancements...and all by hand! Very nice and tidy job!

 

@Laura: Welcome from me too and I hope you enjoy our place here!

 

Cheers,

 

Bob

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Philip, slate cleaned and stained & oiled first, then engraving overfilled with acrylic gold paint, surplus paint carefully scraped back with razor blade then waxed. Hope this helps.

Edited by Blacklab

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Hi all,

I don't like Marblack etc..it's leaves a horrible carbon layer on the slate if put on to thickly, which does polish off when waxed..M&P used to make a slate blacking the best ever oil based. .As usual they stopped making it..Only way really is to rub down with wet and dry paper finishing off with the finest. As there is nothing else suitable, the Marblack should be used sparingly and rubbed off..Then as mentioned good old Black Boot Polish Kiwi, not the pound shop rubbish. build it up using the makeup remover (dry small round wipes) nicked from her indoors..5 or 6 thin coats is usually enough, let it dry and soak in for a good few hours next day ok, and then using the wipes slightly damp with a small bit of polish on shine it up in circular motions, it will come up a treat.. Here is one I did earlier.. if links are allowed.. 

Len

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