Basic Tinsmithing

Art. I. Tinsmithing for Those With More Than the Usual Number of Thumbs, by J. Gottfred.

In which the author describes some basic techniques for the making of tinware.

Tinsmithing is a surprisingly practical skill for reenactors. Compared to other historic skills such as blacksmithing and woodworking, it requires only a few simple tools and can be done in a fairly small work space. With the exception of tin plates & cups, tinware is noticeably lacking from most reenactor’s kit. This may be due to a lack of information regarding its historical use. It is difficult to get good archeological information regarding tin-plated items because tin-plated steel is so thin that it rusts to nothing in a very short time. The bits and pieces of tin work that have been recovered from fur posts are usually so rusted that it is impossible to determine what the object was originally.

Tin-plate objects were used in the fur trade. Cups and plates are mentioned in journals as part of the personal possession of clerks and officers, tin dispatch boxes were used to carry company correspondence, and tin trade kettles were occasionally sold as trade goods. Journals and inventories also mention tin tea kettles, tin basins, tin pans, and tin funnels.

With the exception of trade kettles, tin goods seem to have been restricted mostly to the personal effects of the traders themselves. The fact that tin-plate goods did not occupy a significant role in trade is not surprising. Tinware is not as tough as copper or brass, and it is not as well suited for rough usage. Scratched tin-plate rusts rapidly. Nevertheless, tinware was available, and such goods can occupy an important niche in any interpreters kit.

In this article I will demonstrate some basic tinwork techniques that anyone (even the author!) can do. With a little practice, you can turn out serviceable goods to meet a variety of needs.

Material

The material to use is called tin-plated steel, or tin-plate (.012" thick). This is basically the same stuff that was used 200 years ago. Finding tin-plate can be difficult.

You will find that most suppliers carry galvanized steel. This is dull gray stuff that looks nothing like shiny tin-plate.

Figure 1 - Examples of items made by the author from tin plate. From left to right : funnel, parallel glasses (artificial horizon) & case, dispatch box, telescope case, flask, small oil bottle, small tin medicinal, large oil bottle, flint & tinder box with candle holder.

Basic Tools

All you need to get started is the following :

A good pair of tin snips— I use aircraft aluminum snips which make cutting tin a breeze.

Rawhide hammer— Many tool suppliers will carry these, and so do all leather-working supply houses. Such a hammer is needed to avoid marring the tin surface.

Soldering iron— Don’t get one that is too small. I use a 100-watt plug-in type with a 3/8" inch wide tip.

Lead-free solder & soldering paste (flux)— You must use lead-free (plumber's) solder for any tin work that will be used as food items. I use only lead-free solder because you never know how something might be used in the future. This kind of solder is readily available at hardware stores.

12-gauge steel wire— Used to strengthen cup lips & handles, this is readily available at hardware stores.

In addition to these basic tools, you will find that a drawing compass, a marking gauge, a small brush for applying flux, a pair of needle-nose vice grips or some very small 'C' clamps and possibly some small files to be very useful.

Mandrels

You will need several mandrels to help shape the tin. These can usually be found in scrap yards or at metal suppliers. The best mandrels are solid steel, have flat surfaces and sharp edges, and are neither rusty nor greasy.

Figure 2 - Mandrels & rawhide hammer.

You will need to find a nice flat straight-edged piece, as well as cylinders in various diameters. For very small diameters you can use hardwood dowels. The larger diameters will be used to form bottoms. If you find a piece that is the exact size of the bottom that you wish to make, you will find that very little skill is required to create a perfect bottom.

Making a Gill Cup

In this article I will discuss the most common tinsmithing techniques while showing how to make a gill measure cup. (A gill is 1/2 cup). I suggest that you start with a cup a bit larger as you will find the material easier to work with.

First, select a mandrel to use for your cup. I suggest that you try to find one about 3" in diameter. For the gill cup, I used a 2" diameter mandrel (second from the left in figure 2).

Using a compass, draw a circle with a radius 1/8" larger than the size of your mandrel. Cut out the piece with your tin snips (Figure 3).

Figure 3 — Cutting out the bottom.

Center the bottom over the mandrel, and using the rawhide hammer, knock the 1/8" edge over to form a 90° lip. You can’t hammer the edge down all at once. You will have to bend it a bit at a time, working your way around and around the piece until you finally get it to 90° (figure 4).

This step is the most difficult to perform. If you don’t have a mandrel of the exact size of the bottom you are trying to make, you will find that this step requires a certain amount of skill.

Figure 4 — Making a lip around the bottom.

Once the bottom is formed, you can measure and cut out the rectangular piece that will form the sides of the cup. Decide how tall you want the finished cup to be, then add 3/16" to that value and mark the tin plate. I use a marking gauge for this kind of work (figure 5)— it really speeds up the process and reduces measurement error.

Next, you must determine how long to make the side piece. Take the diameter of the mandrel that you used (the diameter of the inside of the cup bottom), multiply it by 3.14, and add ¼". For example, with my 2" mandrel, the length I compute is 6½". Mark the piece, cut it out (figure 6), and flatten it by placing it on a flat surface or flat mandrel and tapping the edges with the rawhide hammer (figure 7).

Figure 5 — A marking gauge makes marking tin easy and accurate. Tin plate is very slippery, making it difficult to keep a normal straight edge in the correct position.

Figure 6 — Cutting out the corner piece.

Once the piece is flat, scribe a line along the top, 3/16" down from the edge, and along the side ¼" from the edge. Cut out the little square where the lines meet, and flatten the piece again (figures 6 & 7).

Figure 7— The tin plate can be flattened after cutting by placing it on a flat surface and hammering the edges with the rawhide hammer. The same technique can be used to straighten the steel wire.

Next, cut a piece of 12-gauge steel wire that's ¼" shorter than the length of the side piece. Straighten the wire by placing it on a flat surface or flat mandrel and hitting it with the rawhide hammer.

Now, using a straight mandrel, hammer the 3/16" top edge over to a 90° angle (figure 8).

Figure 8— Folding the 3/16" edge.

Flip the piece over, and hammer the edge over a ruler (I use a piece of heavy, flat brass) to form a U-shaped channel (figure 9).

Figure 9— The U-shaped channel.

Insert the wire in the channel, and hammer the tin down around the wire. The idea is not to pinch the wire, but to wrap the tin right around it (figure 10). This process can be aided with the edge of a tool like a screwdriver (I use my handy piece of brass again) to help tuck the edge in around the wire. Just work the material slowly, taking many passes, bending the metal a little bit each time, and you will find that it is not too difficult to get the wire wrapped up nice and tight. Note : don’t let the wire stick out into the ¼" gap along the one edge!

Also note: the wire is on the outside rim of the finished cup.

Figure 10— The wire has been wrapped by the edge.

You can now begin bending the side of the cup to form a cylinder. To get a nice smooth curve, you must gradually bend it over a mandrel (figure 11). Use even hand pressure and don’t bend it too much at once. Continue to bend it all the way around until the wire ends touch and the ¼" ‘flap’ overlaps the opposite edge. The ends are quite stiff, and you will need to tap them using a smaller mandrel to get the fit just right.

Figure 11— Bending the side of the cup around a mandrel.

Check the fit with the bottom (the sides fit inside the flange on the bottom), and make the cup's lip a true circle by placing the sides over the mandrel and tapping the wire-bound edge with the rawhide hammer (figure 12).

Clamp the piece together just at the edge (don’t clamp it anywhere else or the tin will show the marks). I use a pair of needle-nose vice grips to do this. Using a small brush, apply flux along either side of the seam. Then you can solder the joint.

Doing a good job of soldering is not very difficult if you keep two rules in mind : 1) Solder flows only where there is flux, so you must put flux wherever you wish the solder to end up. This rule also means that you must keep the flux away from places where you don’t want solder to end up. So keep your piece clean! 2) You can’t push liquid solder. Solder will melt and flow towards the source of heat. If you get a little blotch of solder off to the side of your seam, just keep the soldering iron between the blotch and the seam until the solder melts, then drag it back to the seam.

Figure 12 — Truing up the sides of the cup.

Figure 13 — Applying flux prior to soldering the sides.

Start with a small amount of solder on the end of your iron and apply it to the seam. Use a stick to push the seam together. You don’t need huge amounts of solder. Just keep traveling up and down the seam with the iron until you get an even finish. If you get too much solder on the piece, drag it to one of the edges where it will come off on the soldering iron or where you can tap it to the floor.

Keep the piece clamped until it has cooled, then wash off the excess flux with soap and water.

You can now true up the cup by hammering it gently on a round mandrel.

Figure 14 — Checking the fit of the bottom.

Once you are satisfied that the sides are as circular as you are likely to get them, place the bottom on the cup (flange on the outside) and check the fit (figure 14). Note that the flange will not meet the sides perfectly at this stage. Place the cup near the edge of a flat surface. Now go around the bottom of the cup, gently hammering the flange up against the sides. You should be able to close any gaps between the sides and the flange in this way.

Apply flux, then solder the bottom. In the illustration, you can see me using a small piece of wood to insulate my fingers from the hot tin (figure 15).

Figure 15 — Soldering the bottom.

To make a ½" wide handle, I cut a piece of tin 1" wide and simply fold the tin over the wire along each edge (figure 16). It is difficult to wrap the tin all the way around a wire on such a narrow piece. Strictly speaking, I did not need to use the wire on such a small handle, but on larger cups using wire is a good idea, as it results in a finished product that is quite strong.

Figure 16— Forming the handle.

The handle is attached over the side seam with a more generous application of solder (figure 17), and voilà, we have the finished cup! (figure 18)

This entire project took me just under two hours to complete.

Figure 17— The placement of the handle.

Using these simple techniques, you can make all manner of useful little items. The following pictures give some additional techniques. Figures 19 to 21 give close-up views of how to do lids, hinges, and 'filed' tops and bottoms.

Figure 18— The finished gill measuring cup.

Figure 19— Filing. The top of this small flask has been finished by simply soldering the sides to a piece of tin, and then cutting and filing down the edges until they are flush with the sides. This technique works well with small objects. Note that the mouth of the bottle has been folded outwards— no wire is necessary on such a small lip.

Figure 20— Hinges An example of how to form a small hinge. The wire forms the hinge 'pin', and a simple piece of unsoldered bent tin goes through slots on both sides of the hinge to hold the two parts together.

Figure 21— Lids An example of how to place a lip around a tin's top to prevent the lid from sliding all the way down. Note that the lip has a wire (so that it does not flatten), but the rim of the top does not require one.

Folded Seams

For the gill cup, I used a simple 'overlapped' seam. This seam is suitable for any small object. The more sophisticated seaming technique called the 'folded seam' is best for larger objects. One of the advantages of the folded seam is that it locks securely, avoiding the need for clamps. You also don't need to worry about side seams springing open when you solder the tops and bottoms on. (This attribute makes the folded seam almost essential when working with copper).

The disadvantage of the folded seam is that you require a special seaming tool in order to make it. Fortunately, such a tool is easy to make. I used a piece of mild steel 6" long, 1" wide and 3/4" thick. I then filed a groove 3/16" wide and 3/32" deep in one end. (See figure 22)

Figure 22— The end of the seaming tool. Note that edges have been rounded slightly to prevent sharp edge marks from being punched into the metal when the tool is used.

Layout for Folded Seams

It's a bit more complicated to lay out a side piece for a cup with a folded seam than for an overlapped seam. The side piece for the overlapped seam was a basic rectangle with one corner cut out. The folded seam is trickier (see figure 23). First of all, you don’t want the seam to intrude into the folded lip, so scribe a line 1/2" from the top edge. Next, scribe a line 1/8" from the left edge (which will become the outside edge). Also scribe 1/8" along the bottom edge, and scribe 1/4" in from the right edge.

Cut out the following little pieces:

From the upper left corner, cut out the 1/2" by 1/8" piece.

From the upper right corner, cut out the 1/2" by 1/4" piece.

From the bottom left corner cut out the 1/8" by 1/8" piece.

From the bottom right corner cut out the 1/8" by 1/4" piece.

Figure 23— The side piece is more complicated for a folding seam.. Note that instead of cutting out rectangles, one edge is angled slightly— this gives helps with getting a perfect fit later.

Finally, you must now scribe 1/4" down from the top edge. This is the fold line for the lip. You must also scribe 1/8" in from the right edge.

Before you make the seam, fold the lip of the cup as for the gill cup. (Note that in figure 23 the side of the tin that we are looking at will be the outside of the cup, so the lip would be folded towards us.)

Now you can fold the seam edges. The left edge will be the outside edge. Fold the edge under along the 1/8" mark. Be careful not the flatten the edge entirely— simply make it a 'U' shape.

Next, fold the right (inside) edge over (towards you) along the 1/8" mark.

You can now bend the side piece into a tube. The two edges will hook together as shown above.

Place the edge on a mandrel, and use the seaming tool to punch the seam as shown in figure 24. It helps tremendously if you can have someone pull the sides apart so that the seam hooks together completely. Figure 25 shows how the finished seam should appear.

Figure 24— Use the seaming tool to punch the seam as shown. You may need to use your hammer to flatten the seam along the top after you have completed the punching. The finished seam should be well locked, and not allow any side to side movement.

Figure 25— This example of a folded seam on a copper lid by the author shows how the finished seam should appear, and how it meshes with both a lid/bottom and a lip.

Your first tinwork projects should use the simple overlapped seam, before trying the folded seam. Once you gain some familiarity with working with tin, you should have no difficulty making good strong folded seams.

Although I have been tinkering around with tin for a few years, club member Randy Chappel (an Historic Artisan for Alberta Culture in real life) recently got me working with copper. In the next issue I'll cover some of the tricks of copper working that Randy was kind enough to pass on to me, and I will show how to make nice copper trade kettles like those below.

(See "Making a Copper Trade Kettle")

Figure 26— Two copper trade kettles by the author in the 'late Hudson's Bay' style.