Do oak/cedar react with copper as with iron?

No, but the oak can change the copper...

David Barnett - SW Florida

>...to a warm grey tone, especially if left in close contact in the sun over several days or weeks. This method has been used to age replica ancient copper and bronze coins, although it would likely be combined with other toning process*. One can also see such grey patination on various naval brasses and gunmetal along oak contact areas. While toning is desirable on certain coins, it can be avoided by applying various coatings.

If natural copper patination (non-grey) is desired, such film coatings can be applied on oak contact areas alone. One very fine and surprisingly durable overall coating is polycrystalline wax. Renaissance Wax is the best known of these and is what I recommend. I would use this over patinated copper, as well. If you desire a beautiful velvety warm brown patination, clean your copper thoroughly, then hand apply the thinnest layer of peanut oil possible to your hardware, then heat it with a torch or gas burner until it begins to smoke. Bring to even shade and air cool. Then wax with soft cloth. As for cedar, I have no direct experience but would expect less toning to occur as oak was always specified for this process.

http://rg.ancients.info/guide/toning.html

Maybe, maybe even likely......

bill tindall

>My book on the subject says that copper sulfate colors some woods jet black and others grey. On oak it seemed to brown it some. Haven't tried cedar but I will try it for you and report results-western cedar or eastern red?

As it happens I have been treating wood with all manner of things to see what colors result. So far I fail to see the utility of the popular chromate treatment, expecially given its potential toxicity problems.

Permanganate, however, results in a beautiful browns, expecially on ash. I find ash hard to stain with pigment stains but this permanganate brown is so nice.

Re: No, but the oak can change the copper...

Dave Mount

>Jeez Dave, you are the Shell answer man this morning. . .

The oak shouldn't be an issue; it is the decking that is white oak, so "drippings" from the copper balusters will fall onto the oak (which is coated with Sikkens DEK finish), but there won't be any direct contact. The cedar will contact the balusters top and bottom, though the holes will be coated ahead of time with Sikkens as well.

Thanks also for the tip on retaining the brown color; I actually prefer that to the verdegris, although with 400 balusters to treat, I'm not sure I have the patience.

Dave

Re: Western red

Dave Mount

>That's a generous offer Bill, thanks. Are you treating with zero valent metal filings or copper salt solutions?

When I posted the question I was thinking of the black oak/iron reaction which, if I remember right, was iron ions reacting with the tannin in the heartwood (or lignins, I always forget). After reading the coin toning reference Dave Barnett posted I am less sure of the mechanism for an oak/copper reaction.

I'm kind of surprised I didn't Google this up -- I tried "oak copper stain" and "oak copper reaction", and the same two with cedar, and got nothing.

Thanks again,

Dave

Results of experiment

bill tindall

>Western cedar (both heartwood and sap) and white oak (heart) were treated with a dilute solution of copper sulfate. (I have plenty on hand as it cures foot rot, in the sheep, not the wife). After a few minutes of soaking the excess liquid was removed with a paper towel and the wood dried with the hair dryer. What little stubble I have dries on its own, but I find this heat source handy in the shop.

The oak browned a bit and the cedar less so. When exposed to the elements, as well as chemicals in the wood, I would expect copper metal to be less soluble than iron metal. This speculation, together with the mild coloring from soluble copper, would lead me to conclude that you won't have a problem with staining from copper pipe.

Re: Thanks Bill!

Dave Mount

>That was generous of you to do the legwork for me. Copper pipe's on sale this week, off I go!

Thanks.

Dave