Key Clam Impressioning Shells

[LocksmithArmy]

final product

http://www.locksmitharmy.com/products.php

[Dopug]

once the impression is made, do you remove the key, close the clam, and pour metal into the top? I'd be worried about air bubbles getting caught and ruining the mold. do you thing this would be a problem?

if so could you someholw make a small vent hole in the side of the clam, a small metal cylinder could sit though this and the clay and connect to the teeth of the key, this could be removed when the liquid metal is poured in to allow air to escape, or it could even be used as an injection port?

[LocksmithArmy]

yes you stop air bubbles by tracing a small line from your impression to one of the divots you can see running down the side of the clam...
simplest solution.

[Riyame]

Seriously though, if you were going to do this get some 'chamber casting alloy' such as Cerrosafe from a firearms distributor like Buffalo Arms in Idaho, (but avoid Brownell's they want ~$46/lb).
Cerrosafe is the same stuff old timers used to use as kids to make toy soldiers.
It melts between 160°F and 190°F (optimum 165°F) and is safe to handle, (no Cd, no Pb).
It can be reused indefinately. Which is important, because this is a practice, practice, practice and still fail process.

EDIT: it wont allow spaces for the table, so just go to the website to view it properly.
Sorry bringing up the thread, but a quick thought: (Taken from http://en.wikipedia.org/wiki/Wood%27s_metal)
Cerrosafe is toxic.

Alloy Melting point Eutectic? Bismuth Lead Tin Indium Cadmium Thallium
Rose's metal 98 °C (208 °F) no 50% 25 % 25% – – –
Cerrosafe 74 °C (165 °F) no 49% 37.7% 11.3% – 8.5% –
Wood's metal 70 °C (158 °F) yes 50% 26.7% 13.3% – 10% –
Field's metal 62 °C (144 °F) yes 32.5% – 16.5% 51% – –
Cerrolow 136 58 °C (136 °F) yes 49% 18% 12% 21% – –
Cerrolow 117 47.2 °C (117 °F) yes 44.7% 22.6% 8.3% 19.1% 5.3% –
Bi-Pb-Sn-Cd-In-Tl 41.5 °C (107 °F) yes 40.3 % 22.2% 10.7% 17.7 % 8.1% 1.1 %

A better alternative may be Fields Metal. It is slighty more expensive, but is non toxic. I did a quick price check, and one company had it for ~$48 for a 12" x 1/8" piece (unknown weight) and another company had 4 oz ingots for $60. Another company made ingots to order but did not list prices.

[dll932]

Not for nothing but there are many places now that will do 3D printing of your CAD drawings on demand for likely much cheaper. Shapeways, Thingiverse and Cubify come to mind.