Don’t Sand – Burn off your Machine Marks Instead - Popular Woodworking Magazine
 In Chris Schwarz Blog, Woodworking Blogs

One of these boards was handplaned and the other was left straight off the machine.

Shou sugi ban – the Japanese finishing process that chars the outside of wood – is an ideal surface finish for some furniture pieces. One of the unsung advantages of burning the wood is that you can reduce (or even eliminate) sanding or planing your boards before finishing them.

There are limits to this, of course. If your jointer, thickness planer or saw leaves deep marks, this won’t work. But if your machines (or the machines at your lumberyard) are set up nicely, you can save yourself a lot of time.

This trick works with all woods, but it works best with softwoods, especially the yellow pines, firs and hemlocks. The pieces shown in this example are Southern yellow pine. Both pieces are cut from the same board and were next to each other before I ripped them apart. (I’m a homewrecker, I know.)

On one of the two examples, I simply left the milling marks from the jointer, planer and table saw. On the other piece I removed the machine marks with a smoothing plane.

The example on the left was handplaned. The one on the right was machined.

Then I burned both examples with a propane weed burner. This inexpensive tool attaches to a portable propane tank (I used the one from my gas grill). This tool pumps out 500,000 British thermal units (Btu). It should be illegal. I could burn down the neighborhood with it if I wanted to.

I charred each piece with the torch for identical periods. I brushed off the soot with a stiff-bristled brush. And then I took photos.

As you can see, the samples are a little different on every surface. The handplaned one looks good all around, which is to be expected. On the machined one, the surfaces that passed through my electric planer are totally acceptable. You have to put your eyes right up to the samples to see any difference.

On the sawn edges, you can still see scratches from the circular blade.

On the sawn edges, there is a little difference. You can see some scratches left from the sawblade. A sharp rip blade would remove these marks – my blade is about halfway to being replaced.

On the jointed edges, the difference is most obvious (to my eye).

The jointed edges are where you see the most difference. The rippled machine marks from a jointer are easily spotted below the char. I have found this to be a consistent result. But I can improve the final finish by slowing my feed rate over the jointer’s cutterhead.

There is, of course, an optimal way to process the stock: Run your pieces on edge through your planer. Let the planer remove both the jointer marks and the sawblade marks.

Even though the solution is a little more time-consuming, it’s still faster than sanding.

— Christopher Schwarz

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Showing 15 comments
  • McDara

    Just got back from Memphis and all of the furniture in Elvis’s jungle room is finished like that.

  • charles543

    Why should the burner be illegal? If you burn down the neighborhood, that is illegal, but there is no reason why the tool should be illegal.

    • shallnot

      See: hyperbole

      In particular hyperbole used as humourous effect.

  • John Passacantando

    Very helpful explanation of a technique I’ve wanted to try. Plus I already own the weed burner because, well, who doesn’t need a flame thrower? My question is, is the charred and then waxed finish decent for outdoor furniture? Say to make a picinic table from southern pine? Isn’t the charred finish used for external house siding?

    John

  • Yolaxochitl

    Here is a commercial sight that shows shou sugi ban being used architecturally. It also shows results with different styles of burning.

    http://charredwood.com/history-of-shou-sugi-ban-charred-wood-treatment/

  • mark_ragnar

    This process really looks great on Douglas Fir. Early this year I made a king sized bed this way. Polyurethane over the burn works great; it just takes a lot of coats to really seal it.

  • TJdaMan

    Maybe with another wood. That pine looks awful like that, like the cheapest of old crate furniture.

    • amoscalie

      I’m with you, I don’t think this something that I would do.

    • McDara

      Try that technique (just a sample to look at the effect) and then apply a bright color dye (Arti, transtint, etc) You might be surprised at the look.

  • pmac

    I kind of dig the machine marks and burn combination. The jointer marks not so much but the angle of the saw marks with the burn add a cool element. Not sure why the jointer marks bug me so much. The just look blah.

    • C. Stanley Plane

      The young kids in the maker movement seem to like the saw kerf marks. It gives their work a “bad ass” look. I’m not part of the maker community, but some day I’d like to attend a MakersFaire. I’m not sure what goes on there besides makers taking selfies with other makers, but it sure looks like fun.

  • Spoiler

    I’ve read in your past comments about the process that you simply burn, brush with wax as the final step. Have you tried other “final steps”? varnishes? sprays? etc. I understand the idea is to KISS but wondered if you have other successes.

  • John Cashman

    Those weed burners are nuts. They sound like a jet engine. In the northeast, there’s some idiot every winter who burns their house down using a weed burner to melt ice.

    They are a lot of fun though.

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