DeLand pool. Improvised foundry, Daytona Beach. City fireman J.L. Clayton of Daytona Beach, Florida, turned curiosity into war production. Several years ago he became interested in molding metals, particularly brass and aluminum in his spare time and put up a one-man foundry in back of the fire station as a hobby. Now he's making cast parts for the DeLand industrial pool and turning out aluminum air raid sirens of his own invention. Clayton is pulling a newly-cast siren section out of the mold. With him is R.G. Campbell, Jr., foreman of his expanded hobby shop