Are these walnut medullary rays?

[Craig Parker]

Are the lines in the photos medullary rays? I've only used walnut one time and it didn't look like this. The panel in the photos is 14" x 12". The lines in the photos are approx. 1/16" width and 1 -2 " in length.

Craig

[Ted Wong]

Yes those would be medullary rays. It is a common occurrence in many species when quarter-sawn.

[Dave MacArthur]

Actually, all I really see in those photos are just growth rings from quartersawn wood that has been bookmatched? That's the left-right running lines in the photo. OK, I looked again since I know you're seeing something, and there are some up/down running lines on the right side of the board and left side, none really in the middle, and that does look like the rays. All trees have them, parenchyma, to store food in, they're just bigger in some trees than others. If they're just a couple cells wide, then you don't hit them as regularly in a radial slice, so you might get some separated by 12" or so as your board appears. And if they're just 10 cells tall or so, they appear as just lines like that. In white oak, the rays are thousands of cells tall, appearing as 1" bands or so, and 20-50 cells thick so they get sliced through with regularity in a radial (quarter sawn) slice. When you slice slightly off the exact radial, "Rift sawn", they you will pass through many more bands of parenchyma, but they'll appear as ovals, like in "lacewood".

Incidentally, it is primarily these bands of living food storage tissue running from the center of the tree to the bark that make wood expand and shrink at a different rate in the radial direction than the tangential direction--you can think of them as "binders" or "stiffeners" in the same way that grass in brick is, all bonded to and woven into the tree-ring layers with their inflexible longitudinal long axis running from center pith to bark, and keeping the wood from flexing/moving along the radial axis as it changes moisture content. There are no such stiffener cells running around the tree rings tangentially, so there the cells are free to expand and contract in that direction without medulliary ray opposition. This makes wood move roughly twice as much tangentially as radially.

[Paul Grothouse]

Assuming you are not talking about the disturbance in the grain (caused by a knot or some other defect, that has been sliced out of this veneer), and are talking about the repeating figure in the panel. This is not a medullary ray, you have a bad veneer or poor sanding techinque that is causing that figure to show when stained. I would try resanding 100, 120 and 150 grit, then restaining.

[george wilson]

Some species like spruce,which do not have pronounced medullar structure,show "silking". That is a discreet medullar structure you might be seeing.

[John Coloccia]

My understanding is that Walnut has practically invisible rays due to their almost microscopic or nearly microscopic size. I've never seen anything like that with walnut. That said, if you had posted a picture of that piece in a "what kind of wood is this thread?", walnut is not one of the woods that would have come to mind. Are you sure you have walnut there? It doesn't look anything like walnut to me, especially the middle photo.

re: the silking
Yeah, boy if you've never seen it before, it can be quite stunning. I have a billet of spruce here I'm using to split off bracing. When you split it perfectly quartered, the surface looks like it's been candied! It's amazing.

[Jim Matthews]

The walnut I use is almost purple in hue, on the long grain side.

This looks like oak veneer that has been stained with a Miniwax product to simulate walnut.

http://www.veneersupplies.com/produc...awn-4-x-8.html

What is on the other side of the panel?

[Tony Bilello]

........I've only used walnut one time and it didn't look like this. ...........

Craig

I think that is because this is not walnut. Looks like some inexpensive plywood that was stained.

[george wilson]

A bit hard to tell correctly from pictures,but the strong grain does look like it could be oak. BUT,if it were,you'd see the very strong medullar rays IF it were perfectly quartered.

[Craig Parker]

Paul,
I think you are right. I will re-sand the panel again and see if the lines go away. Thanks.

Craig

[Pete Bradley]

+1 for red oak veneer that could use more sanding (with care of course not to go through it)

[Dave MacArthur]

LOL...
this gets my vote as "biggest spoofer post of April"!

I looked at the edge of the board and thought it looked like stained plywood, but then thought surely no one would post a question about walnut if he had a chunk of oak plywood he had stained... you got us, good one. So, is it really a piece of plywood you stained, or a solid chunk of walnut you glued up?