Thuya burl finished pen opening (cracking?) up. Reasons/Fixes?

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jschoolcraft

jschoolcraft

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I showed off this pen in Burls really steal the show. So as not to bury the lead: after a week or so of sitting in my office the tube felt a bit sticky and there were cracks on some of the swirls in the burl:

[EDIT: Must have used a private image]

IMG_9474.jpegIMG_9475.jpegIMG_9476.jpeg

This is a picture after I disassembled the pen and put it back on the lathe. I'm not sure what happened. More importantly I'm not sure if this is a one off thing or how I can prevent it in the future.

I'll include the original pen image at the end but it came off the lathe silky smooth and I've been finishing all my pens the same way for the last month or so:

  1. Sand through the grits (120 - 600)
  2. Wipe down with alcohol (isopropyl. I don't have denatured and haven't tried to find everclear or similar)
  3. Apply Mylands sanding sealer
  4. Use Yorkshire Grit abrasive paste
  5. Apply 3-4 coats of Doctor's Workshop Pens Plus (applied at 100s RPM, then friction at 2500-3000 RPM, let it cool down for a few minutes between applications)

I haven't applied Renaissance Wax since switching from Mylands Friction Polish to Pens Plus.

This is my only pen, that I know of, that has done this.

Original pen post:

img_9460-jpeg.381877
 
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I've had redwood burls that grew, shrunk, moved, or something that made my CA finish craze or crack. Sanding and refinishing has always fixed it for me. I don't know what the cause was though. I've speculated that it was because the burl absorbed more alcohol and I didn't let it dry out long enough before finishing. I've just made it a practice to let burls dry for an hour or two between cleaning and starting to apply a finish.

Mylands sealer and Pens Plus are both shellac based, and are soluble in alcohol, so maybe residual alcohol in the burl softened them back up???? - Dave
 
egnald said:
I've had redwood burls that grew, shrunk, moved, or something that made my CA finish craze or crack. Sanding and refinishing has always fixed it for me. I don't know what the cause was though. I've speculated that it was because the burl absorbed more alcohol and I didn't let it dry out long enough before finishing. I've just made it a practice to let burls dry for an hour or two between cleaning and starting to apply a finish.

Mylands sealer and Pens Plus are both shellac based, and are soluble in alcohol, so maybe residual alcohol in the burl softened them back up???? - Dave
Click to expand...
That's good to know. I don't soak down the blanks, I cover the top of the bottle with paper towel and turn it over then apply it. I think in this batch of 4 pens I sanded wiped down with alcohol and then started sanding the next pen before I started with sanding sealer and the rest of the process.

I'd guess at least 30 minutes between alcohol application and sanding sealer. Anything is possible but I would have expected the alcohol to have fully evaporated in just a few minutes.
 
jschoolcraft said:
That's good to know. I don't soak down the blanks, I cover the top of the bottle with paper towel and turn it over then apply it. I think in this batch of 4 pens I sanded wiped down with alcohol and then started sanding the next pen before I started with sanding sealer and the rest of the process.

I'd guess at least 30 minutes between alcohol application and sanding sealer. Anything is possible but I would have expected the alcohol to have fully evaporated in just a few minutes.
Click to expand...
I agree, 30 minutes should be plenty long enough for alcohol to fully evaporate. - Dave
 
This happens to me far too much. I have a beautiful Thuya pen that looks just like yours and has been placed in the pile that need disassembly and redone. I almost always trash the plastic threads when I disassemble.

I just bought a pile of stabilized woods because this is too heartbreaking. The dry winters and humid summers in PA are too much.
 
It was not stabilized. Maybe going from the dry, cold, unconditioned garage to sitting in my office? I guess chalk it up to learning experience :)
 
"going from the dry, cold, unconditioned garage to sitting in my office"

This is a learning curve for those new to woodworking, and for pen makers also. Here are a few facts:

Wood moves! There are books on this. Humidity swings along with temperature swings causes wood to move. The primary culprit though is the humidity. It affects normal un-kiln dried wood the most. And knots and crazy wood grain sections reveal the movements the most. There are some woods that move more than others and a few woods that have imperceptible movement with humidity swings. Then that are woods that move in certain directions more than others.

In furniture making and in tables more specifically, some tables have bread board ends. "Breadboard ends help maintain the stability of the table panel and prevent it from cupping. They also cover end grain, which can help prevent cracking. "
Breadboard ends allows for the wood to move. If it is totally glued or screwed or nailed to the other wood, it will crack due to humidity swings.

Wood moves, even in small pieces of wood as you showed in your photos. Stabilizing helps stop this expansion and contraction.

Quite a few pen turners have purchased large paint pots and built their own stabilizing pot.

Here is a true story done more thousand times over to wood workers and shop workers around the world. Before steel shaft, fiberglass shaft and plastic shafted hammers, there were only wood shafted hammers. Wood shafted hammers had a wedge placed in the wood on the top side to keep it tight. Then in two to four years, the wood would come loose. Another nail or wedge would be driven/hammered in. The next year it would be loose again. The real culprit was humidity. As daily humidity swings came and went, the increase of humidity would cause the handle to swell just enough that it would crush the outer cellular layer of wood. Then the humidity swing downward caused the wood to decrease in size just a very tiny bit. Then the next swing up of humidity would begin crushing the next level of cellular layer. Over two or three years, the wood hammer would become too loose and have to be replaced.

Wood moves. Stabilizing helps!
 
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