Another Design Discussion

[Noah Peters]

I have recently started to draw bowl designs on paper to refine shapes or thrash out ideas before I go to the lathe. I was inspired to start doing this by Derek Hayes book Woodturning design and by Mark Wardle's drawing videos. It has also drawn me to look at ceramic bowls for inspiration and ideas. In doing this I have started to notice some big differences between the rules of thumb I follow and what is seems to be used in ceramic bowls. The first biggest are that ceramic bowls seem to have bases closer to 50% of the diameter rather than the 1/3 diameter I have been using for wooden bowls. The Second is, from what I have seen, ceramic bowls have a sharp curve change near the bottom leading to a flat interior. Flat interior bowl bottoms and curve changes on wooden bowls seems to be frowned upon, so I have avoided it seeking rather for a smooth curve throughout.
I do agree that a smooth curve throughout feels wonderful, so why do not all ceramic bowls have this? Not all of the ones I have are like this, some do have a continuous curve and are nice pieces. They do still have a large foot though. In looking at some eating bowls from Robin Woods book, some of the bowls in it also have this curve change with a flatter interior. Is this a utilitarian choice or is there and way to do this with the piece's artistic value intact?
I am curious as to what others may think on this matter and what rules of thumb are generally used and how they go about doing it.

 

[Odie]

Bowls exist to be utilitarian. I think that, generally, ceramic bowls with a larger foot are intended for utilitarian uses, such as dinnerware. This makes sense when you consider stability is greater with a larger foot. When a bowl shape moves away from utilitarian concerns, into the realm of artistically desired outcomes, that is the point where utilitarianism begins to take a lesser priority. Unlike some of the rules common to woodturners, the 1/3 rule is a good one, and leads to more graceful and appealing shapes, at the expense of stability. That said, you can still make a dog bowl that fits the 1/3 rule......so, it takes more than the 1/3 rule to make a pleasing shape!

When you rough out a twice turned bowl, you are creating the boundaries by which to work within......and, this is why the roughing stage is an important part of the overall design process. This is the point where you have to have some idea of what the final shape will take, as well as eliminating or accentuating physical aspects or flaws in the wood itself. For me, the roughing stage has evolved to certain elements that fit the "style" I have evolved to......but, the 1/3 rule remains a staple of my style.

-----odie-----

 

[john lucas]

Get zrichar Raffen's book on bowl design. Has some fun ideas.

 

[JeffSmith]

Personally, I haven't noticed ceramic bowls having flat bottoms and larger feet...as I look at our collection of utilitarian pieces and display pieces (with the exception of platters) I find quite the opposite.
Open form bowls with a continuous curve to the bottom are easier, more ergonomic to use and require a smaller foot for the same stability. More mass down low concentrated towards the center. The bowls I turn follow this more often than not, so I suppose I'm predisposed to generating this form.
The classic dog dish with a flat bottom will require a larger foot to avoid tipping.

 

[Noah Peters]

Personally, I haven't noticed ceramic bowls having flat bottoms and larger feet...as I look at our collection of utilitarian pieces and display pieces (with the exception of platters) I find quite the opposite.
Open form bowls with a continuous curve to the bottom are easier, more ergonomic to use and require a smaller foot for the same stability. More mass down low concentrated towards the center. The bowls I turn follow this more often than not, so I suppose I'm predisposed to generating this form.
The classic dog dish with a flat bottom will require a larger foot to avoid tipping.

Most of the ceramic pieces I have access to regularly have the flat bottom but they are not handmade pieces either. The ones I own that do have curved interiors are handmade, but they still have a wider base.
Having the mass lower to create stability is not something I have thought of using before, beyond rounded base bowls, and will need to look into it.
It is cool to see that you have noticed the opposite of what I have seen and that shows just what a small selection of pieces I have actually viewed.

 

[stu senator]

I don't do ceramics but with the 1/2 rule and flat bottom be an effort to keep a uniform wall thickness to prevent problems during firing?
Stu

 

[Dean Center]

When you think about how potters go about making a bowl on a wheel, they start with a lump on the center of the wheel, molding it with their hands. Regarding the shape, think about wet, flexible clay getting drawn out away from the base, thinner and thinner. Pretty soon there's not enough strength in the lower section to support the upper, and splot! One solution would be to draw the walls up more vertically. Another would be to have more thickness in the lower areas, which would produce a heavier overall, but especially bottom heavy, finished bowl.

If the ceramic bowls you're seeing have 50% bases, probably your local potters feel the need for that much of a base for some reason. Maybe it's the same support issue already mentioned. You should ask them.

 

[Noah Peters]

When you think about how potters go about making a bowl on a wheel, they start with a lump on the center of the wheel, molding it with their hands. Regarding the shape, think about wet, flexible clay getting drawn out away from the base, thinner and thinner. Pretty soon there's not enough strength in the lower section to support the upper, and splot! One solution would be to draw the walls up more vertically. Another would be to have more thickness in the lower areas, which would produce a heavier overall, but especially bottom heavy, finished bowl.

If the ceramic bowls you're seeing have 50% bases, probably your local potters feel the need for that much of a base for some reason. Maybe it's the same support issue already mentioned. You should ask them.

I will look into that. thanks for the suggestion

 

[hughie]

I find that I tend design/turn along the lines of the golden mean although I dont measure or use gauge to check. But at the end of the day beauty is in the eye of the beholder. Sometimes I turn and carve a piece and think nah. But it is well received by all who see it, causing some bewilderment at times. Having spent a lot of time in South East Asia over the last 30+ years I find the ceramics there seem to have their own style not exactly the rule of thirds, this influence creeps into my thoughts on design

 

[Randy Anderson]

I will second the advice to get Richard Raffan's book. I have it here in my shop. Good diagrams, examples of good and bad, etc. Great resource.

 

[Noah Peters]

I will second the advice to get Richard Raffan's book. I have it here in my shop. Good diagrams, examples of good and bad, etc. Great resource.

This is good advice, I do have the book and it is very good and truly is a wealth of information. It is his thoughts on the matter and everyone has their own thoughts on this topic. What I was kinda hoping was to see what other peoples thoughts on this topic were and what they think about this type of design and on designing pieces in general.

 

[robo hippy]

In my years of making and selling wood bowls, one thing always cracked me up. Some one would come in and buy a deeper bowl 'because you can toss a salad better in it'. Then another person would come in and buy a shallower bowl 'because you can toss a salad better in it'. Me, I don't toss my salads because all the good stuff sinks to the bottom. Keep some ideas in the back of your head and just turn. Some times the wood will determine the shape, and some times you determine the shape...

robo hippy

 

[Randy Anderson]

Sorry, misunderstood the primary point of your question. I do mostly natural edge bowls but when turning I start at 1/3 the bowl diameter for the foot. For twice turned traditional I do the same but will often make them on the plus size knowing I can adjust when I finish turning and will want the wood available to give me some flexibility. I don't go nuts with measuring. I estimate with my fingers, it's close to 1/3, done. With natural edge there is always some adjustment and fixing needed when cleaning up the foot due to warping, potential cracks that have appeared, fixing the warp to match the original curve, etc. so end result is often a bit under 1/3 when done.

On the flat interior point I strive for a curve that makes a consistent arc from rim to rim across the bottom, especially on utility traditional bowls. I don't like a flat bottom in a utility bowl. On natural edge I often have a bit of a "flatter" area in the very bottom due to the oval shape of the bowl but not one that can be felt or notice due to a transition area or by the eye. It's still a curve, just less slope right in the bottom.

Here's a pic of one I just finished. Foot is 4 1/4, bowl is 10" wide and 13 1/2" long. I seldom make round natural edge bowls and use the length as my 1/3 basis for the foot. All that said, when done I always step back, examine the curve, look at the bottom and sometimes it just strikes me that the bottom is just too big for the look so I adjust slowly until it "looks" right.

 

[Lennart Delin]

I think that the size of the foot must be seen in the relation to the shape of the bowl. Almost all of my bowls have a parabolic or catenary shape. I want the wall thickness to be constant including the bottom. A deep bowl would look clumsy with a big foot and a shallow bowl would look strange with a small foot. Usually my foot is typically 1/4 to 1/5 of the diameter. For shallow bowls where I may want a bigger foot, I make it in the form of a ring. For twice turned bowls, which is the norm for me I completely finishes the foot before turning the inside. The bowls are 24x12 resp 30x10 cm
I should also add that my bowls are normally decorative pieces.

 

[Marc Banka]

Pottery is very much like woodturning in that most folks make stodgy, bottom heavy bowls that seem to imbedded a third of the way into the table. In either medium it’s a bit easier. And frankly, most folks are just used to seeing these shapes and accept it.
There are utilitarian ceramic pieces, such as casseroles that won’t have the same uplift and small base for practical reasons; stability on the table and especially in the oven. But even these, at least the nice examples, have a curve that still misses the table even while having a wider base.

In terms of process, when throwing a bowl with nice lift, one has to leave extra clay at the base to prevent the walls from collapsing. The bowl is set aside for a few days, till the clay is ‘leather hard’. The piece is returned to the wheel, bottom up for trimming, where the extra clay is removed and the foot is formed. Sound familiar?

A few years ago, I needed to step away from turning (major back issues) so decided to learn pottery. I surprised the folks at the studio at how quickly I learned and was making bowls that are light and graceful. My advantages were that 1. I have ‘good hands’, and 2. I understand what a nice bowl is. Strive for uniform wall thickness, a foot that is 1/3, more or less, a curve from one edge across the bottom to the other edge without hitting the table. This gives the work ‘lift’, an upward feel.
I made nice bowls because I know what a lovely bowl should look and act like.

Regardless of the medium one chooses, avoid stodgy work.

 

[Lennart Delin]

Pottery is very much like woodturning in that most folks make stodgy, bottom heavy bowls that seem to imbedded a third of the way into the table. In either medium it’s a bit easier. And frankly, most folks are just used to seeing these shapes and accept it.
There are utilitarian ceramic pieces, such as casseroles that won’t have the same uplift and small base for practical reasons; stability on the table and especially in the oven. But even these, at least the nice examples, have a curve that still misses the table even while having a wider base.

I agree completely