Advanced Hollow Construction: Lesson 2: Cylinder

Lesson 2: Cylinder

C is circumference of your circle/ring, the length of the strip you are cutting.
D is the diameter of the circle.
Pi = π = 3.14
Example: If you want a 2” diameter cylinder, π(2)= 6.28”= the length of the strip.

Mark a line at each end of the strip with your dividers.
Place the strip in the vise with the protective plates in place. The line you scribed should line up with the top of the vise.
Push over to bend.
Repeat with the other side.
Bend in the center of the strip so that the edges meet.

Bring the edges down so that they meet level. To do this, hammer with a mallet on the shoulders of the ring to bring them in.
You want the ends to meet level so that there is the most contact between them to create the strongest soldering joint. If the edges meet at an angle the joint is more likely to crack under stress from forming.
Work the edges over and under to create tension.

Solder.
If you have solder spillage, file that off now. If the seam is pretty neat, don’t worry about it- check inside and outside!
Place on a mandrel, and hammer with a mallet to round out the ring.

Planish the ring. Begin at the seam, rotate the ring around while hammering and end at the seam.
Check that the sides of the cylinder are parallel and not flared by placing it on the steel square.
Mark any areas that are too low (where you see daylight) and hammer those areas.
File the top and bottom edges flat.
Use the steel square to make sure you are filing flat and not at an angle.
Solder your cylinder to a bottom plate.
Drill a small hole in the bottom plate for your air hole.
Cut off the excess bottom plate.
Solder cylinder to a top plate.
Cut off the excess.
Close your airhole.
File and sand your cylinder to 600 grit.

To close your airhole:

· After you are certain that the solder seams are complete on your piece, neutralize the pickle and draw out all water.

· It is very important to make sure that there is no water left in your piece before plugging the airhole!

· Heat the piece very gently (as if you were annealing) until all water has evaporated.

· Cut a small piece of wire that fits tightly into your airhole. The wire should stick up above the top surface by about 1-2mm.

· Flux and solder.

· It is very important that you solder the wire in place with one try! Double check that it is fully soldered before placing in the pickle.

· Clip off excess wire, and file flush to the surface.

Tips and tricks:

When deciding on what diameter you want for your cylinder, make sure that you have stakes to hammer and form with that are a bit smaller than your diameter. Otherwise you will not be able to fit onto a mandrel until it is already perfectly round. Likewise, make sure we have a mandrel that is very close to your final diameter otherwise rounding and planishing are trickier.
If you are using a tapered mandrel, hammer the bottom half of the ring, flip it over on the mandrel, and hammer. This way you are hammering on the same part of the mandrel.
When soldering your ring together, place the ring on top of a solder ball. When the ring drops down to the surface of the board, you know that solder has melted. This also reduces cleanup.
If you need a mandrel to form around, pipe from the hardware store is an excellent solution.

Homework:

Create a cylinder from 20ga. brass. The cylinder should be 1.5-2” tall with a diameter no smaller than ¾”. The cylinder should be sanded to 600 grit.

Due at the beginning of class September 12

Advanced Hollow Construction