bowl roughing question

[david brum]

OK, so I'm roughing out 7 walnut bowls that I cut into blanks a few weeks ago. The first 5 went fine, but I noticed that number 6 started to show cracks along the outside of the bowl as I was shaping it. They go maybe 25% of the way into the side of the roughed out bowl (1/4") . This wood is not exactly green, but it is wet. As an utter, rank beginner at making bowls, I'm wondering if there is a way to save this bowl. If the cracks don't get deeper, I can still turn them down. Is there a way to prevent the cracks from going deeper? CA glue? Epoxy? duct tape?

I am trying to post a photo of the bowl. I sprayed water on the cracks before I wrapped them in brown paper. As I was taking the photo, I noticed that the cracks had closed....

Thanks in advance!

[Jonathan Harvey]

I'm sure many will disagree but I say embellish the crack. Make it bigger and then fill it with something like stone or coffee grinds.

Like they say if life gives you lemons make lemon aid.

[Steve Schlumpf]

David - couple of things... it has been my experience that once a bowl starts to crack - it is going to crack. You can coat the bowl, soak it, glue it or whatever - but it will continue to crack. Jonathan has a great suggestion of filling the crack once the bowl has been finish turned. You can highlight the crack or blend the crack in to the rest of the bowl - it is your choice and just another part of learning to turn bowls.

Other thing you mentioned was that you roughed out the bowl and the cracks went about 25% into the side of the bowl (1/4"). Are you saying the walls of the roughed out bowl are 1/4" or that the cracks run about 1/4" deep into walls that are 1" thick? Reason I ask is that a general rule of thumb when roughing is to leave the walls 10% of the diameter of the bowl. This gives you enough wood to turn the bowl round again once it has dried.

Hope this helps....

[Bernie Weishapl]

David I always, like Steve said leave my bowls about 1" thick when roughing. If they start to crack like yours is I soak with thin CA well past the cracks. This seems to stop most of them. After it dries I then DNA soak.

[Harvey Ghesser]

Bernie et all.... I need clarification please. I'm new to woodturning as well. When you say to soak in CA, are you saying to just add thin CA (cyanoacrylate) to the areas that are cracked? I guess I'm confused by the word "soak".

Thank you for any advise!

Harv

[Richard Madison]

David,
If I understand correctly, you say that on one bowl you sprayed water on the outside, the cracks closed, and you wrapped the bowl to allow it to dry. Suggest that you not add anything to the cracks in that one until after it is completely dry. You may find that when the piece is completely dry there are no cracks. If still cracked, that would be the time to CA, fill, or whatever the treatment of choice.

When roughing wet or damp wood it is sometimes helpful to keep the outside wet or moist while you are turning the inside. Oak, in particular, will begin to crack as you stand there looking at it.

[Reed Gray]

For me, cracks never go away, and almost always get bigger. I have noticed that trees/logs that have been down for a year or two will crack sooner than fresh green wood. As far as the cracks appearing while you are turning, I don't really know how they appear. If you have a halide light close to the wood, it can generate enough heat to cause those shallow checks, kind of like from getting too much heat while sanding. Most of the time, I will put cracked bowls in my factory reject box which I usually dispose of at one particular show I go to. From a production point of view, it isn't worth the time and effort to fill the cracks, and cracked bowls are much slower to go, even if I lower the price. I only do crack repair on special pieces.
robo hippy

[david brum]

Wow, thanks for the response guys. To clarify, the bowl is around 11" in diameter and I left it about one inch thick. The cracks go about 25% if the way into the wood.

Thanks for all the advice. I'll monitor the bowl over the next week or so. If the cracks don't open more, great. I'll turn it down to a 10 1/4" diameter bowl. If they do, I will definitely try embelishing the crack. Even though I only have an hour and a few bucks into the bowl, it still seems precious.

After I get the other two bowls roughed, I'm going to try DNA soaking. After that, I have a million questions about wall thickness, finishing, etc.

Thanks again

[Tom Storey]

You are probably keeping your gouges sharp, arn't you? I've heard that dull tools will produce enough heat when being forced to cut that the wood will sometimes crack When in doubt, sharpen

Tom

[david brum]

You are probably keeping your gouges sharp, arn't you? I've heard that dull tools will produce enough heat when being forced to cut that the wood will sometimes crack When in doubt, sharpen.

Good question Tom. I'm sharpening as soon as the shavings start getting dusty, probably 3 times for the outside and 3 times for the inside. Nothing feels hot, but what do I know?

[David Peebles]

Hi David,

I see from the pic you posted that there is a lot of sapwood vs heartwood in the bowl blank. In my experience this can cause a lot of tension in the wood. They seem to dry/cure at a totally different rate.

I think you can wait and see what happens over the drying period. But I find these usually end up in the BTU recycling bin in my shop... aka Wood stove.

But it is all good, experience is always the best teacher. And after all, this stuff does grow on trees.

Good luck,

Dave

[Dan Forman]

I'm just getting started with bowls too, and all 3 of my walnut bowls so far have cracked, the last one, like yours, before the rough turn was completed. Cracks were all in a similar area, near the rim. All had been cut last year and sat outside I untreated until I got them a couple of weeks ago. I don't know if that was a factor or not, as I have nothing to compare to. Like yours, I would describe the wood as damp (enough to mold), but not wet.

Dan

[Jeff Nicol]

Well here is what I have seen over the years with walnut. If the tree was down for over a year the bark will start to release and fall off. This let air directly to the out sapwood and it will start to dry faster especially the part of the log that will get the most sunlight as it lays in the yard. The wood will start to crack down radial lines and when you turn it they will appear. The part of the log that was on the ground may have some rot but will not do this as the moisture is greater there. But I would do just as Bernie said. Drip some thin/medium CA in the cracks and let it soak in and then do whatever you do to complete the drying: DNA soak, Anchor seal, paper bag and shavings or wahtever. The CA will stop the crack from continuing or slow it greatly so when you finish turn it the crack will be a thin line and easily stabilized with CA again in the finishing stage. Good luck and don't give up!

Jeff

[david brum]

I see from the pic you posted that there is a lot of sapwood vs heartwood in the bowl blank.

David,
I got the wood from one of my buddies, who is a sawyer. He said that lots of sapwood is very common here in the Pac NW (for walnut). The sapwood definitely behaves differently while turning. It seems like the heartwood holds more water and dulls the lathe tools faster. I can see how it would dry at a different rate.



Like yours, I would describe the wood as damp (enough to mold), but not wet.

Exactly Dan, my blanks got a bloom of mold after a few days. They also made an impressive mess of the inside of my bandsaw.



But I would do just as Bernie said. Drip some thin/medium CA in the cracks and let it soak in and then do whatever you do to complete the drying: DNA soak, Anchor seal, paper bag and shavings or wahtever. The CA will stop the crack from continuing or slow it greatly so when you finish turn it the crack will be a thin line and easily stabilized with CA again in the finishing stage.

OK Jeff. I'll pick up some CA glue and give it a try.

Thanks again, all.

[Kim Ford]

Dave;

Walnut can be fun when it is semi-green. A construction company my daughter works for in Kentucky gave me several hardwood logs from a clearing they were doing which included a walnut log that hand been felled over a year earlier. I roughed out about ten blanks 12-14" in diameter with about 1" walls, and thought I hit the mother load.
I baged them with some shavings from the log and thought everything would be well. Fortunately, my daughter called and asked if I could turn one green so she could give it to her supervisor as a thank you. This was a day or two after I had bagged them, so I picked one of the bags and opened it up to turn a green bowl, and the cracks you described were everywhere. I opened all the bags and all were the same.
I keep several large trash cans in my shop that I put the shavings in and they were still there from the roughing out exercise and pretty much full of walnut shavings. I immediately buried the blanks down in the shavings in various cans, and old trick that works well, and started experimenting.
The best results were the blanks that I put back on the lathe and turned out the cracks, (about 1/8" on each side), and then put back in the shavings for a couple of days, and then did it again and again. Yes they did warp a little and when the blank reached the point that I knew I did not have enough wall thickness to go another cycle, I finished them off, sanded (don't let heat build up or you get more cracks), and polished. I then took them to the microwave and did the Raffan trick with the microwave. The finished product was really quite nice for a green turned bowl with wall thickness of about 5/16".
I've would now probably try the anchor seal coating process on the green blanks because it has been successful on other green woods but at the time I wasn't doing it.
Good Luck.