Differentiating White and Red Oak Lumber

[Bob Smalser]

http://pic20.picturetrail.com/VOL12/1104763/15559999/269185095.jpg

The best method is under a scope using cell structure comparisons contained in botanical keys, but if all you need to know is whether or not you have oak suitable for use in boats, you can accomplish that just as well using a razor blade and 10X hand lens. The 10X hand lens used in sunlight will provide much greater definition than these photos.

What makes the White Oak group of oaks suitable for marine use (and oaken barrels), is their large, earlywood pores (the fresh, new wood formed each Spring) are clogged with whitish, waxy tyloses that water won't penetrate. The Red Oak group of species lack these tyloses, allowing water to penetrate and the wood to literally weep and seep at the end grain. This combined with other factors causes the Red Oaks to be subject to the rapid onset of mold, fungus and rot.

http://pic20.picturetrail.com/VOL12/1104763/15559999/378363790.jpg

White Oak end grain. Note the whitish tyloses clogging the large, earlywood pores forming the pith or inner edge of each annual growth ring.

http://pic20.picturetrail.com/VOL12/1104763/15559999/378363794.jpg

More White Oak end grain.

http://pic20.picturetrail.com/VOL12/1104763/15559999/378363796.jpg

Red Oak end grain. Note the relatively clean earlywood pores.

A home method to test for Red Oak is to cut it into short soda straw sections and see if it will blow bubbles into a glass of water. This generally isn't a very reliable method because sawdust from crosscutting the sample often clogs the pores. If you use it, then slice away the end grain and any sawdust contamination first using a razor blade. The 10X hand lens is more reliable.

http://pic20.picturetrail.com/VOL12/1104763/15559999/378363805.jpg

Blackjack Oak. In the Red Oak group but here the pores are clogged with sawdust, not tyloses.

http://pic20.picturetrail.com/VOL12/1104763/15559999/378363800.jpg

More Red Oak lacking tyloses.

Continued......

[Bob Smalser]

Continued....

http://pic20.picturetrail.com/VOL12/1104763/15559999/378363810.jpg

Live Oak end grain with tyloses.

http://pic20.picturetrail.com/VOL12/1104763/15559999/378363813.jpg

More Live Oak.

http://pic20.picturetrail.com/VOL12/1104763/15559999/378363808.jpg

Bur Oak end grain sliced clean using a razor blade. Tyloses are definitely present, indicating Bur Oak is a White Oak and boat wood.

[Lew Barrett]

http://pic20.picturetrail.com/VOL12/1104763/15559999/378363794.jpg

Nature's beauty is abundant even in these micros. This looks like fine lace, doesn't it?

[Tom Hoffman]

Blow in the ends of a small sample put the other end in a glass of water. Red oak should blow bubbles, white oak shouldn't.

[wizbang 13]

put it all in the fireplace

[P.L.Lenihan]

Thank you Mr.Smalser for your always informative and educational type postings about tools and wood. I've never failed to glean a new bit of useful information from them!


Cheers!


Peter

[floatingkiwi]

Bob, are you still about? Tell me what you see in these two shots, please.

http://im1.shutterfly.com/proctaserv/47b9cf03b3127ccef8f83903332000000037100AZtGbhu3cs2 QPbz4a

http://im1.shutterfly.com/proctaserv/47b9cf03b3127ccef8f8ae2473d400000037100AZtGbhu3cs2 QPbz4a

[floatingkiwi]

And this wood. Is it white or red?

http://im1.shutterfly.com/proctaserv/47b9cf02b3127ccef8fa262faa8700000037100AZtGbhu3cs2 QPbz4a

http://im1.shutterfly.com/proctaserv/47b9cf02b3127ccef8fb38788a9300000037100AZtGbhu3cs2 QPbz4a

[Bob Smalser]

And this wood. Is it white or red?

You can't tell much looking at weathered samples.

Make a crosscut into fresh wood. Plane off the sawmarks, then take a fresh slice using a razor blade.

[floatingkiwi]

That is what I did.

[Bob Smalser]

That is what I did.

Why is it gray, then?

California has some oddball oaks that grow nowhere else. A score or more of them, too. Half your pores are plugged and half appear clear in both samples. But there are other factors involved in ID....PM me for an address and mail me a few sample slices of end grain. Perhaps I can key it out by cell structure under the scope.

Was this just lumber or do you also have bark and old leaves to look at?

[floatingkiwi]

That is good of you to offer to examine physical examples. Ya can't beat that, however it MAY not be necessary.
The first photos are of odd pieces of furniture that I have cut up and have used, are using or contemplating using, in my boat for various , relatively non structural , above waterline applications. Like the corner posts I spent some time on getting damn spot on. If it is red oak,(the first shot),I fear I may have to eject them from their little niche.
The second post is 2 shots of a piece of the floors ,( left over from rebuilding them), that have been 50 years enveloping wet keel bolts in my folkboat.

Whad'ya think about that?

[Elcoholic]

Build a boat. Frame with oak. If it rots and sinks, it's red oak.

[the_gr8t_waldo]

i've been useing the scratch n sniff method. if it smells like horse poop-it's red oak. i have to admit looking at the pours, sounds a bit more definitive.

[Ron Williamson]

Being porous is bad for the same reasons that it's good.
It will accept preservatives more readily too,so dose it up and sleep well.
R

[bluedog225]

Any objections to using red oak for interior applications or above water on the deck if you heat it up and immerse in spar varnish (thinned), and then coat with several coats.

I tend to think the pores can be filled up with varnish and thereby prevent the entry of water. Just a theory. I still would not use it for frames or below water.