How to prepare the basic raw material for foam latex masks
We know of quite a few people wanting to custom produce their own realistic, scary or fancy dress masks from latex to fizzle at the point where they need to produce the raw material required for such masks and to employ it. The knowledge needed therefor is largely unknown, but not completely unavailable. An excellent place to look at professional knowhow are patent applications. By filing for a patent, inventors are granted the exclusive right to produce and market products based on the invention exhibited in the patent application. In return, they have to disclose the invention so that the formerly tacit knowledge is published to the interested public, which is, under normal circumstances, free to use the invention presented in the patent after the patent itself has lapsed (either through nonpayment of the fees or after a certain amount of time).
In the early 1990ies, a guy named Alfredo Garcia filed an patent for exactly this application of latex (publication number US4937023). As he failed to pay the fees in 1994, the patent lapsed and info made available should be free to use. The approach proposed by Mr. Garcia is, in short, as follows. First of all, i am assuming that you already produced a negative form of the mask you wish to cast. You are then adviced to fill the mold with natural latex rubber that was mixed with a suited accelerator as a vulcanisation agent and left to react and vulcanize. As such, the inventor advises to use a vulcanizing agent that is neither allergic nor carcinogen if used on human skin, preferably zinc dibenzoyl dithiocarbonate in a proportion ranging from 3% to 6%. The vulcanized mass should then be poured into the prepared mold. After a certain time, when the desired thickness of the latex film has formed as a film on the surface of the mold, the remaining fluids should be removed from the mold by means of centrifuging. Thereafter, the film that sticked to the mold has to be dried, preferably by applying heat from 50 to 90 °C. Afterwards, it should be possible to remove the mask from the mold for further processing, such as trimming of supernatant parts of the mask, cutting of holes for the eyes, nose and mouth and finally decorating the mask with adequate paints.
Please note that we can not take any responsibility that this is safe and actually works. A certain amount of testing might be necessary. For further information, please use the publication number stated above to look up the patent text in full as well as the pictures coming along with the patent.