Assignment 3 - Bowl Tutorial

Bowl-like shape, which is part of a sphere, is very common in our daily life. Therefore, bowl-making skill would be quite useful during specific model making process. This tutorial will present all information and technique which is needed through the whole bowl making process.

1. Preparation

1.1. Main Objects

From left to right:
Wood template, help first-shaping the flat aluminum into curve;
Sand bag, help shaping the clashed curves into a sphere;
Hammer, main tool to forming the bowl with a small sharp head and a big round head;
Fixing hammer, help fixing the sphere more smooth with dolly;
Dolly, help fixing the sphere more smooth with fixing hammer.

1.2. Supporting Item 1

From left to right:
Steel Scissor, to cut the aluminum sheet into circle;
Compass, to draw a circle on the aluminum sheet;
Marker, to draw auxiliary line on the aluminum sheet;
File, used to smooth the border of the cut aluminum sheet.

1.3. Supporting Item 2

From top to bottom:
Ear muffle, to prevent ears from the hammering noises;
Brasso, polish liquid;
Clean cloth, help polishing the sphere with brasso.

2. Sphere Hammering

2.1. Draw and Cut

Draw a circle on the flat aluminum sheet using compass and cut it to get a circle aluminum sheet. Marker can be used to make the drawn circle line clearer and do not forget to use file to smooth the cut edge.

2.2. Draw and Divide

Divide the circle into 8 equal segment using marker and also draw 2 circles which one has the 2/3 radius of the sheet and the other has the 1/3 radius of the sheet like the picture shown.

2.3. Hammering 1

First, hammering the 8 intersected points of the 2/3 circle and the 4 diameters. Place the intersection over the pit of the wood template and use the small sharp head of the hammer to hammer the intersection. Better to ham in one direction of either clockwise or anticlockwise.


After the first hammering, the aluminum sheet would bent like the picture shown on the left. Keep hammering through the 2/3 radius circle a bit using the small head and the sheet would bend with more wrinkles like the picture on the right. Do not hammer too many wrinkle, because the wrinkles on the edge of the bowl may clash and get overlap to each other. 

2.4. Sphere Making 1

Use the big round head of the hammer to hit the bend area between the 2/3 radius circle and the edge. Same as 2.3, hammering in one direction of either clockwise or anti clockwise.


After hammering using big head, the sheet would be looked like this in the picture. Do not worry of the ugly appearance. It is just the start.

2.5. Hammering 2

Same as hammering 1, but hammer the intersection of the 1/3 radius circle and the 4 diameters.

2.6. Sphere Making 2


Similar to the 2.4, using the big head of the hammer and hammering from the 1/3 circle to the edge. To faster and easier bend the sheet into a sphere, try to push down the opposite edge on the top while hammering. In this way, your bowl would bend deeper. Each time hammering, follow one radius and then slightly rotate the bowl and repeat the same process. Remember to hammer in one direction of either clockwise or anticlockwise.

2.7. Center

After a long period of 2.6 hammering and the achievement of bend bowl, hammer the center with the big head.

2.8. Surface Fix

After the above processes, you will get a bowl with a rugged surface. Use the fixing hammer and the dolly to fix the rug surface. As the bowl  is bigger and has a bigger radius than the dolly. Just place the bowl over the dolly and gently hammer the surface where the bowl and the dolly touched and then change the touched point and hammer it again.

2.9. Rough Bowl


After the fixing, a rough bowl appeared.

3. Bowl Perfection

3.1 English Wheel

There would be many dot on the bowl surface where you fixed the bowl and English wheel, which is the machine shown in the picture above, can help you fix the problem.

 
Like the picture shown, put the bowl between the 2 wheels on the English wheel and move the bowl in one direction through the diameter reversely. Rotate the bowl a little and repeat the wheel work.


You may get this kind of trace on the surface. Do not worry. This means that your wheel work is not done enough. Repeat the wheel work again and again until the traces are gone.

3.2. Hand Polish
The aluminum bowl is quite dirty and mess after all these processes. Brasso can help make the surface shine and smooth and clean.


First pour some Brasso on the surface. Use a piece of clean cloth and rub it to make the Brasso on the surface.


After rubbing, the surface would get quite dark like picture. Use another piece of clean cloth, because the last piece would get black after rubbing, and rub the surface emphatically.


Do the same polish work on the other surface and you would get a shiny bowl.

4. Reflection