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i have a friend that owns a mill down the street and whenever he comes across something unique he sets it aside for me. a couple of months ago he resawed and gave me some wood from an old house from somewhere in michigan. it was a large stair tread that a customer wanted him to duplicate. it has some tight growth rings, im sure there are about 50 an inch. the issue is that there are some dark lines throughout showing what i would guess are pitch pockets. they dont appear to have any dimension or make the wood weak. just looks like stains. i wouldnt mind using this for some ukulele or guitar tops since they look to have a lot of character but i wanted to get everybody's input on this since ive never seen a guitar or uke with these marks. below is a scan of the wood the pencil marks show each inch.

link to image
http://yfrog.com/40scanimage001yj

First, you do want to make sure you are dealing with spruce, not fir or pine since they may not be so desirable for your purpose. The picture looks a bit on the 'pink' side for spruce.
Pitch streaks are OK in something you build for yourself, but most folks like the look of 'clear' top woods, it seems, so if for sale or for a gift a different top might be a better bet. (Reasonable-looking tops aren't very expensive.)
Myself, I kinda like the stripey look.
Cheers
John

That looks like Douglas Fir to me and those pitchy streaks are very common in D.Fir. Lots of successful instruments have been made with D.Fir tops. They are "spruce" sounding instruments but have their own tone. As long as the top is solid and won't split when flexed it should be fine. I would use an oil based finish though as those marks can bleed through a finish.

Good luck with it.

Shane

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Canada

I'll go along with Shane on this one. (and most others probably) Doug fir... Those pitch lines are typical on fine grained, old growth timber.

thanks guys for the info. i think i have an idea for what i will use this for.

ill check this one off of my list of dumb questions.

Whatever it is, thin it and put it in front of a powerful light source. If there is any problem-pocket, you should see it pretty clearly.

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Build log

Sunburst.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

Doug Fir vs Larch...

Both look the same, smell the same, tool the same...in fact they are grouped together as one wood and sold as Spruce Pine Fir ~ SPF but often the fir is really larch. Few can tell the difference. However larch is 3-4 times heavier than fir. A lotta tops out there sold as fir are really larch. DF stays green all year, larch losses its needles and looks dead in the winter.

Yes SPF have pitch pockets with fir being the worst of the three however Larch is notorious for pitch pockets. Days, weeks months , even years later larch will just open up a grain line and out pours sap.

Once was doing an arch top...at the scraping stage the pocket opened up rendering an undesirable sound hole by the time I got all that pitch out. Ah yes a bondo moment for sure it was. Fortunately it was an experimental build and not a clients.

Removing a pitch grain line is a real pain. First you split it, then you scrape back to the next grain line on both halves, then you bring the two halves together with just enough pressure to pull through sandpaper...Floss sand edges and reglue. usually comes out unnoticeable but gee dude, ya really gotta need or want that particular piece of wood to go through all that hassle.

Well thats my BS and me sticken to it.


Blessings

Padma

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Audiences and dispensations on Thursdays ~ by appointment only.


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That kind of color is not the same thing as pitch streaks or pockets.

I wouldn't use wood sawn from an unknown timber that had pitch streaks. But if you really want to use it, try baking the tops, which will cause some pitch to bleed out and crystallize some of it, too. There has to be a thread or three around here on baking.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Mr. The has it almost right in the wood classifications. Douglas Fir (Pseudotsuga menziesii) is actually not a true a fir and in British Columbia is classed structurally with Western Larch (Larix accidentalis) for construction and grading purposes (Douglas Fir-Larch). Next is Western Hemlock (Tsuga heterophylla) and Amabilis Fir (Abies amabilis) this group is known as Hem-Fir. Following that is S-P-F which includes all of the spruces except Sitka (Picea species) the rest of the firs except Amabilis (Abies species) and all of the pines (Pinus species).

D.Fir can have crystalized pitch FOR EVER and can start to run at a whim! I renovated one of my houses that was built in 1929 and the pitch was still an issue in those D. Fir 2 x 4's. Again having said all of this I have a friend that builds a few instruments with D. Fir and he loves them!

Shane

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Canada