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Leo De Bruin

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Too dry??
Jan 16^th, 2018 at 11:17pm

I have been working on a bunch of birch rough turned bowls. I rough turned them last spring, set them aside to dry to 11-13% MC and then shifted them into my basement where they finish dried down to MC 6-7%. I usually finish turn when they are under 10% but this batch was left maybe too long?? These bowls are hard and almost seem brittle and the tear out is evident on almost every bowl. Sharpening on my Wolverine is good and I use a NRS and oil for my last cuts. I have been at it awhile and have never experienced this.

My question is "can the wood get too dry to work on properly?"

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Ed Weber WR Administrator WR Patron Offline Posts: 8,939 Wilton California USA Gender: JET 1642 Grizzly G0584	Re: Too dry?? Reply #1 - Jan 17^th, 2018 at 9:49am Leo De Bruin wrote on Jan 16^th, 2018 at 11:17pm: My question is "can the wood get too dry to work on properly?" The short answer is yes
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robo_hippy

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Re: Too dry??
Reply #2 - Jan 17^th, 2018 at 11:03am

Well, if you had asked me if wood could get too dry to turn, I would have said I don't think so. Not some thing I have ever run into, well, not yet. I did get a piece of Koa that had spend years in the upper shelves of a shop, and the only thing I had turned that had tear out that bad was coconut palm... I did have to wet the fibers several times to clean up major tear out. I guess a test for you might be to raise the moisture content in them. I am in western Oregon, and this time of year, a month outside, under cover, could get the MC up to 20% or so. Maybe a damp towel over it for a week or so, or inside a plastic bag or box with some water/wet sponge inside as well...

robo hippy

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Ralph Fahringer WR Addict Offline I'm the "Burly" Man!! Posts: 1,629 Ellsworth Maine USA Gender: PM3520b	Re: Too dry?? Reply #3 - Jan 17^th, 2018 at 11:11am I remember turning a piece of KD cherry for a platter and it was almost completely tiny chips and alot of NR scraping to get the piece smooth enough to sand. It's like the wood wants to break off instead of shaving off. Sounds like your wood. It does finally work out but it takes alot more work.
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Ed Weber

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Re: Too dry??
Reply #4 - Jan 17^th, 2018 at 12:00pm

It's the difference between trying to cut a potato chip and a slice of potato.
The wood needs to be dry but not brittle. When too dry, fibers break before they're completely cut. Where they break is where they're weakest, which can be any point along the fibers. When they break near or just below the surface, (where they're unsupported) you get a type of tear-out. I second Reed's suggestions about raising the MC a bit.

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Tony Rozendaal WR Addict Offline WR Rocks! Posts: 990 East Troy, WI Wisconsin USA Gender: Robust AB Grizzly 12x20 Midi Lathe Delta 10x16 Mini Lathe	Re: Too dry?? Reply #5 - Jan 17^th, 2018 at 2:49pm Leo, I know you are no novice, but have you ground the heel off your bowl gouge? It's worth a try. Also, it's an old cliche, but remember the saying "you should ride the bevel, but the wood should not know the bevel is there"? Finding the bevel and then raising the handle a degree or so can help. Hoping this helps.
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Tom Coghill

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Re: Too dry??
Reply #6 - Jan 17^th, 2018 at 6:32pm

I turn a LOT of birch. If the wood becomes punky or you are otherwise getting a lot of fibers being lifted out, try treating the wood with a water based sanding sealer (general finishes works well). After applying a liberal amount (2 - 3 times), an especially to end grain areas, turn it again removing less material than was treated by the sealer. If needed, re-treat the end grain again. When sanded out, treat the entire bowl with this material before your final finish.

This may help you get what your are seeking.

PS - in all cases, I thin this product to 50% strength, using water. It looks milky, but dries clear. Thumbs Up

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« Last Edit: Jan 17^th, 2018 at 6:34pm by Tom Coghill »

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robo_hippy

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Re: Too dry??
Reply #7 - Jan 17^th, 2018 at 9:41pm

Kiln/kill dried wood does not cut at all like air, solar kiln, or vacuum kiln dried woods. Rip a KD board on your table saw and you get dust. Rip any of the others and you get shavings. I have also found that if I rip an 8/4 board on the bandsaw so I can book match it, I get no spring, cupping or twisting to the halves at all.

Then, there is palm..... I had a friend give me a piece once, and I never forgave him.... End grain, it does okay...

robo hippy

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Lee Watermann Senior Member Offline WR Rocks! Posts: 416	Re: Too dry?? Reply #8 - Jan 17^th, 2018 at 11:21pm I ran into it on an old piece and the only way I could work it was with a scraper.
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Ralph Fahringer WR Addict Offline I'm the "Burly" Man!! Posts: 1,629 Ellsworth Maine USA Gender: PM3520b	Re: Too dry?? Reply #9 - Jan 18^th, 2018 at 10:05am A friend of mine gave me a couple of chestnut boards that are at least 100 yrs old from an old barn on his property. Think i might have a problem with these boards??
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Al Wasser WR Addict Offline WR Rocks! Posts: 626 Pueblo West, CO Colorado USA Gender: Robust American Beauty	Re: Too dry?? Reply #10 - Jan 22^nd, 2018 at 2:20pm I have some 2X4 material that is ponderosa pine. I was removed from a building that was built in the late 1800s in northern Arizona. I use it for a variety of things but it cuts and works just fine. yes it is dry but not too dry
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Leo De Bruin

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Re: Too dry??
Reply #11 - Jan 28^th, 2018 at 12:24am

Update
Thanx all for the input!

So it has been a learning experience! The dry wood has made me change a few things:

1)I am now monitoring the wood I bring into the house. 9 - 10% and it goes back out to the shop. Wood I have had in shop for a couple of years is usually around 10%

2) I started using a 3/8 DT v bowl gouge for final cuts before using NRS. I typically would just use my Ellsworth gouge for everything. Smaller finer cuts really help. This has also forced me to be more patient with my last cuts'

3) Still using oil for my last cuts and first bit of sanding

4) I will be checking MC of wood I have in shop and it should be picking up moisture out there. I can afford to wait for awhile before turning it.

Tom - thanx for reminding me about sanding sealer- I use Zinsser Seal coat but haven't used sanding sealer on the tearout for probably 10 years. I will get next time I am in town or order from LV. WB probably dries quicker than the Zinsser I am using

Thanx again guys

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