Ebonizing is a technique used to stain timber black. Traditionally the colour is created by painting on an iron oxide solution on to the timber where it reacts with the natural tannins in the woods. The iron solution is made by adding wire wool to vinegar. Depending on the natural tannin quantity of the wood you may need to improve the reaction by first applying a solution of tannic acid to the timber (to do this a tannin “tea” is made by simmering high tannin sources – e.g oak shavings, oak leaves and galls, even teabags – in water).
Here are the results of my initial experiments. This is the result after 3 application of the tannin ‘tea’ to an off-cut of elm and shows the reaction after about 10 minutes.
The top half of the timber was painted with an iron solution made using pickling vinegar, and on the bottom half I used an iron solution based on apple cider vinegar. The apple cider reaction was much quicker (despite the wire wool only having had a couple of days to stew) which I suppose must indicate it is more acidic than the pickling vinegar (which had stewed for about 7 days).
The two paler blotches are where I did not prepare the wood with tannin solution – the lack of reaction shows that elm has a limited amount of natural tannins.
I was not really satisfied with any of the results so a bit later on I applied a second coating of the tannin solution over the stain and – while it was still wet – added some more iron solution. Things are much improved but still not the kind of deep black I hope to get. This is it after an hour:
… so I have mixed the sediment from the pickling vinegar into the more promising apple cider concoction and plan to do 4 coats of tannin on the table legs before applying the iron solution. Hopefully this will be good enough, but if not I’ll do a second coat.
this is what the legs looked like after I had applied 4 coats of tannin solution and then tannin followed by iron solution x2. The one on the right has had a quick rub with a cloth. We’ll have to see how it looks with the oil finish on, but it does look quite a deep blue/black even at this stage.
bit hard to tell with my crappy camera phone/lack of photographic abilities but following the application of a couple of layers of wax oil the legs are now jet black. Final pic of the finished table tomorrow…