What you see in picture 1 is a French tapestry of the 15th century representing the royal couple Charles d’Orleans and Marie de Cleves. I saw this image when I was reading a book about the ancient French literature; I threw a glance at the image, remarked an object in the Queen’s right hand…then stopped reading and looked at the image attentively. The object (its bigger view shown picture 2) happened to be nothing else than a watering can - so fascinatingly unusual that I decided to make something similar. I wouldn’t venture to make a replica, my craft skill being too modest for that, but I kept the overall shape and proportions of the original artifact. The overall height of my watering can is 32 centimetres, the diameter is 16 centimetres.
It works as follows: when you immerse the can into water, it enters the can through the holes in the can’s bottom under the action of atmospheric pressure; the air that is in the can goes out through the small hole in the cover of the can’s neck. Then you close the hole with your finger and take the can out of water. The forces acting now at the water in the can are: the atmospheric pressure and the pressure of the air remaining in the can (negligibly small compared to the atmospheric pressure); thus, the water remains in the can until you open the hole connecting the inside of the can with the atmosphere.
The materials used are discussed in the 'Raw materials' section. As to the tools, the following would be needed:
small gas torch
saw to cut metal
fretsaw to cut wood
pair of pliers
drill with bits
Also needed: coarse and fine sandpaper, pieces of plywood, wooden bars, small screws, used writing paper, piece of cloth, metal cleaning product
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Step 1: Raw Materials
The can consists of three parts: the bowl, the top and the neck. I used an old copper planter (see pictures 1 and 2) to make the bowl, a piece that used to be the cap of a vent stack to fabricate the top, and some pieces of thin sheet copper available at my workshop to make the neck.
The planter demanded a lot of polishing and cleaning work, as you could realize while comparing the images of the planter and the ready object.
Step 2: Make the Lobes
It was necessary to flatten the planter’s skirting before applying the template and cutting the lobes. For that, I placed the skirting on a massive wooden block and kept striking the metal with a hammer while turning the planter; thus, the skirting was flattened on all its circumference (see picture 1).
The template used to draw the lobes is shown in picture 2, I designed that template basing on the flat of sphere (see picture 3). The dimension ‘a’ in picture is calculated as: 2*pi*R/N, where R is the radius of the sphere, N - the number of the lobes (10 in my case).
Then I marked the outlines of the lobes on the skirting, cut and filed them. The result is shown in picture 4.
Then it was necessary to ply the lobes, with their edges slightly overlapping to eliminate the gaps between the neighbouring lobes. Picture 5 shows the beginning of the process. To achieve good fit between the lobes I held the rims of both lobes with a pair of pliers and made several light hammer strikes to the outer lobe along the contact line until the fit was satisfactory (see picture 5). The lobes should form a circumference about 110 mm in diameter.
Step 3: Stamping Work
To make the bottom of the planter hemispherical it was necessary to do some stamping work on it. First, the copper should be annealed to become softer and more malleable; to achieve this, you heat the metal until it becomes dark-red (about 650 C) and cool it in a basin of cold water. I don’t have a big gas torch that’s why I simply put the planter on a burner (see picture 1); the result was satisfactory. Use a pair of pincers to handle the planter during this operation!
I used a stack of papers about 15mm thick fixed together and placed on a wooden block as the support for the stamping work. The work was done using a hardwood pestle and a hammer.
The technique is to make a series of strikes while turning the pot, to extrude the concave parts (see pictures 2 and 3). The result is shown in picture 4.
The top of the can is also made through stamping work. I softened the raw piece, then extruded its central part by using a pestle, a hammer, and the accessory shown in picture 5. The accessory is made of a piece of 20mm thick plywood, and has two openings in it: one is 50 mm id diameter, the other 70mm. The raw piece was put concentrically on the smaller opening, several strikes were made; the resulted piece was softened again to eliminate stress, then put on the bigger opening, and more hits were made until the desired shape is achieved (see picture 6).
Step 4: Drilling the Bottom
The holes in the bowl’s bottom were made by the template shown in picture 1. The template’s outer diameter is 100mm, there are 5 concentric circles spaced at 10mm intervals. I glued the template concentrically to the bottom of the can, then marked the centres of the holes using a centre punch with fine tip (see picture 2).
There are 96 holes 1.6 mm in diameter (see picture 3).
Step 5: Neck
I would hasten to say that the best solution for the neck is to use a piece of copper tubing about 25…30 mm in diameter. Such piece not being available at my workshop, I made the neck of thin sheet copper; it’s not a great technique, but, at least, I practiced my soldering skill.
I bent a piece of softened sheet copper around a wooden stick 22mm in diameter; annealed copper is soft enough to bend with bare fingers; then I made several light hammer strikes on the rims of the bent piece, to make it rounder. The result is shown in picture 1. However, there remained a gap because of some elasticity of copper, so I made an overlay to cover the gap (see picture 2).
The overlay was fixed to the main piece using soft steel wire (see picture 3). The resulting tube is 24 mm in diameter.
The cover of the neck is 27mm in diameter and made of sheet copper, there’s a central hole 3mm in diameter in the cover. I made an accessory to ensure good soldering of the cover to the tube, see pictures 4 and 5. A wooden stick is placed inside the tube, the cover is fixed, concentrically with the tube, to the stick on one side; a piece of plywood is fixed on the other side of the stick. The assembly is then fixed vertically to a wooden bar. The soldering is made to produce a circular joint.
I soldered using a small gas torch and a 40W electric soldering gun; the solder was wire 2mm in diameter with flux inside, made of 99% of tin and 1% of copper. The technique is as follows:
put some resinous flux on the place of the future joint heat the joint with the gas torch apply some tin with the tip of the soldering gun keep heating with torch and uniformly distribute the tin along the joint
The picture 6 show the positioning of the torch and the soldering gun. I also used this technique to solder the lobes of the bowl and the top, as well as to make the general assembly.
Step 6: Soldering the Lobes of the Bowl
The bowl is fixed with two screws to a wooden bar, the latter being fixed to the workbench as shown in picture 1. (The screws pass through two of the holes drilled in the bowl’s bottom).
The bowl should be fixed in such a way that the gap to be soldered be directed upwards; thus, the molten solder easily flows into the gap.
I fixed the rims of the lobes with a bolt, 2 washers, and a nut, to assure that the gap doesn’t ‘open’ during the soldering, see picture 2.
The surfaces under and near the joint should be cleaned as shown in picture 3.
Wear goggles when soldering! Wear gloves when handling (if necessary) the piece immediately after finishing to solder! Copper having high thermal conductivity, the whole piece would be heated uncomfortably for bare fingers when you solder just one joint.
Step 7: Top
After the central part of the top was sufficiently extruded, I marked the outlines of 10 lobes using a template (see picture 1). I used a similar template to mark the outlines of the central hole, its diameter being 24 mm. The reason why I made the central hole after the extrusion was that I wanted to avoid cracks in the rims of the hole during the extrusion. The lobes should be plied so they slightly overlapped, the outer diameter of the top should be around 110 mm.
The neighbouring lobes should fit closely enough each to other; to achieve this, I put the top on a wooden block, and made several light hammer strikes on the inner surface of the ‘inner’ lobe (see picture 2).
Clean the rims of the central hole in the top and the rim of the neck which would be soldered into the top. Insert the neck into the central hole of the top, the fit should be tight enough to hold the neck in place. Check the vertical position of the neck. Solder the neck and the top in a point as shown in picture 3. (I tinned the rims before the soldering, but it’s not necessary). Check again the positioning of the neck and, if it’s vertical, solder the entire joint.
Fix the assembly to the workbench as shown in picture 4; solder the joints. The gap should be directed upward, so the molten solder easily flows into the gap. The result is shown in picture 5. It’s necessary to file the rim of the top to obtain flat surface (see picture 6). the rim should be chamfered to allow more solder into the joint (see picture 7) during the final assembly of the watering can.
That’s why the groove is needed: if you solder a joint without the groove and then polish the joint (eliminating some solder, obviously), the quantity of solder is reduced and the joint becomes feeble. On the contrary, the groove allows you to both keep enough solder in the joint and polish the joint making it beautiful. The same method is used in welding.
Step 8: General Assembly
It’s necessary to file the rim of the lobes to obtain flat surface as shown in picture 1. The top is fixed to the base using the accessory shown in pictures 2 and 3. A piece of soft steel wire passes through the hole in the neck’s cover and the central hole in the bowl’s bottom; the upper end of the wire is attached to a pin, the down end is fixed in a threaded stub. When you tighten the nut on the bottom threaded stub, the wire tightens and holds both parts together.
The wooden piece to which the base is fixed (see picture 4), allows to place the assembly on the workbench in such a way that the joint to be soldered is situated horizontally; thus, the molten solder easily flows into the groove. The entire accessory is shown in picture 5; it allows to turn the assembly after a joint has been soldered, so the next joint is available for soldering. Wear gloves when handling the assembly after you soldered a joint! The thermal conductivity of copper is very high, so the whole object heats uncomfortably for bare hands when you solder just a joint. After the soldering was finished, I polished the joints using coarse and fine sandpaper; I removed the flux that remained on the surfaces using hot water and a wire brush). Then, I cleaned the entire surface of the artifact using a metal cleaning product.
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