Chess Set Restoration - Repairing Cracks in Ebony

IpswichMatt

For about twelve months now, it has been my life-long dream to be a chess set restorer.

Now and again people post on these and other forums asking how best to fill cracks in ebony - I know this because I've googled this question myself - and the best answer I've seen was on a guitar restoration forum, where a poster outlined how he used ebony dust and superglue to fix cracks in the ebony fretboard of guitars. So using his words as a basis, I thought I'd share with you my attempt to carry out such a repair on an ebony chess piece.

I have bought a number of sets over the past couple of years, with the intention of restoring them once I have the sufficient skills to do so. Most of my sets have a problem with cracks in the ebony pieces, and one of my sets - a set usually described as "probably an Ayres", and having a 4 inch King - suffers very badly in this regard.
This is a nice set, very good quality, but these sets are nothing like as valuable as comparable Jaques sets and I was therefore less nervous about messing about with it.

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IpswichMatt

Note that apart from this cracking, this set is in remarkably good condition - there are no chips to any of the pieces apart from the collar of one Black pawn. But the cracking is quite bad, so much so that one of the pawns has broken into three pieces, and is only held together by the baize:

 

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IpswichMatt

I thought this would be a good piece to start with - since I can hardly make this piece
any worse than it is now.

The first step was to glue the three piece back together. For this I used medium viscosity
superglue (CA glue) - I think it was Alan Dewey who recommended using medium viscosiy.  I did not make any attempt to fill the cracks with the glue at this stage - I simply concentrated on getting a good covering of glue in the centre of the piece so that the repair would be sound.

 

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IpswichMatt

Next I pushed some ebony dust into the cracks. There are 3 vertical cracks and one horizontal crack that runs along the top of the vertical cracks. The vertical cracks are much deeper, in fact they go right back to the lead weight. I used a knife blade to work the dust into these vertical cracks, but I did not attempt to completely fill the crack at this stage. I then put a drop or two of low (I only use medium for glueing the parts together) viscosity superglue into the cracks - the glue runs everywhere, covering all surfaces by capilliary action. It combines with the ebony dust to form a solid black structure.
Excessive superglue runs can be cleaned off with acetone, even after the glue has dried.

 

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IpswichMatt

Once dry, I repeated this until I had not only filled the cracks, but got the ebony dust/superglue mixture standing proud of all cracks:

 

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IpswichMatt

It might look at this point as if I've made a sticky mess, but nothing could be further from the truth - I've actually made a rock hard mess. Later I discovered that instead of piling on the ebony dust and adding a drop a superglue that I could instead apply some superglue to a scrap piece of wood and then add ebony dust to that, and the mixture remains workable for a few seconds, long enough to apply it to the piece. This allows for more accurate application.

Next I sanded back any superglue/dust mixture that was standing proud. I used 280 grit paper for this - you could use a coarser grade, I just used what was lying on my desk. You need to be careful and patient with this though, you don't want to make any flat spots and you need to be careful to avoid taking off too much. It was for this reason that I hand sanded, rather than using the dremel,and examined the results every few strokes.

 

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cgrau
Fascinating. Where did you get ebony dust? Coincidentally, 14 of my ebony Probably Ayres pieces cracked this winter.
IpswichMatt

Eagle eyed viewers looking at the above pic will have noticed that there are some recesses, especially around the horizontal crack. So I applied some more ebony/superglue:

 

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IpswichMatt

And sanded again, still with 280 grit. I repeated this until there were no recesses or"shiny bits" - where the original shiny finish remains - any shiny bits within the sanded area indicate that there is still some superglue/dust mixture standing proud (right next to the shiny bit), preventing the sand paper from reaching it.

Next I sanded with 400, 600 and finally 1200 grit. There's nothing magic about these numbers, I just used what I had lying around. I believe the sanding technique is important though - you want to find a technique that avoids leaving any flat spots.

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IpswichMatt

Next I used the polishing wheel on the dremel with some buffing compound I saw on a you tube video:

https://www.youtube.com/watch?v=VF17-um3ITk

These are Australian-made products so as you'd expect there's some bragging on the packaging happy.png but these product seem to work extremely well. Here is the final result - I am very pleased with it:

 

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IpswichMatt
cgrau wrote:
Fascinating. Where did you get ebony dust? Coincidentally, 14 of my ebony Probably Ayres pieces cracked this winter.

Hi Chuck. I had some small blocks of ebony that I bought on eBay, and I cut some thin slices from one of these with a dremel. I caught much of the dust as I did so. I wanted the thin slices for the fatter cracks, which I thought might make a better repair then just ebony dust.

If there is sufficient interest I will post pics of that repair too, but I'm still working on it.

I also have a small ebony pawn that is not part of any set, I put a gash in that and tried the ebony dust and superglue thing before I did anything to any pieces that I cared about 

Audioq

Great post! 😊 I have used a similar technique on boxwood pieces. The trick is not to panic when you see the sticky/rock hard mess. Despite what it looks like it will be great when you sand down and polish. The first time I did it I tried to be too neat and didn't get the repair proud of the surface so it never looked completely right (very neat but still with a definite crack although filled in). Does the premix glue and dust work I thought I tried that and the mixture dried too quickly to be able to work into the cracks and the matchstick I used kept sticking to the piece! Nice work and something we all can do at home. I presume you made the dust from an old unuseable ebony piece? 

IpswichMatt
Audioq wrote:

Great post! 😊 I have used a similar technique on boxwood pieces. The trick is not to panic when you see the sticky/rock hard mess. Despite what it looks like it will be great when you sand down and polish. The first time I did it I tried to be too neat and didn't get the repair proud of the surface so it never looked completely right (very neat but still with a definite crack although filled in). Does the premix glue and dust work I thought I tried that and the mixture dried too quickly to be able to work into the cracks and the matchstick I used kept sticking to the piece! Nice work and something we all can do at home. I presume you made the dust from an old unuseable ebony piece? 

Hi, I found the higher the concentration of ebony dust the faster it sets. I think in most cases you need to dump the dust on the piece first and then add glue, contrary to what I said above. Especially for filling the cracks. But for filling very tiny holes you can get away with mixing it first then apply with a pencil.

How did you match the colour of boxwood? Does boxwood  sawdust and superglue match the colour well?

Audioq
IpswichMatt wrote:
Hi, I found the higher the concentration of ebony dust the faster it sets. I think in most cases you need to dump the dust on the piece first and then add glue, contrary to what I said above. Especially for filling the cracks. But for filling very tiny holes you can get away with mixing it first then apply with a pencil. How did you match the colour of boxwood? Does boxwood  sawdust and superglue match the colour well?

I used European boxwood from some old draughts/checkers pieces. The addition of the superglue did turn the dust a bit darker but after sanding down it wasn't that much different. A barely visible lime where the crack was. The hardest bit was matching the sanded down boxwood to the aged boxwood on the rest of the piece. I ended up having to use a very weak solution of Liberon concentrated wood dyes. It took forever to get a reasonable match but I didn't have any aqua fortis to give it a dirty wash. 

MySeTH

Thank you for this post, very interesting, and instructive...(i wish i never need to do this)

IpswichMatt

Yes it would be a shame if your 1849 repro set developed cracks! I'm sure it won't

MySeTH
IpswichMatt wrote:

Yes it would be a shame if your 1849 repro set developed cracks! I'm sure it won't

i was thinking about few of my antiques chess set from 1760/1850/1910 ...

magictwanger

 Terrific job! Thanks for a wonderful and informative thread.-happy.png

liml
This is very informative. Thanks for sharing Matt.
RussBell

Excellent and instructive post!

Beginner question(s):

What causes the ebony to crack in the first place?  Excessively high or low humidity/moisture?  Or excessive temperature extremes - heat/cold?   All of these will result in expansion/contraction of wood.  But what do you consider to be the primary mechanism(s) that causes the cracking of the chess pieces?

Is super glue really the best type of glue to use?  I'm thinking of not only the fact that it dries extremely quickly which makes it difficult to work with, but also once dry it is very hard, which (it seems to me) would make it unable to expand and contract to the same degree and rate as the (porous) wood to which it is adhered, thus increasing the chances of separating/cracking developing over time at the glue-wood interface.  For example, might it be that Elmer's Wood Glue would be a better choice, since it's formulated to be used with wood?

I live very close to the Taylor Guitars factory in California.  I may stop by (or call them) and speak to their factory repair shop techs about using super glue vs other glues on ebony guitar frets....