How to Prevent Hairline Cracks in Chessmen

• Winter: 35%-45% relative humidity (RH)
• Summer: 55%-65% relative humidity (RH)

1. Store chessmen in a wood coffer.
   Storing chessmen in a tight fitting wood coffer reduces the exchange of air inside/outside the coffer and is probably the single most important step in managing humidity levels. 
2. Purchase Art Sorb silica beads. 
   Art Sorb silica beads are commonly used by museums to maintain proper humidity levels in displays. The beads automatically add/remove moisture from air according to the targeted RH level. In my case, 50% RH is the nominal humidity level and provides a buffer between the minimum/maximum RH levels recommended by the House of Staunton (above). Art Sorb beads are available from a variety of vendors including these: Gaylord Archival, University Products, and Artsorb Online.
3. Purchase a humidor tube. 
   I needed a container with holes large enough to allow humidity exchange, but small enough to contain the beads (i.e., so they didn't spill into the coffer). Humidor vendors sell a variety of such containers and I found the Heartfelt HT 4 60 tube a perfect fit for my application. Note that the humidor tube came with 60% RH silica beads which I discarded as I prefer to use beads that are closer to the nominal humidity levels referenced above (i.e., 50% RH).
4. Store the filled humidor tube inside the coffer.
   After purchasing the silica beads and humidor tube, pour the beads into the tube, close both ends of the tube tightly, and store the tube inside the chess coffer. To see what this looks like in practice, refer to the image below. 
5. Purchase a humidity sensor and display unit.
   Using a sensor and display unit (such as this package available from Amazon) makes it easy to confirm the steps above are effectively controlling the humidity level inside the coffer. 

Thanks for this !! I have some hairlines in my Kasparov  v. Kramnik Chavet set I don't  want to get any larger.

Super helpful! Thank you for posting this information, Bertilak. 

and if you want more tips...I'm sure there are many tips on guitar forums!

 That seems like a nice product,but you also have to be careful about adding humidity as well.I have an acoustic guitar collection and I always keep my humidity in the approx. 50% range in that room(portable floor humidity unit(available anywhere).I keep my chess sets there as well.....Keeping sets out all year,on a table etc,can definitely cause problems in the long run,as there are swings in humidity all the time.Acoustic guitar players know this well and it applies to any wooden product that you care about.

I'm not convinced that Ebony is so easily problematic though.The finest guitars use Ebony for the fret boards and bridges and Martin Guitar has used this wood for over a century......It's usually how well we keep the particular wood,which in this case is Chess related products.....Also,it's totally possible to never have an issue,but being careful(which is quite easy)is no big deal....Just a little common sense and a small effort.....Best to all.

Magictwanger I agree that adding humidity is something to consider. Most times the equipment described above does an excellent job of maintaining the target RH level. However, in the depths of winter when the air inside our house can get really dry, I occasionally (maybe once every two weeks) insert a damp sponge into the coffer to add a small amount of moisture and to help recharge the silica beads. This step is probably not necessary, but if I see the humidity level drop below 50%, I try to be proactive and act before the RH gets too far from nominal. The nice thing about using a coffer is that only a small amount of air needs to be maintained at the optimum level as opposed to the entire room or house.

We do use a whole house humidifier connected to our heating system in winter. Unfortunately, there is a limit to how much moisture it can add (especially when it's really cold and the heating system is running constantly). Additionally, I have found that I have to be careful to not overdue it as I inadvertently caused some minor mold/mildew issues inside the house one winter!

This is precise and valuable information indeed. However, I have also seen Jacques sets sold with some chipping but no hairline cracks whatsoever. I don't know whether that's the rule rather than the exception but it does beg the question: what made these sets so resistant in some cases? I think the culprit is nearly always improper drying of the wood and/or too heavy weights in the pieces. In which case you can humidify or dehumidify all you want, but you will be fighting an uphill battle. It's sad to see that the demand for chess pieces and other wood products is such that improperly dried wood is often used.

Maik1998 there is no doubt that  improperly cured wood can be a serious problem as it relates to hairline cracks. I believe this is why vendors such as the House of Staunton offer a 1 year warranty for cracks (as it takes at least a year to determine if there were any wood curing issues).

On the other hand, I know that humidity can definitely play a big role in hairline cracks as well.  

For example, I gave my father (who lives in super dry Arizona) a used 10 year old ebony and boxwood chess set that I had owned for about a year with no issues (I had inspected each piece very carefully with a strong light and magnifying glass, so I know the set was in great condition). Despite my suggestion that he take the steps detailed above to maintain the proper humidity levels, he neglected to do so. When I visited him a year later, several of the pieces had developed hairline cracks. When I visited again this past year, the cracks had become even larger.

 Btw,there is a similar and "complete" system that guitarists put in their cases.No need to buy the silica and tubes separately(though that is a very good system advised here by Bertilak).....It's called a Humidipak and can be found at any guitar retailer.....Keeps humidity at 45-55% when placed inside any type of box/case.....I don't use it because i use a portable humidifier in my room,but if I were to go away for a long while,it would be fabulous,as the method Bertilak mentions....Moral of story,as told by a highly respected guitar builder/wood expert......."Wood wants to crack and it's not easy to keep it from happening at some point".

Best regards.....Mark

Thanks Magictwanger! I had no idea the Humidipack existed.

It sounds like it could be a cost effective - not to mention convenient - alternative! I suspect this discussion thread will be valuable to folks searching for answers on this topic.

The  lack of detailed information on how to effectively manage humidity levels baffles me - especially considering the large number of relatively expensive chess sets availble. 

With the proper precautions, I do *not* accept that hairline cracks are inevitable and that folks should refrain from purchasing ebony or blood rosewood chessmen.

Bert....I think you should be congratulated for bringing this up,as most folks don't have a clue as to how important correct humidity is to "both" wood and "health"!!.....The Humidipaks are pricey,but easy to use(like a snap).....They go for $29 for two packets,enclosed......I think(since i don't use them)they come with refills or something like that,to add value.....but....From the fellow guitarists who I know and who have very fine wooden instruments,"those folks" place two packets into the guitar case and I'm told the product works great.If you have quite a few acoustics,like me,it gets pricey.One reason i have a good in-room humidifier that i closely monitor....Best regards,Mark

Just inspected my HoS blood rosewood set, and one of the rooks has cracked

Will the hairline cracks get bigger and bigger until the piece splits, or are these cracks more of an aesthetic concern?

they're mostly just an aesthetic concern (and in fact, a crack caused by drying wood can almost disappear if the humidity goes back up)

i must admit that those Boveda packets look great....makes the Humidipak product seem pricey! I just ordered the 58% Boveda packets for my 10 CB sets that I bought over the last few months....I kinda' went overboard,but am thrilled that these Boveda packets exist and are so cheap.....Thanks for the mention.

I know this is an old thread but the issue is still current. I have two nice sets from HOS that are in the coffers. I have two questions. 1)  The coffers come with nice foam pieces with green material on both sides that can be used as spacers and buffers between the trays. Will keeping a bunch of this foam inside the coffers hold in moisture and eventually get “musty” or moldy ?  2) I put a moisture monitor in the cabinet where the coffers are kept in a closet and it reads between 62 and 66 per cent. Is this too high? The closet does not have a central heating inlet so it stays cooler than adjacent room 

I collect acoustic guitars, so I know about wood/humidity.66%,long term, is a bit too high.

Bought a Boxwood and Rosewood set from chessbazaar in June.  5 Pieces are creacked in less than 3 months. 

Yeah, I emailed them 10 days ago when my first rosewood rook cracked. and they said no problem we will send a new one.  

Now 4 more pieces both boxwood and rosewood!  

could you post a picture of the damage please?