Yesterday I made another tin mold and today for the first time in a while I cast tin figures. Actually I melted almost a kilogram of pewter today turning all of it into figures of Littlefoot, Cera, Ducky, Petrie, and Spike making this my most productive tin casting section so far.
Anyway, here are the proceedings.
As I mentioned in another thread I recently got so called "shoe-charms" of the five land before time main characters. I don't know about their looks on shoes, but for the purpose of tin mold creating they are quite charming indeed. They are suited for making "flat figure molds". A flat figure in this context is a figure with only one detailed and elaborate side while the other side is plain and empty (like the first two figures I have ever made which are at the beginning of this thread). The making of such a mold is easier than that of any 3D figure (which consists of at least two mold parts while the flat mold is just a single part), but the casting of them can be quite tricky.
Here are the five shoe charms on a board which belongs to a disassembleable wooden box speciffically for the purpose of making molds:
Looking at it from the side you will see that all of the shoe charms are put on light-blue modeling clay. There are two reasons for this. One is that there is kind of a "button" behind the figures to attach them to shoes. That one is not to be molded. The main reason however is that the mold must be deeper than the actual figures are. If the mold was as shallow as the figures themselves there would be a high likelihood of the tin "spilling over" thereby making the figure unusable (apart from a certain risk). Moreover In case of these flat molds you need to be able to pour a relatively large amount of tin into the mold. The weight of the liquid metal presses the metal further down in the mold into the tight spots (such as Petrie's wings or any tail) which might otherwise remain empty which also renders the figure useless. In case of 3d molds you have a large usually conic hole into which the liquid metal is poured to fill up the form and provide the pressure on the metal down below. Flat figures lack such a cone which makes casting with them somewhat tricky at times:
The next two pictures show the wooden "walls" of the molding box assembled and fixed around the figures. Note the tape along the walls which is meant to prevent any of the liquid caoutchouc (still need to look up the spelling of that word) from which the mold is made from pouring out at the side:
The modeling clay at the side is another measure to prevent the possibility of caoutchouc leaking out there:
The red stuff is responsible for most of the mess that inevitably results from this work. It is the liquid caoutchouc. Never wear anything you still want to wear while anyone is looking when you do this work. There is NO chance in the world to ever get a stain of caoutchouc from any clothes. The blue liquid is responsible for most of the toxic and smelly vapors (gee how I wished I had an actual large hobby room with a BIG window for ventilation). It is the volcanizer which, mixed under the caoutchouc causes the later to become hard. In addition to that a so called "entl¸fter" (dunno the English term) is mixed into the caoutchouc to limit the risk of it creating air-bubbles:
A further measure to limit the risk of air bubbles on the figures in the mold is to attach some of the caoutchouc right onto the figures with a brush...
...before pouring the rest of the caoutchouc onto it filling up the whole mold box:
Next you need to wait for a day for the caoutchouc to harden (and I will finish this message here and continue in another because I'm afraid I might otherwise reach the limit for images in one message).
