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The Pith

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Or should I say evil pith. I know you want to avoid the pith. I had a small elm about 8" down that had been on the firewood pile for a year and noticed very little cracking around the pith. Just for practice turning hollow forms I turned two pieces, one pith to pith and one through the pith. Just some minor cracking around the pith after 4 months finished.

So are there woods that you can leave the pith? I've heard NIP is one. Does anyone remove and plug the pith (thinking hollow forms and not bowls). Are there treatment for leaving the pith?

Here is a vase turned for practice ( and some small bowls) I was practicing. The cracking extension out some what, but seem to be stable. Some would not want any cracking, but some it would be "character".

Opinions?


IMG_0461.JPG
 

odie

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Nice job of it, Wm......:D

You got away with it, and ended up with a nice vase. For myself, I avoid the pith like the plague! In times past, I did try to incorporate the pith into turnings, just for character and interest sake, but I've had more failures than successes with it. I just avoid it now......not worth the gamble.

This is one of my few successes......
Walnut Natural Edge #653.jpg
Sorry about the bad photography.......was awhile ago! :oops:

-----odie-----
 

hockenbery

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I leave pith in some greenwood turnings.
If it is turned thin with curve it will dry without cracking most of the time since the wood can move.
Often some woods wil
Each want to dry to a smaller diameter than the rim side it. So something has to give.
Turned thin with a curve allows the drying to telescope out as the rings dry by pushing the one inside outward.


One issue here is that bump will distort the curve of the piece.
Smaller diameter logs will be more successful.

A bowl like Kelly showed will often work since the bottom bumps out in the curve so distortion is less obvious and the curvature allow the rings to push the inside ones out.
 
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john lucas

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Several people have done wonderful hollow forms with the pith in the base, removing it a plugging. If you remove the pith and dry it very very slowly it is less likely to crack. What I did was cut off that portion of the base and dried the pith by putting it in a plastic bag and turning inside out every day for about 3 months. It was about 3/8" thick. Don't remember the species off hand. I then hollowed the vessel and drilled through the pith that remained. After it dried and the pith piece dried I trued up the drilled hole and then carved the pith plug to fit. You could barely see it once I got it all sanded and finished. learned that from John Jordan.
 

hockenbery

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Here are two NE bowls in progress.
Both have some spalting so the wood will be less likely to crack.
Both are sanded to 320 except of the rim. No finish.

This one is red bay It doesn’t show well but the two bumps at the pith make the curve funky.
33FE8BE0-3791-4A95-A624-0FB189ADB8C6.jpeg 3E75E84A-E914-4201-8C1D-472ADC717831.jpeg

This one is citrus three piths. I haven’t worked on the rim yet.
45269363-5787-4F94-8205-7538E8DF71E3.jpeg
 
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Have not done a lot with pith in as I try to avoid it. I did have success with 2 methods.
1. drill out the pith with small drill bit and use a contrasting or similar wood dowel to plug
2. drill out and use colored epoxy.
Preferable to use 1/4" or less drill. If in the bottom of a hollow form the fix will be almost not be noticeable.
 

RichColvin

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I like mixing the heart and pith when turning cedar or juniper. In particular, I like to turn it with the grain going parallel to the bed, and I've found that by selectively picking where I transition from the pith to the heart, the piece can look like it's fire (if you look hard and turn your head to the side in just the right way ...).
 
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I have done a bunch of natural edged branch vase forms, pith intact.
The greatest success was with a 'turned in one session', consistent thin wall, off setting the pith from the center of the base and slow drying.
Pith on the rim of a bowl...not much luck.
I prefer not to use fillers or ca. Warping is to be expected, pieces with bad cracks end up in the 'what not to do next' pile
 
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surprised no one mentioned this wood
 

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hockenbery

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NE goblets and vases are forms that work well with the pith in the bowl.
As Mark mentioned.
The curvature in the bottom let’s the pith squeeze the rings outward rather than crack.
If the pith is in the stem it will be weak and likely break.

A Holley vase. Apologies or the poor photo

92D6D882-0E0A-4CEC-884E-FF4D0E97BC3D.jpeg
 
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I thought that it was common knowledge that everyone knows about mesquite. :D
All I know, is if you add an "O" to the end of mesquite, it's likely to bite you. The mesquite-o-s don't even care if I'm wearing a face guard. I think they could even get under the neck of a turner's smock! Not that I own a smock...that's what the beard is for.
 

Bill Boehme

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no 1stand experience....but I have read that it only takes 2 mesquit-oes to carry a gold miners mule off with all his gear

When we were in Alaska on vacation, I thought that I saw a swarm of helicopters, but I was told that they were mosquitos. :D Mesquite is much nicer.
 
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NE goblets and vases are forms that work well with the pith in the bowl.
As Mark mentioned.
The curvature in the bottom let’s the pith squeeze the rings outward rather than crack.
If the pith is in the stem it will be weak and likely break.

A Holley vase. Apologies or the poor photo

View attachment 23836
Thanks Al, I am away from home and didn't have a good picture.
 

john lucas

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Dave Barriger was the one who taught me that if you turned a cone shaped piece with the pith in the bottom it wouldn't crack. When the wood dries and shrinks the cone gets smaller and longer. The ability for the wood to move freely is what keeps the wood from cracking. I think Dave was doing the the tall vases on a wooden spring back in those days.
 
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Dave Barriger was the one who taught me that if you turned a cone shaped piece with the pith in the bottom it wouldn't crack. When the wood dries and shrinks the cone gets smaller and longer. The ability for the wood to move freely is what keeps the wood from cracking. I think Dave was doing the the tall vases on a wooden spring back in those days.

Since I don't know, what is the orientation of the cone?
 

hockenbery

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Pointy bottom to the form
Similar to the shape of the vase I posted above. While the pith in the case is slightly off center the shape allow the outside rings to push the inside rings outward as them wood dries.

The issue with pith cracking is that a that the wood shrinks more around the rings than it does across the rings.
So each ring wants to shrink to a smaller diameter than the ring inside it shrinks. This usually causes the pith to crack.
 
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I have done a bunch of natural edged branch vase forms, pith intact.
The greatest success was with a 'turned in one session', consistent thin wall, off setting the pith from the center of the base and slow drying.
Pith on the rim of a bowl...not much luck.
I prefer not to use fillers or ca. Warping is to be expected, pieces with bad cracks end up in the 'what not to do next' pile


Mark,
I am working my way through a pile of logs that I want to turn using the length of the log and leaving the pith intact. Can you offer some insights beyond the extent of your post, how you have increased your odds of success?
Thanks,
Ed W
 

hockenbery

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Best forms for keeping the pith are fairly thin walled with a curve.
When wood dries the each growth ring will dry to a slightly smaller diameter than the growth ring Inside it.
To dry without cracking the inside growth ring has to push out like an expanding camp cup.
Thin wall and curve promote the pushing out.

I will add a few photos later. I have had success with are endgrain goblets, endgrain vases, hollow forms, and natural edge bowls.
 
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And then there's David Ellsworth. He makes thin walled hollow forms with the pith in places you'd never imagine. His thoughts are that if it cracks, it cracks. He sees it as what the wood wants to be and that suits him just fine. And, for the record, his work is magnificent, pith, cracks and all.

Most of us don't care for that sort of silliness; no offense Dave. Typically I cut the pith out with a chain saw when I harvest a log. Easy enough to do then. The trick, often, is keeping some of the colored wood around the pith but not so much that it cracks. So I get the piece turned, sealed in Anchor Seal and stuck in a paper bag for a couple months. Get about 75% success that way and the pieces are a lot prettier with colored grain running through them.

Not sure how I'd approach the plug idea, but it shouldn't be too difficult. Having the growth rings showing would be interesting. I've got some logs lying on the ground right now that would be the right size for such a stunt. Thanks for the idea.

And the pieces you showed were very nice. Even if there are some pith cracks, they have an edginess to them such that a minor crack adds to their loveliness.

Jerry
 

hockenbery

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I think every turner who reaches the advanced skill level should turn at least one natural edge goblet just because they are fun to do.

Some pithin for photos
Naturaledge holly Vase shown earlier 32B6117B-299E-41A2-AF13-A6E2C5682628.jpeg Natural Edge oak goblet 2A724C60-C7CE-48B8-A870-1CDED25336E8.jpeg pith should not be in the stem for either so find a log that has the pith off center 18B62E2A-24D5-4FB0-9626-2AFA0E94F37C.jpeg

Natural edge elm bowl7447DF33-9422-4F9C-994E-B1CA4AEF8486.jpeg The bump where it dries goofs up the curveD5DAEECF-EF40-49D1-BEAB-44951C4E59B6.jpeg

Pith in citrus hollow form4942058A-892E-4C6C-9533-8F12E41A87A6.jpeg Sun petroglyph is over the pith
 
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What Bill was saying is what I have learned also, thin and curved then dry slowly and it will not split.

First time I had good results with my thoughts of giving the wood the option to change shape rather that split was with a about 14 inch bark on endgrain bowl, I let the sidewall stick out below the bottom and then turned the bottom in a slight curve, as the bowl dried the curve did dry down some more, but never split.

Since that time I have turned some more bowls that have piths from limbs in them, turned these bowls real thin the pith will not split but bulge out, like in this bowl.

Maple with pith.jpg Pith in Maple.jpg

The other thing I do is to fill the pith only, with CA while the wood is wet, and have a 99% success rate, here is an Ash bowl with 3 or 4 pith in knots, this crotch wood bowl also had a split in it while still growing, I did put CA in after rough turning it (picture 1 below) it all did work out nice, someone did like it enough to buy it :)

CA in rough turned bowl.jpg Finished bowl with knots.jpg
 
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Mark,
I am working my way through a pile of logs that I want to turn using the length of the log and leaving the pith intact. Can you offer some insights beyond the extent of your post, how you have increased your odds of success?
Thanks,
Ed W
Can't add much more than Al and others have posted.
Consistent thin wall, slow drying, off setting the pith from the center of the turning, don't allow the piece to sit partially turned for any length of time.
Be careful of too much heat buildup when sanding, some woods like cedar heat check very easily.
 
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Hé Charlie I call those pith splits, granted not very big, but that is probably because the tree was starving for water and so there is no shrinking when drying some more :p

View attachment 24905
could be Leo....when I turned that piece I purposely left the pith in the blank positioned where it is because I had heard that you could leave the pith in....I could have turnred a larger piece but I like a 6 or 7 inch wide piece for display.....at least for my display.....I understand others have opportunities to display much larger pieces
 

Emiliano Achaval

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Take a look at my gallery, maybe on my website. One of my best sellers is the Ku'oho calabash. Made from a big Kou or Koa crotch. So, you will have 3 piths there... I use the same solution that the Hawaiian used, lots of pewas... I have CA, that they didnt have back then, lol. Take a look at the Milo NE I posted here today, I left the pith, I used a pewa and a turtle to fix cracks in the pith. I see the pith as a design opportunity, and a way to enhanced the turning, adding repairs adds $, and my local customers love the pewas. A lot of them request them... I have, many times, added pewas even tough they were mot needed, lol
I do not see the pith as a problem, I see it as a way to enhanced a turning. That been said, I dont always use it... Some woods moves more than others, like macadamia, if you have a pith it's all over before you even started... Aloha.
 

Emiliano Achaval

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Nice job of it, Wm......:D

You got away with it, and ended up with a nice vase. For myself, I avoid the pith like the plague! In times past, I did try to incorporate the pith into turnings, just for character and interest sake, but I've had more failures than successes with it. I just avoid it now......not worth the gamble.

This is one of my few successes......
View attachment 23817
Sorry about the bad photography.......was awhile ago! :oops:

-----odie-----
Odie, take a look at a milo end grain platter I did, looks familiar? lolIMG_1098 2.jpg
 

Emiliano Achaval

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Several people have done wonderful hollow forms with the pith in the base, removing it a plugging. If you remove the pith and dry it very very slowly it is less likely to crack. What I did was cut off that portion of the base and dried the pith by putting it in a plastic bag and turning inside out every day for about 3 months. It was about 3/8" thick. Don't remember the species off hand. I then hollowed the vessel and drilled through the pith that remained. After it dried and the pith piece dried I trued up the drilled hole and then carved the pith plug to fit. You could barely see it once I got it all sanded and finished. learned that from John Jordan.
Talk about labor intensive.....
 
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Emiliano,
Okay, I'm taking your advice. I just won a medium sized Koa log on eBay and I'm certain there will be pith to deal with. I've got CA glue as well so I'll study it when the log arrives and make a decision. CA or a plug. More on this later.

On another note, I haven't forgotten I owe you two pieces of Maple. A friend of mine that's experienced at taking down trees will be visiting around early June and has told me that he'd be happy to help me take down TWO very large maples. Both of them are showing signs of rot high up so there's going to be good wood in the lower sections. I'll find a couple pieces suitable for you and send them to up country. I've taken down some smaller trees but didn't find much to suit you for the trade we made.

I'll be in touch.

Jerry
 

Emiliano Achaval

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Emiliano,
Okay, I'm taking your advice. I just won a medium sized Koa log on eBay and I'm certain there will be pith to deal with. I've got CA glue as well so I'll study it when the log arrives and make a decision. CA or a plug. More on this later.

On another note, I haven't forgotten I owe you two pieces of Maple. A friend of mine that's experienced at taking down trees will be visiting around early June and has told me that he'd be happy to help me take down TWO very large maples. Both of them are showing signs of rot high up so there's going to be good wood in the lower sections. I'll find a couple pieces suitable for you and send them to up country. I've taken down some smaller trees but didn't find much to suit you for the trade we made.

I'll be in touch.

Jerry
Hello Jerry! Do not worry, I know it's not easy to find a nice blank... Dont work too hard, cutting trees down is a lot of work!! Hope you will show us what you make with the Koa you won on Ebay!! Aloha
 
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are there woods that you can leave the pith?

Yes and NO. My first bowl was a honkin huge hunk o Maple. I left the pitth in cos I didn't know any better.
It has sat as a large 20 foot log in my yard for maybe 3 or 4 years before I cut it. no issues with the pith.
So it was mostly dry.
THAT is when you can use the Pith - - - DRY.

Elm Dries up really quickly and checks but with small easy to manage checks.
The dead opposite of Oak.
Of course it machines real well and has almost no spring in it.
those are among the reasons so many saddlers and coffin makers preferred it.
 
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Emiliano,
Just staying safe in the shop is a challenge sometimes. Got in a hurry on this one. The only thing I did RIGHT was to NOT stand directly behind the saw blade. If you never understood why you shouldn't, this should show you everything you ever wanted to know.

JerryOuch.JPG
 
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Emiliano,
Just staying safe in the shop is a challenge sometimes. Got in a hurry on this one. The only thing I did RIGHT was to NOT stand directly behind the saw blade. If you never understood why you shouldn't, this should show you everything you ever wanted to know.

JerryView attachment 25067

Use of CA to keep it there wasn’t necessary I assume :p

Bet you didn’t wear your face shield either :eek: :oops: ;)
 
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I had pulled a few pictures to show turnings with the pith in it that never split, but also that using CA in the pith and immediate area does affect the warping, reducing that through preventing the shrinking.

I have two similar large Elm turnings, where in the one I did add CA to the pith and area, and left the other one to shrink, showing the reduced amount of warping in the one with the CA in comparison with the one without any CA in it.

I forgot about posting it, (life gets in the way sometimes) anyway look at it and think about what can and does happen when wood shrinks and what if you add CA to the wood and in effect reduce or eliminate the shrinking and the effect on the rest of the turning.

Elm inside.jpg Large Elm.jpg Elm hat.jpg Warped Elm.jpg Very warped Elm.jpg

Another pith-in turning that has not split or warped,we still have this one.
Black Cherry.jpg Black Cherry profile.jpg Black Cherry base.jpg
 
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