I have blooged about how I make cups here
http://www.hotdiptin.com/blog/how
What makes a tin cup authentic? By Dr. George Pimentel
All athentic civil war tin cups have some general similarities. In my collection I have three authentic tin tin cups, one tin can and one tin pitcher. I have compared my original tin cups with the tin ware collections in the Tennessee State Museum, Gettysburg National Battlefield Park, Antietam National Battlefield Park, the Civil War Medical Museum and countless antique shops and books. In general all period tin cups have the following key Characteristics.
The tin cup or more properly called coffee or tin "dipper" has a flat bottom. The bottom has a 1/8 to 1/4 inch uniformed lip and is soldered directly to the bottom of the cup (no crimped bottom - like a modern Campbell's soup can). the solder bead is readily visible on period tinware. Handles examined have either been "C" shape or "tear drop" shape.
The rims of the cups are finished with a wire rolled top, or in one case a folde top that was placed over the rough rim and seperately soldered, but this is only one example so far found of this type of rim construction. In general, modern reproductions suffer from being to perfect. In all of the cups I have examined, solder beads are not uniform and slight hammer strokes are noticeable (the difference between a hand crafted cup and industrially produced cup).
As mentioned above, handles come in two styles: the "C" shape and "tear drop" shape. All of the civilian cups I have examined have their handles soldered directly to the body of the cup over the seam with no wire or tinners rivets. The solder job here is noticeably sloppy as compared to the other solder seams.
This seams to have been done because the solder for the handles would have to drop on the handle of the cup to prevent the heating of the entire cup, which can cause (and usually does) the body seam to seperate. Civilian cups use thinner material than issue cups and tin cans. All of the cups examined measured between .016 and .012. In modern terminology we would say that this would be equivalent to 26-28 gauge tin plate. The best way to test the gauge of the metal is that you should be able to squeeze the cup in your hand slightly. It was also common practice because of the lighter material to bead these cups, which would add to their strength as well as being aesthetically pleasing.
On issue cups we find a few different characteristics. Besides the difference of the folded seam, issue cups are generally larger in size. The one I have in my collection is 3 1/8 inches high by 4 inches in diameter. Larger sizes were also available and averaged 4 1/2 inches high by 4 1/2 inches in diameter to 4 inches high by 4 inches in diameter.
The larger cups seem to have been produced earlier in the war but I have no concrete evidence other than the fact that the larger cups can still be found in museums and relic stores, but are noticeably less common (as seen in their purchase price). Another difference is the gauge of the metal. Issue cups measure on average .025 which would be the modern equivalent of 24 gauge tin plate. This makes the issue cup noticeably heavier and more durable.
Handles are also attached differently to the body. I have seen two different styles: top attached by wire and the bottom riveted and or by the use of three tinner's rivets, which would then also be soldered. Issue cups have a cleaner solder job used on the handles due to the fact that seperating the body seam is not usually a concern because of the folded seam. No beading has bean seen on any issue cup. These cups are overall stronger and would be more difficult to bend in the hand. They definitely show some forethought in trying to produce a cup that would withstand the rigors of campaign.
