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Spouts that drip or don't drip have long been something of a mystery to many potters. The problem is sometimes minor when a spout has one or two drops dribble down the outside of the teapot when pouring is stopped.
Once in a while some of us will make a teapot that dribbles a continuous stream of water down the outside of the teapot, while at the same time, pouring a stream of tea where it is supposed to go.
What is the difference and what is going on?
Some say that the spout needs to be wide enough at the pouring edge so as not to gurgle and also have a sharp lip to prevent dripping and be attached so that the open end is higher.
Others say that the rim's edge is very important for this operation and potters have all sorts of tricks to achieve a good looking lip that also pours well and this gives rise to a nice rising lip with a sharp edge that will cut off the liquid.
We know now, that having a sharp edge is not the complete answer.
A lot of artists have made more than a few spouts with sharp edges that still drip or dribble.
If the spout tip is horizontal or pointing downward when liquid begins to flow,
the spout will not drip.
The spout needs be only long enough to give a well directed stream of tea into the cup.
Usually, it sticks out no more than about one half of the diameter of the body of the teapot.
It can either be a tapered or a tube like form.
A spout that has a lot of taper with a very wide base narrowing down to a small opening, may create turbulence in the liquid and cause gurgling.
The inside of the spout needs to be at least as large as the diameter of a fountain pen and it can be bigger than that and still pour well.
It should be smooth inside.
The spout should end with a sharp lip which cuts off the flow of tea and prevents dripping.
The direction of the spout at this point should be parallel to the table and then when the teapot is tilted, the area just under the edge of the spout lip will be uphill to the tea.
A feature that helps to prevent dribbling is a little ditch or channel cut on the inside of the spout beginning at the very edge or lip and running back a bit into the spout. When the pour is cut off, the tea tends to run back down this little groove instead of down the outside of the spout.
Having heard the importance of a sharp edge.
I believe the direction of the spout is often ignored and is what gets most people into trouble.
The direction of the end of the spout, when the teapot is full, tilted slightly and just starting to pour, needs to be horizontal or pointing a bit downward.
This is shown in the drawing above.
As you look at this picture, think about what would happen if the spout shown were cut off at the lower arrow instead of being the length and curvature shown.
It is not hard to see that the stream of liquid would split into two parts, with some going where it was intended and the rest dribbling down the surface of the spout.
The same principles, sharp edge and horizontal direction, apply to open spouts such as those on pitchers or gravy boats, but in open spouts, it seems easier to achieve.
I think thrown spouts are the biggest dribblers because they are usually straight pulling or bending a slight curve into them after they are thrown would be a big help. They are often so short they have to be mounted high on the teapot in a near vertical position to get their opening above the top of the liquid in the pot.
One more point needs to be mentioned.
The wet ability of your particular glaze or clay surface by liquids can also be important in determining whether or not your teapots drip.
To find out about wet ability, carefully place a drop of water from a medicine dropper on a horizontal section of one of your glazed teapots.
Does it stand up tall like water on a freshly waxed surface or does it immediately spread out and run?
With everything else being equal, a glaze or clay surface that wets poorly, meaning the water beads up on it, will be less likely to drip.
With such a surface, you may not have to be as cautious about having sharp edges and horizontal lips as described above.
If your glaze surface is very wet able, you may have to have a sharp edge and a significant downward slope to the lip of your spout in order to achieve a drip free pour.
The correct way to make no drip free teapots is not widely understood, because I have seen several award winning teapots in recent issues of various craft magazines that I know do not meet the criteria described above.
I would bet some of them are serious drippers and apparently have been judged only on their appearance and not on their functionality.
Go ahead and make a teapot and see if any of these ideas help you to make a drip free or dribble less pot.
If these ideas don't help you, why not experiment and see if you can find a solution to this century old problem!!
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