Authentic Finish for a Roman Workbench

black_oak2_IMG_9408

The only thing that disappoints me about my Saalburg workbench is the finish. It’s not jet black like the original I studied in Germany in June.

Of course, when the bench was thrown down a well circa 200 A.D., it probably wasn’t jet black then. But still, the black looks correct to me because I’ve been staring at photos of a black workbench for months now.

Today I figured out how to reproduce it.

I’m at Larry Barrett’s house this week taking a chairmaking class with four other friends. We’re building the Jennie Alexander Chair (with a few modifications) made famous in the book and DVD “Make a Chair From a Tree.”

Today we split out the long back posts from green oak and began by sorting through the oak stacked in Larry’s yard. Some of it looked exactly like the oak Saalburg workbench. And I do mean exact.

black_oak_IMG_9412

This oak had been stored in a giant steel tub in the side yard of Larry’s house and the steel had rusted through, releasing a continuous supply of iron into the water. The result: jet black oak that wasn’t just on the surface. The wood was jet black as much as 1/2” into the wood.

This makes complete sense. At Saalburg, The wooden objects were thrown into wells along with lots of iron objects. It made the same stew in Larry’s log tank.

I have no plans to reproduce the finish on my bench, however, but I know how to achieve it.

— Christopher Schwarz, editor, Lost Art Press
Personal site: christophermschwarz.com

About Lost Art Press

Publisher of woodworking books and videos specializing in hand tool techniques.
This entry was posted in Roman Workbenches, Uncategorized. Bookmark the permalink.

18 Responses to Authentic Finish for a Roman Workbench

  1. Richard Mahler says:

    Another method that has been around for over a century is putting your wood in a sealed chamber with ammonia – called fuming, popular in the arts and crafts period for mission furniture. I have used fumed veneer espcially for bookbinding projects and in marquetry.

  2. eeyoris21 says:

    Before I read the article the first thought I had was… the blood of a Caesar. Et tu Brosimum rubescens.

  3. MattK says:

    I used some driftwood from a lake to whittle some wands for my kids (and me…) recently and the wood was just about jet black except the surface that had the usual silvery grey of drift wood. I assumed the wood had been through a bush fire and baked and then went in the lake. Maybe it was something I hadn’t thought of? I think it was probably eucalyptus given most of the trees around the lake (in Tasmania). The blackness was full thickness but the wood was not very thick, maximum of an inch.

    • Richard Mahler says:

      Very likely that is how the wood got its blackness. I purchased a large slab of California Redwood that had been in a forest fire in the 19th c. at the latest and this tree’s trunk and roots had been under water from then until fairly recent years when it was excavated, sawn and dried. It has a very contorted grain and the color ranges from black to purple to gray. I am using it for the body of an electric guitar.

  4. Jim O'Dell says:

    I made some signs for a customer and they wanted the weathered look but I didn’t have any weathered wood. I decided to try the method of placing torn up bits of steel wool in white vinegar for 24 hours. I used one whole 0000 pad in a little less than one quart of vinegar. I shook it occasionally during the 24 hours and when I brushed it on the wood it almost instantly turned ebony black. It was beautiful. The wood was white oak and while it makes more sense now I didn’t realize it would turn so black. While not really the weathered grey look I was going for the signs turned out great and the customer was thrilled.

    • ejcampbell says:

      I used the same process to get an intentionally black oak on a medicine cabinet. I put the vinegar and steel wool in a glass jar, resting on a vegetable steamer in a pot of boiling water for a couple hours, then let it sit overnight. The steel was all used up. The acetic acid in the vinegar combines with the iron in the steel wool (a pile of steel nails works also) to produce iron acetate. This combines with tannins in the wood to turn them black. It works best on high tannin woods like oak, ash, and redwood. Low tannin woods can be helped along by applying a coat of tea first. I then fused a white grain filler on the medicine cabinet and finished it with (non-yellowing) water-based poly. Looks really cool with the reverse grain.

      • Jim O'Dell says:

        I looked up the process you’re talking about and it makes me want to build something just to do it. It’s very beautiful.

  5. Leonardo Herrera says:

    Old chemistry workbench were stained black by a combination of nasty chemicals. It was durable and nice.

  6. Bob Easton says:

    Some of us make a two part ebonizing solution using similar ingredients. Oak shavings cooked in water produce tanic acid. Steel wool dissolved in vinegar produces an iron oxide solution. Introduce both to a piece of lumber and it turns black. Very similar chemistry. …. or, just save all that cooking and dissolving and just splash white vinegar on your bench. Maybe it was the wine?

  7. “I have no plans to reproduce the finish on my bench…” Ahhh, come on!

  8. volzwgn says:

    What about the charring process you use on tool handles?

  9. Israel Katz says:

    Chem 101: Iron + water but starved of oxygen = black rust

  10. pfollansbee says:

    I remember Alexander used to have a large plywood box outside the shop, line w fiberglass so it could hold water. And filled with oak she was saving. Really dead-flat wide riven oak. Once beautiful wood. JA saved it so long, thinking if she saved it, she had it, but if she used it, it would be gone – that it got covered with the thickest, most vile, putrid coating of scum I have ever touched. At JA’s instruction, I reached in there one time to fetch a once-glorious piece of oak for a joined stool seat. “Just brush that off, it will be fine once you hew/plane it, etc.” – I almost threw up. Eventually tossed that piece of wood away, and never stored oak in stagnant water again. I learned instead to get faster at working the riven bits into boards, and/or to work riven air-dried wood. Ask Larry if that water storage tank is still outside JA’s shop…if it is, don’t go near it. You might get some on you…

  11. Looks like bog oak. Certainly the process is similar, although it seems Larry is doing it in less time than the average 3,000 year old bog oak log.

    Are you… are you making a black chair, though, Chris? If so, I can’t wait to see pictures.

  12. Gilgaron says:

    I wonder if, with red oaks famous porosity, you could pump the vinegar/steel wool derived iron acetate through the wood to get it below the surface.

    • Jeremy says:

      This is a really interesting concept, especially with the aid of a vacuum pump, I could see potential there for inky blackness permeating throughout. Using iron gall does already penetrate a fair bit beneath the surface, perhaps for similar reasons in red oak.

      Before I started burning everything, iron gall was my favorite finishing first step for red oak.

  13. Lee Pickart says:

    If you ever decide to put a finish on the Roman bench, remember to be authentic you need an area stained by spilled garum.

If you can't spot the wiener in the comments, it might be you.

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s