Bowl wall thickness

[Dean Center]

I have a topic that I hope will produce some interesting discussion, as I don't believe there is a right and a wrong to the query. Maybe some of the lurkers who don't comment often will want to chime in on this one.

I have recently been reading Richard Raffan's book "Turned Bowl Design," in which he demonstrates an extensive amount of observation and thoughtful consideration of the topic. I can only read a half dozen pages a day to keep my head from exploding with all the thinking he stirs up.

In one part of the book, he shows photos of bowls which he has cut in half to illustrate points about wall thickness. He states his opinion that the wall of the bowl should NOT be a uniform thickness over it's entire course. His ideal wall is a little thicker near the rim and a little thinner in the transition zone in order for the bowl to FEEL properly balanced. A bowl with a uniform wall thickness inherently FEELS bottom heavy and awkward to Richard.

Our local great mentor and Montana's best turner ever, the late Gordon McMullen, taught me that a uniform wall thickness was the mark of a good craftsman. I've heard a gallery manager who showed his work comment that his bowls were the best, BECAUSE his walls were always a uniform thickness.

In the experience and opinion of this broad community of turners, what are your thoughts on wall thickness? Uniform or Raffanesque? Or something else? Thanks for sharing.

 

[Gerald Lawrence]

Ashley Harwood expressed the same thought on bowl design and explained that it made it easier to pick the bowl up by the rim.

 

[hockenbery]

I have discussed wall thickness with lots of really good turners and lots of students.
There are many answers all correct. But some answers are better than others.

First - sort of ancillary to your question - for drying rough turned bowls an even wall thickness or close to it is best for preventing cracks.

Talking about walls must be done in the context of the bowl

I like even walls for thin walled bowls less than 3/16” and most natural edge bowls.

I have a preference for uneven walls in cut rim bowls with the wall getting thinner below the rim. These often look better to me than those with even walls. They also hold a tiny bit more soup. And they often feel better too.

I usually don’t like the look or feel of bowls whose walls get thicker toward the bottom.

However there are some designs where the inside is a pleasing curve inside while the outside is a complex of curves and flats so that the wall thickness varies all over with the outside contour.

Bowls with holes in them natural or made usually look better with even walls.

Following the rules for bowl walls produces good looking bowls
Breaking the rules produces a lot of dogs and an occasional great bowl.

 

[Zach LaPerriere]

I'm with Raffan on this. I think uniform thickness is a good aim—we should all be able to pull it off. But a little thinner as Raffan describes just feels better in my opinion. Cut some bowls in half, and you see the difference, and it also looks better in my opinion—provided the proportions are right. It is easy to have the rim a bit too fat too high then put the thinner section too low. This both feels and (when cut) looks ridiculous.

I've gotten flack for siding with Raffan by some talented turners. You'd think there was an 11th Commandment! But on the other hand I've also gotten some compliments from people I equally respect that say those proportions feel better.

In talking with ceramics folks, I've usually heard that proper weighting is superior to uniform walls. And when breaking my favorite ceramic bowls (courtesy of my all thumbs and the occasional young son) I agree.

Structurally: it also just makes sense to me, though it could also be argued that a thinner bottom also makes structural sense.

Finally: a while ago, I tried even thickness on a few bowls, then rechucked and shaved a little in what I thought were the right places. I preferred the paired down bowls.

And that leads to one more thought...if anything, I would lean toward having the walls a little thinner at the transition zone as describer, not the reverse: everything else a touch thicker.

 

[Odie]

Interesting discussion......and, when contemplating wall thickness, most of us have been there, and done that! For quite a long time, I was doing thin-wall bowls with uniform thickness. That is, until I concluded that nobody really cares, except a few other turners who are bound by self-imposed rules! I do agree that it takes great skill to turn a well made thin-wall bowl, but I really don't care anymore.....with the exception that a bowl can be too heavy, and should have had thinner walls. I don't make many salad bowls, but lately I've been making them with extra thick walls. (The intent here is to have a salad bowl that is tough as nails, and will survive many years of heavy use, and abuse.....utilitarian, rather than aesthetic.) For bowls that are strictly decorative, and maybe slightly useful, I now tend to side with Raffan. I don't consider uniform thickness with much regard anymore, and concentrate more on how it looks and feels.

I suspect many turners turn to conform to what others think is proper, rather than allowing their own self motivations thrive.....

-----odie-----

 

[Fadi Zeidan]

I was watching a demo, I believe it was Glen Lucas, where he said having thicker rim gives the bowl sturdy and heavy feel to it, yet when you lift it feels lighter than it looks. That made sense, if the transition from thick to thin done right, handlers shouldn’t notice the difference and no one going to take a finished bowl to a bandsaw.

 

[Don Wattenhofer]

I have discussed wall thickness with lots of really good turners and lots of students.
There are many answers all correct. But some answers are better than others.

First - sort of ancillary to your question - for drying rough turned bowls an even wall thickness or close to it is best for preventing cracks.

Talking about walls must be done in the context of the bowl

I like even walls for thin walled bowls less than 3/16” and most natural edge bowls.

I have a preference for uneven walls in cut rim bowls with the wall getting thinner below the rim. These often look better to me than those with even walls. They also hold a tiny bit more soup. And they often feel better too.

I usually don’t like the look or feel of bowls whose walls get thicker toward the bottom.

However there are some designs where the inside is a pleasing curve inside while the outside is a complex of curves and flats so that the wall thickness varies all over with the outside contour.

Bowls with holes in them natural or made usually look better with even walls.

Following the rules for bowl walls produces good looking bowls
Breaking the rules produces a lot of dogs and an occasional great bowl.

I think this is the most balanced reply the only thing I might add is the inside and outside curves should be close the identical other than the rim and foot.

 

[Odie]

Related comment about thin wall bowls: Just as a bowl can seem too heavy and bulky, the opposite is true with many thin wall bowls. They can seem too light and delicate. Light and delicate, in itself, isn't necessarily undesirable, but in some cases, it definitely can be. It all depends on any one's individual perception. What seems too light or heavy for one person, isn't necessarily indicative of all observers.

Another aspect of thin wall bowls, is structural integrity is at a greater risk when there isn't much mass, or volume of material left to resist internal stresses. Not all examples will warp during the act of turning, but some do. If a turner isn't ready for sanding at the point where it begins to warp, then there is little chance that the surface can be improved with additional tool work. Tool work can only respond well to geometric integrity....or, the closer to a perfect circle is the circumference, the likelihood tools can improve the surface is greater. It all depends on how skillful a turner is......and, that is one very big consideration. The more out-of-round the surface is just increases the need for aggressive sanding.

-----odie-----

 

[hockenbery]

You can always sand off the lathe.

 

[Odie]

You can always sand off the lathe.

You've missed the point here, Al......if you want details that are crisp and distinct, then the only way to do that is with exceptional tool work, combined with geometric integrity......but, you are correct that sanding can save a warped bowl, on or off the lathe. Thin wall bowls are more prone to warping, but not necessarily in every case.....


Embellishment can save a bowl with poor tool work, and we see that all the time!

-----odie-----

 

[hockenbery]

but, you are correct that sanding can save a warped bowl, on or off the lathe. Thin wall bowls are more prone to warping, but not necessarily in every case.....


Embellishment can save a bowl with poor tool work, and we see that all the time!

Sanding off the lathe is virtually impossible without good tool work.
My HF &NE bowls will warp as they dry. A nice shear scrapped surface is easy to sand.

Embellishment varies a great deal.
Not sure what embellishment techniques you use to save poor tool work

Most embellishment techniques require superior tool work and a finished surface before the embellishment begins.
Sand carving, carving, piercing, basket illusion, pyrography, airbrushing, spirit stains, milk paints all start with well turned and usually sanded surface and sometimes a finished surface.
Little parts of the surface will show poor turning

 

[Emiliano Achaval]

Sanding off the lathe is virtually impossible without good tool work.
My HF &NE bowls will warp as they dry. A nice shear scrapped surface is easy to sand.

Embellishment varies a great deal.
Not sure what embellishment techniques you use to save poor tool work

Most embellishment techniques require superior tool work and a finished surface before the embellishment begins.
Sand carving, carving, piercing, basket illusion, pyrography, airbrushing, spirit stains, milk paints all start with well turned and usually sanded surface and sometimes a finished surface.
Little parts of the surface will show poor turning

I have to agree with Al. I like to start with a good surface to do embellishment. It's also a matter of pride, every piece that I make, I try my best. If you try to embellish over a bad surface, I can probably see the tools marks below the attempt at hiding them... I try to make an even wall, I use my Thompkins gauge whenever possible, I remember Raffan saying his fingers are his calipers, I do that often, but the Thompkins gauge showed me how wrong I can be!

 

[john lucas]

It's been my experience you can rarely save a bad piece by embellishment. Form is particularly critical. On rare occasions you can texture something to keep from sanding but only if you have good tool work to get to that point.