# Black oak - how?



## vluminator (23 May 2008)

Hello!

My very first posting on this forum. Have browsed old topics over the past days and have found lots of great advice and tips - thank you!

I was hoping someone could give some solid advice on how to turn new oak countertops into something very dark grey or even black and yet keep them usable as kitchen countertops (bearing in mind they will be in contact with food, get wet etc. 

The kitchen cabinet fronts are natural birch so I want the tops to be a strong contrast. I suspect traditional oil treatment won't do the job.

I am not dead set on oak as a material but it seems to be good choice for countertops in general.


M. Karlsson


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## Tusses (23 May 2008)

Granite


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## vluminator (23 May 2008)

Tusses":2w44c1ut said:


> Granite



Eh.. no thanks.


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## Tusses (23 May 2008)

sorry - couldn't resist !

theres is black ...

and there is food safe black - thats where I shut up !

like for instance - using a walnut oil finish ... its non toxic - but no good to anyone with a nut allergy !


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## Jake (23 May 2008)

The trad way of doing it is to get some iron dissolved in some vinegar, or another acid, (wire wool is a quick way) and then brushing the oak with the solution after its been left for a week or two. The iron/tannic acid reaction creates a blackish stain. I've played around with this (and zinc, which is supposed to end up with a silvery finish, but I've never succeeded in replicating that) and it works pretty well, but I've never got a finish where I've thought 'wow'. I was just experimenting/messing around, and went a totally different direction, so I probably just didn't perfect the technique. I have a feeling (unsubstantiated) that if I had pursued it, I'd have ended with a combination of the iron thing, and black stains/dyes to get a more dramatic layered depth of colour.


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## Sgian Dubh (26 May 2008)

vluminator":3j553uyf said:


> I was hoping someone could give some solid advice on how to turn new oak countertops into something very dark grey or even black



Jake gave you one method which relies upon iron, tannin in the wood and water to create the darkening.

That's similar to the method I use that, in my experience, is more reliable than his suggestion. I use green copperas, aka ferrous sulphate. It's a green powder available from finish suppliers and chemical lab suppliers. Start by mixing about a heaped teaspoon in a pint of water. Adjust the strength after you've done a test for colour on offcuts of your wood. 

Raise the grain of your wood first with warm water applied over the surface. Let it dry and sand all the rough fibres. Apply the stain, keep the surface wet and after about fifteen or 20 minutes or so you can go over the whole surface with a dry cloth if needed to mop any remaining puddles. 

The final colour does depend to a large extent on the wood underneath, so if you have different tannin levels in each board you'll get different darkening. This may, or may not be a problem to you. In the example below I expected some variation in the colour board to board and accepted that characteristic as a positive one. If I'd wanted a more even colour I'd have used a stronger ferrous sulphate mix, but then the result would have been darker than I was aiming for. An alternative to achieve a more even result would have been much closer matching of the grain pattern, and/or ensuring all the boards came from one tree with a similarly consistent grain pattern, eg, all truly tangentially cut, or all true quarter sawn with none of the figured, rift or turnip cut in evidence. 

After the stain is dry you can go ahead and polish. Below is an example of green copperas on oak. The open pores of the wood are filled with contrasting green filler between a sealing coat of polish and and final polish coats.

In your case you'd need to finish the work surface with a high quality inerior varnish, either water based or oil based. Exposed edges around sinks and so on would best be finished with an epoxy sealer. Personally I've never been a fan of solid wood worktops. I've never seen one over two years old that didn't look tatty, unless it was purely decorative and unused, but I don't get the point of a worktop that isn't used, ha, ha.

Green copperas incidentally is what's used to turn maple and sycamore into what's called harewood or greywood. Slainte.


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## Jake (26 May 2008)

Sgian Dubh":39jwe6d0 said:


> in my experience... more reliable than his suggestion. I use green copperas, aka ferrous sulphate. It's a green powder available from finish suppliers and chemical lab suppliers. Start by mixing about a heaped teaspoon in a pint of water. Adjust the strength after you've done a test for colour on offcuts of your wood.



I guess someone else found the 'trad suggestion' lacking as well, then! It seemed a bit 'surface'/transparent to me, even the experiments which added some assistance from some added tannic acid.



> Green copperas incidentally is what's used to turn maple and sycamore into what's called harewood or greywood. Slainte.



Interesting,I didn't know that.




[/quote]

I guess it's a personal thing - but that is extraordinary - and 'minging'!


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## Sgian Dubh (26 May 2008)

Jake":lwt9t9sw said:


> I guess it's a personal thing - but that is extraordinary - and 'minging'!



Ha, ha. I'm glad you liked it. The customer liked it even better-- they coughed up hard money to take it home and eat off it. 

But seriously, filling the grain of ring porous woods with contrasting colours can be very striking and also very effective. It really changes the character of the wood. Slainte.


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## houtslager (27 May 2008)

hence LIMED OAK was very popular in the 17th and 18th centuries and again in the last 20 years.

I have also done a "limed finish " on beech , ash and elm.

hs sweating in east friesland, trying to finish a 18th sofa table :?


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## Harbo (27 May 2008)

I was at a Woodworking show a couple of years ago where somebody was selling timber in various hues including pink!! :shock: 
They injected the living tree with dyes a few weeks before they cut it down.
The dyes had been carried into the wood giving it the colour injected.
Did not really appeal to me though - I like wood to look like wood and pink - ugh!! 

Rod


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## big soft moose (27 May 2008)

vluminator":2imcrhyl said:


> Hello!
> 
> My very first posting on this forum. Have browsed old topics over the past days and have found lots of great advice and tips - thank you!
> 
> ...



I generally use a solution of ferrous sulphate to darken oak - however this isnt ideal for a food safe worktop. (though i suppose it could be sealed under a clear varnish or similar)

I'd tend to suggest either a stain or a dark wax - although getting the consistent colour will be your biggest challenge with that method.


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