potassium dichromate

B

barry walker

Member
I am designing a table/desk for someone in cherry for a very rustic boathouse converted to a  summer cottage.  It is a simple shaker type piece with turned legs, two drawers and a handplaned top.  I don't like real dark cherry and would prefer to give the piece that  faded fruitwood patina look.  Several years ago, I saw a cherry tool chest at Phil Lowe's shop that was treated with  potassium dichromate and it had the look I am going for.  Having no idea about the process or even where to get this stuff, I was hoping someone could help me out here.   
 
Jeff Jewitt's book "Hand Applied Finishes" has the information you're looking for in it.

Someone has a copy of the book listed on Half.com for $6.44 and the potassium dichromate is listed on eBay (1lb @ $10.00) or you can get it at Olde Mill Cabinet Shoppe.
 
Barry - be aware that the degree to which potassium dichromate will darken cherry depends greatly on the concentration of the solution and the contact time.  Also note that potassium dichromate is a carcinogen and is toxic.  That doesn't mean "don't use it", just be aware that skin contact is to be avoided.

There are, by the way, a heck of a lot of ways to color cherry besides dyes and stains - most of these treatments do darken the wood.  One of the more prevalent methods in the late part of the 19th and early part of the 20th century was the use of lye.
 
Also, be aware that it will fade fairly quickly when exposed to bright light.  I know it will with mahoagany, and I assume it will with cherry.

Kirk
 
Barry,

Kirk said he has noticed fading with dichromate but I think he's thinking of potassium permanganate. In 30+ years of making furniture I've never had any problems with potassium dichromate fading, on mahogany or cherry, even when the piece was placed in direct sun light. permanganate on the other hand fades rapidly in sun light and slower in indoor light but it still fades.

As was said before, the stuff is pretty lethal so be careful. I've also had pretty good luck with lye but it has it's dangers as well. I'd test your preferred method out on some scrap and see which you like best. Let us know what you do and how it turns out.
 
Barry, thanks for that.  I too had the impression that dichromate was less likely to fade.

I have a question for you.  Are you familiar with Waterlox?  I ask, because I am considering using it in a multi-step finish using dichromate.  Shellac is primary finish, but use of the waterlox is to "pop" the figure of the wood.  It is a high solid oil type finish similar to danish oil.

Any thoughts?

Thanks,

Ken
 
Hi Barry,
I use potassium dichromate to darken woods and have been since the early 1980's. Yes, it's supposed to be unhealthy, but back in the day I used to get so much of it on my hands I would wash them in bleach to get the color off. I am 51 today and am in excellent health.
Formulae: Mix a liberal teaspoon in a quart sized mason jar, cap and swirl. Apply with a spray bottle for larger areas and a brush for areas that can be covered fairly quickly. P. D'ate will burn quickly and overlap lines will show if you try to cover a large area with a brush. Immediately after liberally cover the material, blot the excess off with brown paper or builders felt. I stand big pieces on the floor when I spray to let the excess run off then blot afterward.
If you are french polishing the piece apply a second shot at half dilution due to the tendency of the very surface of the wood to be removed during the first phase of this finish, lightening the color. It should be kept in mind that different trees will react differently to P. d'ate so be certain not to mix and match. With mahogany it is enough to match woods of different densities. P. d'ate will fade if put in direct sunlight over a long period of time but it is not particularly susceptible to this.
I have quite a good store of this in my shop so if you would like give me your address and I'd be happy to send some along. A teaspoon is enough to treat a large cabinet like a highboy or secretary with some to spare.
Fran
 
You guys have been a great help.  Due to my hometown's municipal budget crisis, I have been a bit less focused on period furniture lately.  Needing a little feedback on a project plan was a great way to touch base with the Society again.  I even got a call from one fellow who is trying to rejuvenate the New England Chapter.  Hopefully I can make it to the Mid-year Conference this summer and see some of you in person.  Thanks again,  Barry Walker  
 
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