advice sought: roughening beam to look like rough sawn lumber

[Doug]

Ok. So the architect called for a 26' douglas fir beam rough hewed into a shallow arch as an accent piece for our front porch. About 22" deep at the ends arching down to ~10" in the middle. About 6" across. Impossible to find in the east so we put in an LVL and I figured I'd veneer it with two by spruce all glued up to look like a one piece beam. Lots of work later, it's almost done. Problem is, it looks like veneered glued up spruce. So I bought a steel brush for my drill and I tried roughening it with the brush. Sort of works but lots of work. Then I thought, ok I'll wet it down with a concentrated brightening agent and let it sit for a while eating away at the wood - then use the brush. Or perhaps rent an angle grinder and get one of those wood carving attachments. But I think that maybe those cutters cut too smoothly so it won't have the desired effect.

So I'm asking for advice. What is the most effective method of turning milled lumber back into rough cut?

thanks, Doug

[Fly-by-Night CC]

I don't think the angle grinder would work - I've used the wood cutters in mine and it does leave a pretty smooth surface. Plus you'll have small swirls instead of what you're after.

Are you after the large saw blade swirls plus the fuzz? Or just the fuzz?

You could try a floor sander with very coarse grit disk - 24 grit or heavier still - pulled along the length of the beam - then pressure wash it to raise the fuzz.

Test, test, test before attacking your glue-up!

[john]

One thought would be to sandblast the surface

John

[fredfighter]

How about an adz or a broad axe?

Or a scrub plane. Or a jack or smaller plane with 1/8" of crown ground into the blade.

If you are going to buy a tool to put a rough hewn surface onto wood, why not buy a tool commonly used to roughly hew wood?

[Charley]

If I had to do this, I think that I would try to find a local saw mill and get some "real" rough sawn lumber, then make a thick veneer out of it, maybe by planning one side, and then cover the beam with it. It's quite difficult to make a smooth board look rough sawn. You just can't get it that rough and random looking enough so that it looks real, at least not without a whole lot of effort and time.

[Toller]

I had to roughen some lumber to use for bat houses. An angle grinder at a low angle works really well. It will take a little practice to get it even, but I am sure it can be done. A regular grinding wheel, not a woodcutting thing.

[dadiOH]

Chain saw skimmed along the sides.

[George]

What does "rough cut" look like? Band mills produce a different look than circular saws, and neither looks like hand-hewed or pitsawn. The answer is to make the outer surface of your beam out of the outer surface of the lumber that looks like what your client thinks is rough cut. One good surface per board, miter to join almost invisibly.

Sandblasting and wire brushing, especially after charring, make nice weathered looks, if that's what you're after.

[Andy Dingley]

Scrub plane, with an especially pronounced crowned iron. if you don't have one, make one from your roughest #4. Break all the rules of planing and work short strokes, varying the pressure to make long scallops, not a smooth surface. You're trying to emulate adze work.

You can also use a Japanese spear plane (like an engineer's scraper) but this is _the_ most difficult-to-use-well hand too I own! A curved spokeshave or travisher might do it too, but the scrub plane is easier.

Don't wire brush or blast it. That will make it look _weathered_, not rough-cut. The shaping will follow the natural resistance of the timber, which in most softwoods means that annual ridges effect.

[fredfighter]

OP first said the architect called for rough hewn. Later that was morphed into rought cut which is not the same appearance. He first must decide what he wants it to look like, then figure out how to achieve that effect.

[gregg]

Didn't they chop or saw down a bit, at right angles to the long dimention, at intervals of a few feet, then take a broadaxe and work lengthwise to knock off the chunks?

So maybe hit it with an axe or saw every 2 or 3 feet, and then take the scrub plane idea people have suggested and hog off some wood - leaving traces of those right angled cuts.

Replicas of 15th-19th century nautical navigational instruments, Restoration of my 1919 Herreshoff S-Boat sailboat, and Steambending FAQ with photos:

[George E. Cawthon]

I think Doug needs to get his description in order. the subject says rough sawn and the he talks about rough hewn. The two are not synonymous and certainly don't look the same. Not sure why anyone would want a rough sawn surface--a flat surface that consists mostly of stringy pieces of wood that are 1/4" or so long. Hewn wood is mostly smooth, but not flat if it is rough.

[Mike O.]

We had to do this once on a much smaller scale. We were trying make a

6" x 12" x 8' mantle look rough sawn. We took a hand saw and holding on to both ends of the blade, dragged it down the length of the beam. You have to keep repeating this over and over until things start to blend together. Something as large as you have, I might try dragging a chain saw as someone else here suggested.

Mike O.

[Knotbob]

Put a worn out band saw blade on backwards and feed your stock past it at a skewed angle (or something like that). Many years ago when I worked in a millworks shop we milled cedar and cypress parts for doors and windows and then I ran the stock past the bandsaw blade to give it the rough cut lumber look.

Robert

Doug wrote:

[CW]

Shoving a 26' beam through a bandsaw should be fun.

[simoogle]

I think you must make a decision between rough sawn, rough hewn, and distressed. Probably need to try a sample of each to decide. The advice you've received so far will help with each. Rough sawn will require resawing or roughing the face with a saw (duh), bandsaw, chainsaw etc. Rough hewn requires hewing the timber with an adz, plane, scoop, gouge, or whatever you have. Distressed is cutting, incising, beating with a chain, drilling worm holes and smearing with various "staining agents." It's the look you're most comfortable with. For me I would narrow the beam on a bandsaw by one kerf each side for the rough sawn look. I have powerwashed soft woods for a raised grain look, but I don't think thats what your looking for. I'm a big proponent of 4.5" Makita grinders, but you'll really have to be "random" to get a desired effect. Good luck. Tell us what you decide on.

Jerry

[bridger]

especially one that is already installed.

[Doug]

I guess what I want is a beam that looks old barn beamish, weathered and distressed are prolly more what i had in mind than rough hewn. Just something old and natural looking rather than 2 by 10's glued together. I've had lots of good advice, however, it's up in place so it's kinda difficult to put it through a bandsaw now. My wife is skeptical about sand blasting - seems a bit messy. Perhaps the chain saw would work (I'm going to have a sore neck tho'). I'm still kind of partial to the concentrated wood brightener - you know, the stuff for cleaning an old deck. Might make the appearance look stringy and fibrous but that beats smooth.

I'll let you know how it turns out.

-Doug

[bridger]

sandblasting is likely to be your best bet. have it done by a competent contractor. they'll handle keeping things clean.

[Bruce Barnett]

You can try a steel bristle brush. This will wear away the soft wood between the grain. Dent it with a hammer, etc. I use tinted wax (Briwax) in the cracks to add age.

The brush works with soft woods - e.g. pine.