Safety Fuse

Safety Fuze No. 9 Mk IV: This is a standard service fuse, frequently kown as "Bick-ford's", which is used for Detonators No. 25. The rate of burning is approximately 2 feet per minute. This fuse is of a larger diameter than No. 11, or No. 100, and when used with Briska Detonators No. 6, the outer layer must be peeled back before the fuse can be in-serted in the detonator.

Safety Fuse No. 11 Mk II: This fuse consists of a column of fine gunpowder enclosed in a jute yarn covering coated with bitumen and protected by a varnished black tape. The fuse has a diameter of about 0.21 inches. It burns at about 2 feet per second and will function under water.

Safety Fuse No. 100: This fuse is smaller in diameter than service safety fuse and can be used only with Briska Detonators No. 6. The burning rate is approximately 2 feet per minute. The fuse is water-proofed, not water-proofed, but will burn under water not exceeding 10 fathoms in depth, provided it has not been immersed for more than 15 mi-nutes.

TNT Instantaneous Detonating Fuse Mk III (F.I.D.): This fuse consists of a lead and tin alloy tube, about 0.23 inches in diameter, filled with specially prepared TNT. It detonates at a rate of about 5,000 meters per second.

Cordtex Instantaneous Detonating Fuse Mk IV: This fuse consists of a core of P.E.T.N. surrounded by cellophane tape and enclosed in layers of jute and cotton yarn, contained in a tubular covering of waterproof composition, which is aluminum in color. The external diameter is 0.9 inches. The rate of detonation is approximately 20,000 feet per second.

Some issues of Cordtex will be covered with rubberized tape instead of cellophane tape. Packages containing these issues will be marked "R". Packages containing Cordtex covered by plastic instead of bitumen will be marked "P".