Question Re Southern Silky Oak "Sap Veins"

I've been making various furniture items using Southern Silky Oak (Grevillea robusta). Recently, I've noticed that some boards have what I think are "Sap Veins" in places. The veins are pink to red in colour, and when they occur they follow the growth ring along the length of the board. So far I've been avoiding these boards with Sap Veins, wondering how I could work around these "defects" with minimal wastage. The Sap Veins mostly seem to appear in the Pink coloured Southern Silky Oak. So far I haven't seen any Sap Veins in the more yellow coloured Southern Silky Oak.

Recently I decided to try using a small piece of the Silky Oak with gum veins in it, as a Coffee Table Top, mainly as a test to see how durable the Sap Veins are, and what the timber with that defect looks like with a finish on it. I've included two close-up photos of these defects - double click the photos to open a much larger version.

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Now that I've seen the timber with the Sap Veins finished with 3 coats of oil based PolyU, I think that I'd be happy to have the Sap Veins appear in some areas of the furniture I'm making.

BUT, does anyone know how stable the Sap Veins are when they occur in Southern Silky Oak. Are these Sap Veins likely to be the source of cracks in the future, or are the Sap Veins stable once the timber has been fully seasoned. (Note the timber I'm working with is down to ~8%, so it's pretty well seasoned.)

Thanks,

Roy

Hmm, I know Grevillea robusta as Southern Silky Oak and varies from pink to yellow, what are you calling Silky Oak? There are many that go by that common name. Or are you just distinguishing between the yellow and the pink?

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Originally Posted by dai sensei

Hmm, I know Grevillea robusta as Southern Silky Oak and varies from pink to yellow, what are you calling Silky Oak? There are many that go by that common name. Or are you just distinguishing between the yellow and the pink?

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Typo fixed. Southern Oak corrected to Southern Silky Oak.

Those 'veins' are quite common. I've had SSO stored for about 10 years, and haven't seen any evidence that it's unstable along them. I include the veins quite happily in furniture and boxes.

:whs:
I stand to be corrected, but I think those marks are the results of minor injuries (insects, heat etc.) to which the tree has responded with kino. Some SSOs have lots, I've noticed, particularly if they grew in marginal conditions. The most prominent I've seen were in a tree that was growing under rather harsh conditions, in Victoria (this is naturally a subtropical species that prefers a bland climate).

Small 'veins' like you show in the pics should be fairly sound. The wood tissue seems to be mostly continuous, & though it's probably a bit more fragile along the vein, I doubt it would be seriously so. Larger veins can be voids filled with gum (kino), and the tree I mentioned had quite a few of these. I wouldn't want a dovetail pin landing in the middle of something like that. If the veins are narrow & look pretty sound, I don't worry about them too much structurally, but they can be a big nuisance aesthetically. I don't like random black marks on my highly finished surfaces! :no:

Cheers,

I think those veins are needed in southern silky oak. Without them, asethically in my opinion, its boring because most of the timber doesn't show those medullary rays which help it look less busy. For the medullary rays to look good it has to be spot on 1/4 sawn else no rays. So most of it, imo, looks like gravel without the veins. Though, your supposed to love silky oak around here, like cedar, regardless, even though personally I think, most of the time you end up with work that looks like gravel. :?

I've been told to make sure you cut out the sap in silky oak. Falls away/disintergrates over time. I haven't seen that personally happen with the things I've made, but because an elder told me who has had failure with it, and feels an incredible need to know better regardless, to avoid a debate, I would have to say he's right. :?. But he would have good reason to be right, but weather it pertains to relevance of this discussion is beyond me. :?

basically, I do think the veins save the look of busy southern oak. The long thin ones that extend the length of the timber look best imo.

just an opinion. not an expert on SSO(southern silky oak), 2 cents worth.

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Originally Posted by JDarvall

.......I've been told to make sure you cut out the sap in silky oak. Falls away/disintergrates over time. I haven't seen that personally happen with the things I've made, but because an elder told me who has had failure with it, and feels an incredible need to know better regardless, to avoid a debate, I would have to say he's right...

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Jake, I have to agree with your 'knowledgeable' friend - the sapwood on SSO is not good stuff to include in anything you hope to last a while. It does rot extremely quickly if it gets wet, and borers just can't get enough of it. I left the sap on the first couple of logs I sawed up, to maximise yield, & stacked them outside (well-covered with sheets of iron) to season a bit, but most of the sapwood rotted very quickly. What didn't rot ended up so borer-riddled it was useless anyway. That was partly my fault because I was a bit slow to paint the ends, but you still get borer, even when ends are painted.

As to the aesthetics of the stuff, well one man's meat & all that. Personally, I prefer northern SO (Cardwellia sp.) if it's an 'oak' look you're after, not only because it has larger, more obvious rays, but because it is a firmer wood. I find SSO can be a bit soft (though not as soft as Aust. Cedar). However, SSO will polish up nicely, if that's the look you want, while NSO is coarse-grained & doesn't come up anywhere near as nicely.

As you say, it's all a matter of personal taste. If I get any heavily veined SO in future, I'll keep it for you...... :;

Cheers,

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Originally Posted by IanW

As you say, it's all a matter of personal taste. If I get any heavily veined SO in future, I'll keep it for you...... :;

Cheers,

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cheers big ears. :) as long as its a swap for something you want.

I think its ok to use as long as it not too heavy a vein and discontinues enough with plenty of supporting meat, and not being pressured by a joint.

as for the sap. I sense there's an angle where sometimes its ok to use. But because its hard to identify what saps good and whats not a sweeping thought of it never being used is best I suppose
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But I reakon there'd be some bloke out there who has noticed a characteristic of some kinds of silky oak sap thats fine to use. Maybe there's been many already, but have taken it with them to their grave. Maybe sap that can be used say, under paint or in some functional but unseen part of a cabinet.

I used a little bit in some things that didn't fall apart. I remember once a short piece of silky oak that was heavy in sap, I couldn't stop looking at because of branch swirls and colours. I couldn't chuck it, it looked so pretty, despite the sap. So I just turned it into a cutting board where it sees a lot of water. For some reason that particular piece didn't rot. Maybe it has something to do with the greasiness of some silky oak.

:)dontknow.

Jake, yes, I reckon you could get away with using the sapwood in lots of situations, as long as you keep in mind that it isn't durable if moisture can get at it, and if those species that are highly susceptible are protected from the wood-munchers. Once made up & finished & living indoors, the former situation should be taken care of, while sealing wood with most finishes slows down borer infestation (don't forget underneath, which is where they like to begin their dirty work).

Most books & 'old blokes' warn against use of sapwood, and there are good reasons, as I'm sure you are as well aware as I am. One good reason is because sapwood is usually under tension, and can cause you grief during building a piece. The other main one is that sapwood usually contains more sugars and other nutrients tha wood-munching critters like, so is always the first to be attacked.

But if you haven't ever broken 'the rules', you ain't lived, man! As you say, there are good aesthetic reasons to want to include sapwood on occasion, & I've certainly done it, quite a few times myself. You can overcome the tension/moving problems with care & perseverance, and in many woods, the sapwood isn't as vulnerable to insect pests as it is on the more 'sensitive' types (though SSO is unfortunately in the latter group). But as often as not, you'll get away with it, at least for your lifetime........ :U

Cheers,