Interesting pattern in Padauk

[rwyoung]

I made last night my first fountain pen and used Padauk. On close inspection today at work with higher power magnification loupe and microscope than I have at home, I can see a series of rings circling the wood. They look very much like finger print ridges as they periodically bifurcate and in both directions with and against the rotation on the lathe.

The sanding was done to 600 with cleaning between grits followed by CA/BLO. After each grit with the lathe on, I would wipe down and then run with the grain. I'm not seeing scratches running along the body nor do I see what I would consider a sanding scratch concentric to the body.

I'm pretty sure these aren't scratches, they just don't look like that, its almost like a growth ring pattern? Anybody else seen this in Padauk or other woods?

Image capture from screen. I've marked the bifurcating line, top left hand of the four with the other three showing the jog to accommodate the "new" line.

 

[Russianwolf]

1) must be sapwood since I've never seen white Padauk (other than the sapwood). :tongue:

2) could it be your fingerprint that is now under your CA finish. If you touched the barrel before applying the CA for example. CA is known to raise fingerprints. You then coated the raised fingerprint with more CA encasing it under the finish. Just a hypothesis.

 

[rwyoung]

1) must be sapwood since I've never seen white Padauk (other than the sapwood). :tongue:

2) could it be your fingerprint that is now under your CA finish. If you touched the barrel before applying the CA for example. CA is known to raise fingerprints. You then coated the raised fingerprint with more CA encasing it under the finish. Just a hypothesis.

#1 don't trust the color. The screen capture seems to have shifted things to a lower contrast. The color of the pen in sunlight is correct for Padauk, a deep orangy-brown.

Not #2 as the rings are concentric along the length of the shaft (and I kept my grubby fingers off). The close-up just shows a very small section at about x14 magnification. I cherry-picked an area that had a clear bifurcation.

 

[RussFairfield]

With enough magnification, even the smoothest and glossiest of surfaces will look like a dirt road.

 

[rwyoung]

With enough magnification, even the smoothest and glossiest of surfaces will look like a dirt road.

Yeah, but it is fun to play with the microscope. From a hands-on, Mark-I eyeball standpoint it is just great. Its the engineer-geek that wants to know the why... :glasses-nerdy: Plus, as a byproduct of the way JPG compress works it shows up in high-contrast areas (reflections) when taking a photo. JPG compression has a tendency to emphasize "Mackie lines", those lines that appear when you have large contrast changes.

 

[rwyoung]

I'm pretty sure now that what I'm seeing are akin to medulliary rays. Looking at different parts of the wood and unfinished (but sanded) wood I can see the various patterns repeating. In some places they look like concentric rings, other places I see them diverge into rings and loops. Seems to be a correlation between the pattern the little rings make and the density of the wood.

None of these look like mechanical scratches or sanding marks.

Any way, it is was an interesting exercise to look closely at the wood structure.

 

[mick]

Rob, I've seen this pattern often in Paduak.....under an extremely glossy finish it will almost look like it's a pattern "printed" on the wood

 

[holmqer]

I've seen that pattern in many woods, I suspect if I had the patience, I could find an explination in one of Bruce Hoadly's books.

 

[leehljp]

Rob, I've seen this pattern often in Paduak.....under an extremely glossy finish it will almost look like it's a pattern "printed" on the wood

Same experience here. Quite common, and as other have said, other woods often have this.

 

[rwyoung]

Rob, I've seen this pattern often in Paduak.....under an extremely glossy finish it will almost look like it's a pattern "printed" on the wood

Bingo! That is exactly what it is looking like!

Glad to see a couple others have seen this too. When I first noticed it I got a little bit paniced thinking I'd screwed up the finishing somehow...

 

[jimofsanston]

Too deep for me

Now i have heard everything. We all must be going nuts. We are not using microscopes to inspect things. People are going to start bring out the body harness and setting up the paded rooms by the the boat loads if we keep this up:glasses-nerdy::glasses-nerdy::befuddled:

 

[Tn-Steve]

I wonder if that is what contributes to the Chatoyance that some woods have? Just a random unschooled guess?

Steve

 

[TurnedAround]

"finger prints"

What you are seeing are bands of parenchyma. They are basically storage cells in the wood. Here a photo that is close to the magnification (I think) of the 14X that you used.File is Insight
View attachment Insight.pdf

Got this off the site for Inside Wood. http://insidewood.lib.ncsu.edu/description.6

That's my guess.Or they could be what's called "sclariform perforations" That look like the left side of this photo. File is Insight2
View attachment Insight2.pdf

Sorry to be so geeky but wood anatomy and xylology are hobbies of mine.

Here's my basement lab. I call it "Wood Shop II" :

 

[leehljp]

Here is a picture of the Padauk rings from the first pen that I made for me. It is not a clear pict but I didn't have a good digital camera back then.

 

[rwyoung]

What you are seeing are bands of parenchyma. They are basically storage cells in the wood.

Here is a picture of the Padauk rings from the first pen that I made for me.

Exactly! Nailed it! I feel a lot better now. :glasses-nerdy:

Cool web link there TurnedAround, thanks.

 

[rej19]

Yep I'm a rookie.

After reading this post and seeing the following terms: bifurcating,mackie lines, medulliary rays, chatoyance, parenchyma,sclariform perforations, and xylology I am convinced that I have only began to break the surface of pen turning. I have a long way to go. I may have started way to late in life! Just kidding or ......... maybe not.

 

[Tn-Steve]

After reading this post and seeing the following terms: bifurcating,mackie lines, medulliary rays, chatoyance, parenchyma,sclariform perforations, and xylology I am convinced that I have only began to break the surface of pen turning. I have a long way to go. I may have started way to late in life! Just kidding or ......... maybe not.

I know, it's like an episode of CSI. I'm only at the stage where I can identify wood if it has a label on it. (ok, maybe just a little bit better than that). I am most impressed by the technical expertise found here.

Who'd a thunk it?

Steve

 

[ColoradoHermit]

Seen it before

I've seen rings like this before. I was turning some Canary wood, had sanded it down to the 12000 M M. After I got a couple of coats of CA finish on it I noticed these tiny rings around the wood. I thought at first that it was from sanding but they were too even. They were so even that they looked like tiny close groves in a LP Album.
Just to be sure they weren't there because of my sanding I turned all the finish off and started over. I was very careful to sand with the grain with each sheet of the Micro Mesh before going to the next one. When I got to about the 3600 or 4000 grit I started seeing the rings again. I went ahead and finished the pen and you cant see the rings unless you're looking for them.
I don't know why they are there, but they are too evenly spaced to be from sanding. And they still look like little groves on a music LP Album.
So far I've seen them in the Canary wood, some of the pieces of Padauk, Yellow Heart, and in some Brazilian Tulip wood, and some Blue Mahoe from Puerto Rico. I think I've seen it in some others but can't remember what ones right now.
They are so even and small I guess that they could be some sort of growth ring or something like that. I'm only a rookie at this and been turning pens for a year. But every time I order some wood I always get at least 2 or 3 kinds that I've never seen or worked with before along with some more of the ones that I like.
Any who, that's my two cents on it.

 

[leehljp]

Just to be sure they weren't there because of my sanding I turned all the finish off and started over. I was very careful to sand with the grain with each sheet of the Micro Mesh before going to the next one. When I got to about the 3600 or 4000 grit I started seeing the rings again. I went ahead and finished the pen and you cant see the rings unless you're looking for them.

LOL! :biggrin: I did the same thing! I saw the rings and then questioned myself if I had in fact sanded it properly. I didn't notice them at first - until after finishing. So, Like you, I turned it back down to the wood. AND that was on the pen in the picture above.