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Crack repair question

K

Kirk Witmer

Joined
Sep 12, 2022
Messages
28
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13
Location
Tyrone, PA
Hey just working on an oak bowl for a customer and have a question about a crack. The crack is about 3” long and about 1/4” at the widest point (yes I know it’s a huge crack) just wondering if there’s as way to hide it pretty well, normally I would put black or brown epoxy in for contrast. Just wanted to see if anyone has a good way to hide it.3715C1D4-9482-46A8-B810-C20A2E5D3D5B.jpeg5DA8FC63-3FE2-44E1-BE1B-53645638A918.jpeg
 
Nah, it’s just takes some time, the smaller ones can be filled with sawdust and wood glue, and if done correctly the become almost invisible. Turn a wood bowl does a video on it.
 
No. Cracks, even filled, are still cracks. And depending on the environment, they can still open up after filling. I would walk away from that piece and start with another. To quote a well-known turner who recently passed, "Life is too short to turn crappy wood". John Jordan.
 
You aren't going to hide a 1/4" crack. You can accent it or fill it but can't hide it. Fill it with epoxy, add a couple butterflies, or drill holes on both sides and stitch it together with wire or leather.

IMO lots of ways to accent the large crack, but the smaller ones, even filled with sawdust, are always going to look like cracks.

Don't know what the customer wants, but I'd choose another blank.
 
Also, I think a possibility of a better choice of location of the blank - your rim being so very close to the pith, no wonder there's cracking.. I do not believe I have *ever* successfully twice turned a piece that the rim was that close to the pith without having to cut away a very large portion (I'd say at least 7 to 8 rings worth in your blank) away from the pith... You could possibly cut away a sizable portion of the rim (smaller bowl would result) and allow some more drying time , the cracks *sometimes* , in *some woods* may close up by themselves , but they'll still be visibly cracks, even if they completely close up to where you can just wick in some thin CA glue.

But, if it was me, seeing the worm hole in the side, and the cracks through the bottom (and into the tenon) I'd most likely toss that blank in the firewood pile and try again. If it was "green" un-dried wood, I'd say 2 months wait time is not enough - I will usually quote a 4 to 6 month lead time at a minimum on a twice turned bowl when the customer brings me the log (assuming, that is, the log is even worthy in my judgment) , so many casual customers that just bring me the wood for the heck of it, will tend to pick a natural edge once-turned bowl instead (which can be just a few days out, with their understanding that the bowl IS going to warp and move over time.)
 
What was your plan to remove that steel stain in the bottom? Use something besides steel as your friction drive. You're lucky that bowl didn't hill you. Looks like that larvae is still in there! I agree with Brian, that's firewood. 2 months is a long turn around for a small bowl. Maybe that's why you got the cracking.
 
You’re being offered some wisdom in these responses. I’ll add one thought. I’m, thankfully, not dependent on my turning to feed my family. I do however get pleasure out of both giving away and selling what I turn. Therefore, I try really hard to not turn custom orders, but rather turn “on spec.” In other words, turn what you like and offer it for sale. If someone likes your work, they’ll buy it. Whenever I’ve accepted a commission, I usually (not always, but usually) enjoy the process less than when I’m turning what I like. As you get more experience and skills, this will change, and you’ll be confident that you can produce what you want to. You’ll also understand better the characteristics of the imperfect, but wonderful material we turn.
Finally as Al said, if I’m using a piece of wood from someone’s tree and it was green, I tell them it’ll take six to twelve months to dry before I can turn a twice-turned bowl from it. They may initially be disappointed, but they’ll be thrilled when you finally come back to them.
 
If it were mine it would definitely be a sacrifice to the pizza gods (I have a wood fired pizza oven to keep fed). With rare exceptions, repaired cracks in pieces simply look like mistakes that have been patched. Those pieces that succeed were, I suspect, designed around the imperfections, not created in response to an unpleasant surprise.
If you often do work for customers on demand it's good to have a good supply of roughed out bowls drying on a shelf somewhere. Do a couple every week and soon you'll have a hundred ready to finish turn on a moment's notice.
 
Richard Coers said:
What was your plan to remove that steel stain in the bottom? Use something besides steel as your friction drive. You're lucky that bowl didn't hill you. Looks like that larvae is still in there! I agree with Brian, that's firewood. 2 months is a long turn around for a small bowl. Maybe that's why you got the cracking.
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It’s actually not a steel stain, and the bowl is still about an inch thick there. So I would just turn it away, I use a chuck to hollow my bowls. I think the stain is a little bit of mold. It turned that color while it was drying .
 
If this were a piece I was just turning from stock for possible sale I'd pitch it. Oak is very common here and I usually have more of it than I care to work with. If it was a piece of a tree that meant something to someone then I'd give them options of a color fill with caveats re stability over time. My motto re cracks, knots and holes is hide so that only you know where it is and no one's eye will be drawn to it, accept it as character (don't think an option here), or accent it with fill of some color that adds character and appeal. Not always possible but an option.
 
Kirk Witmer said:
It’s actually not a steel stain, and the bowl is still about an inch thick there. So I would just turn it away, I use a chuck to hollow my bowls. I think the stain is a little bit of mold. It turned that color while it was drying .
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That is tannic acid it is typical when working with oak your fingers will become blackened from it.
 
Kirk Witmer said:
It’s actually not a steel stain, and the bowl is still about an inch thick there. So I would just turn it away, I use a chuck to hollow my bowls. I think the stain is a little bit of mold. It turned that color while it was drying .
Click to expand...
As Don mentioned above- Tannic acid in the wood (Oak is rich in tannins) reacts with many metals (and salts - I've turned nicely sanded boards black in spots where I leaned on them during the summer, due to sweat on my arms reacting with tannin in the oak) and had to then run them through the planer again and re-sand - learned my lesson there so during sweaty work, I take extra care not to get sweaty arms (or drops of sweat from forehead) on the wood.
 
Brian Gustin said:
As Don mentioned above- Tannic acid in the wood (Oak is rich in tannins) reacts with many metals (and salts - I've turned nicely sanded boards black in spots where I leaned on them during the summer, due to sweat on my arms reacting with tannin in the oak) and had to then run them through the planer again and re-sand - learned my lesson there so during sweaty work, I take extra care not to get sweaty arms (or drops of sweat from forehead) on the wood.
Click to expand...
In addition to Brian's comment I have turned green red oak and as it dries black spots appear on the surface especially in thin once turned pieces.
 
One like that, for me, goes for a 'garden' bowl, for bringing in stuff from the garden, or scooping out bird feed. You can repair it just for a 'learning' experience, but not worth the effort for me.

robo hippy
 
I would not trust a Pewa or a few of them to finish turning it. I only advice using pewas if the crack is not compromising the bowl structurally. I would use a large poho patch here. Mark Stebbins made 3 prototype sizes for me and they work great.
 
You sent me back to my favorite reference book: UNDERSTANDING WOOD by Bruce Hoadley.
Red oak has a green to dry tangential shrinkage of 8.9% and a radial of 4.2% (p. 74). To my thinking it's a lousy wood for turning and a super lousy wood for turning bowls.
The only piece I've done is a 20" hollow-form commission piece - after roughing to 1.25" thick, I boiled it for about 3-hours and then did a controlled / slow dry for 10-months before final turn - the log was 4'-diameter and the pith was not close to the part I turned. While the piece came out good, I'll avoid red oak for anything other than an occasional weed-pot (where cracks are cool).
And finishing was no day in the park. That's the beauty of weed-pots - a little gel finish and good-to-go
 
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