Struggling getting started w/ Bowls
#18
(12-21-2018, 09:47 AM)DFJarvie Wrote: Just a word on the cracking. For green bowls you want to rough turn the bowl and leave the wall thickness around 1 inch and the let the bowl dry. It could take up to a year or more.


If you read my first post, and look at the pictures, you'll notice the bowls are ~3/4, and it took 6-8 weeks to cure to equilibrium in a 50% RH.  Year per inch is for planks in sheds.  
You can see the shrink measured along and across the mortise, which is what I use to determine when they're cured.  When I have lost an eighth across a 2" mortise, things are good.  Weighing and fussing isn't something I fancy.  If you're a tenon guy, make the tenon a bit more generous and look for about the same shrink rate.

On thickness of the walls and bottom, you'll notice my roughs are in total violation of that "rule" as well. Stopped losing bowls when I figured out the diagram in Hoadley twenty five years ago.
Better to follow the leader than the pack. Less to step in.
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#19
I rough turned a bunch of blanks a few months ago and got them to a rough shape with a bottom tenon. I did take a little out of the inside and set them to dry. I learned that if I sealed the ends of the logs you still checking. So far no checking with the new batch.
Don
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#20
I'll leave the turning green blanks to the others, they all gave you good information. Now, turning plywood is not for the faint of heart or inexperienced turner. Even the upper grades of plywood can be a nightmare to an experienced turner. I've been segmenting for a lot of years and I refuse to do any plywood other than spectra ply. Generally speaking dried glue is harder on a tool edge than wood. Plywood is full of glue and the grains alternate with every layer, it kills tool edges faster than any exotic I've worked with. Until you get your sharpening down and technique figured out stay away from the plywood. You'll just end up frustrated if you keep trying it.
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#21
Linking this old reference on bowl gouge bevel angle because bowl styles or shapes do require different bevel angles; see page 13.

http://s12166.pcdn.co/wp-content/uploads..._Notes.pdf

Lot of turners like the 1/10 rule rule of thumb: if bowl blank 10 inches in diameter turn to 1 inch thickness. Seems to work on smaller & larger diameters like already mentioned.

Also already mentioned rough turn to uniform thickness which I do and like others my bottoms may be little thicker.

Lot of Bradford Pear trees in my town, stink when it blooms, fruits are a mess, and not a very hearty tree. Disease, and storm damage take their toll on them.

Like many fruit woods need little luck to keep bowl blank roughs from cracking. So rough turn Bradford Pear little thicker next time. Some non fruit wood species will allow turning thin to completion or rough out less than an inch. When in doubt leave them thicker.

Good luck with it!
Bill
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#22
Try your hand at segmented turning. You work with dry wood only so no concerns about cracking. You also mostly cut long grain so catches are due to user error mostly. Final size is not determined by a block size, unless you are sandwiching a burl block or something as part of your design like these:

   
Cellulose runs through my veins!
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#23
SteveS, couple of outstanding segmented examples! Segment turning also has steep learning curve and requires additional woodworking machines & accessories. Well worth the effort if have the patients and enjoy doing it.

Turning found or wet wood definitely a challenge going from unknown MC to finish piece! If find R. Bruce Hoadley ‘s article on “Drying Wood The Fundamental Considerations,” will learn that old myth of takes one year per inch for wood to dry. Depending upon several factors like where you live, & wood species rough turn bowl blanks dry or reach ECM in months not years.

That one inch per year old rule of thumb for some pine boards but not all.
Bill
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#24
I'm another guy who recommends finding a local turning club.  Live instruction will speed your learning curve up considerably.  Well worth the effort IMO.
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