A couple bowl turning questions

[Gary Herrmann]

I decided to turn a chunk of Catalpa a friend gave me a few months ago. He told me it was a little punky.

I shaped it and started sanding it tonight. There are some spots on the outside and inside that are still rough. Even tho the surrounding areas are smooth. Is that the punky parts or just endgrain?

Maybe I'm not doing it right, but even tho they're getting kinda smooth, now they look like they're little pits filled with sawdust - which I guess they are? Is this normal?

I'm amazed at how smooth the bowl was even after 180 - I guess thats a function of the wood spinning on the lathe. Pretty cool. After I wiped off the sawdust with a papertowel, it also looked really shiny. I guess I'm used to flat work...

Finally, is it just me or do other people smell cotton candy when they turn Catalpa? Especially when I was narrowing down the part attached to the face plate with the parting tool.

I don't even know what I'm doing, and I can see why its so addictive. I lost 2 hours in the blink of an eye.

[Andy Hoyt]

Sounds like minor end grain tear out to me, Gary. But a pic would aid in a definitive diagnosis. When I get those I will give them a blast of air between grits to blow out the dust. This seems to help reduce the holes into nothingness quite well. That said, I've no experience with catalpa, and as such it's also possible that it's something unique to that flavor of wood.

When I think of the word punky it's usually in reference to the wood's degree of decomposition.

[Gary Herrmann]

Good point, Andy. Hope I took a good enough pic.

[Andy Hoyt]

Bust out your 80 grit gouge and get it done.

If your lathe does not dial down to a very low rpm (as in 100 +/- or less) I suggest you first sand the affected area with the lathe turned off and rotate the piece by hand. Once it's gone, blast with air, turn on the lathe and resand the whole piece. Rinse, lather, and repeat with successive grits until you're happy or bored. That's pretty minor looking tearout, so I'm guessing happy will happen first.

Nice looking chunk o' wood!

[Keith Christopher]

You could also try a shear cut to help with that. But 80grit is the most surefire tool for that. :)

[Gary Herrmann]

My lathe doesn't go anywhere near that slow, so I guess I'll start over. Thanks Andy.

I'm assuming that the tearout is due to my technique? How do I avoid that in the future? I assume the answer is practice, but thought I'd ask anyway.

Keith, I guess I'll have to look how to do a shear cut. Another good reason to take a class or make it to an AAW mtg.

[Bernie Weishapl]

Gary watch Bill Grumbines video on bowl turning. He does a shear cut and for the toughest you break out the nuclear weapon of wood turning. The vertical shear cut. Both work well and will get rid of your problem if you get these cuts down pat. Sometimes with the vertical shear cut I start sanding at 220 grit.

[John Timberlake]

I have only turned catalpa once and it turned really nice. I was doing a vase so the end grain was on top and bottom. I also didn't look like the wood you show. Mine was a lot lighter colored and very interesting grain.

[Jim Becker]

A shear cutting technique with the side of a side-grind/Irish grind/Ellsworth gouge will likely get most of that end-grain tearout "gone"...and the every-popluar 80 grit gouge will get the rest.

[Jonathon Spafford]

Just pull away the tool rest and use a cabinet scraper free hand after covering the torn spots with oil or paste wax. Then put the cabinet scraper at about an 85 degree angle to the axis (almost straight up) and give the bowl a couple passes... after about three or four passes most of it should be gone. I really have come to like the cabinet scrapers for shear scraping.

[Reed Gray]

That is tear out. Sharper tools. The lightest cuts you can do (you want little whispy shavings floating in the air). Especially if the wood is dry, you can wet it before doing the last cuts with oil, water or finish, before light/whisper cuts. You can always resort to the 80 grit gouge. I have noticed a peculiar sweet smell in Catalpa, but I didn't like it too much. Catalpa is soft, and more prone to tearout.
robo hippy

[Mike Vickery]

http://www.robert-sorby.co.uk/

If you click here on the video's link their are 2 videos on shear scraping under the multi tip hollowing tool.
I am far from expert but I can greatly reduce tear out using shear cutting techniques with my gouge and I can eliminate the rest using the shear scraping. It still takes me a long time but I would rather turn than sand.