Underwater Mask Manufacture I
Positive plaster cast of one subject's head and neck (J.L.), with spaces over eyes, nose, and mouth, and ears filled in, and (bakelite) tubing in place. Note smooth surface from which later casts in plaster or latex may easily be separated.

Underwater Mask Manufacture II
Dipping form for one subject (J.L.). A plaster bandage cast (negative) is made from the modified reproduction of the head and neck casting (#1) with a separating agent. Inside this negative mold, fiberglass cloth and resin is inserted to Construct the positive reproduction shown in this figure. The two white areas between nose and chin are the bumps for positioning the two tubes shown in Figure 3. The two halves of the fiberglass reproduction are assembled and fastened together with fiberglass tape and resin, and finally sanded. A base with a socket for a 75-watt heating lamp is inserted in this model.

Underwater Mask Manufacture III
The dipping form: mask insert in place on the face. (Heating lamp is lighted.) The mask insert is built of fiberglass on the dipping form with latex as the separating agent. The inspitatory and expiratory tubes (stainless steel) and the window (Lucite) are inserted and embedded in the fiberglass at the proper stages; three layers are built up. This form is separately dipped into latex, put on the headform, and the assembly dipped to generate the head mask (three to five layers of latex suffice).

Underwater Mask Manufacture IV
This is a finished mask formed by dipping cast shown in Figure 1, which does not contain a lucite window before the eyesÑnote breathing tube connected on one side. Note also the loose folds of latex at the neck which seal out liquid without undue constriction of subject's neck. Mask is donned simply by pulling down over head, much as a stocking would be. In place, it fits face and head closely, is smooth, and is completely comfortable, even for long time periods.