Magnetic Stirrers of Local Construction Long and Durham1 recently recommended adaptation of horseshoe-shaped magnets to the %-in. shaft of conventional stirring motors for use as magnetic stirrers. We have used this approach but have abandoned it in favor of constructing the magnetic stirrer shown in the figure. Our main objection to use of the reported adapter is that an unprotected rotating magnet is potentially hazardous. Actually, the stirrer housing shown in the figure provides a convenient and sturdy support for heating mantles. In addition, the aluminum plate of the housing provides the eddy-current brake suggested by Eikenberry.zFinally, the design and shape of mast mechanical laboratory stirrers do not lend themselves to inversion and adaptation as magnetic stirrers. The horsesboe-shaped magnet3 and shaded-pale induction motor4 were assembled into magnetic stirrers in our shops. The magnet was attached to the %-in. motor shaft with epoxy glue. We have varied the dimension of tho plates from 3 to 8 in. and the columns from 1%to 4% in., respectively to provide a range of sizes for different applications. Since the magnet3 is more powerful than those in our commercial magnetic stirrers, the chemists in our group usually favor the locally constructed ones. 'Long, Karen P., and Durham, Lois J., J. CHEM. EDUC., 5% 96 (1975). %rie F. Eikenherry, J. CHEM. EDUC., 52,385 (1975). SMagnet, horseshoe, Alcomax, size C, 1%"high X %" between poles, BA538. Laboratory Supplies Co., Inc., 29 Jefry, Hicksville, N.Y. 11801. Current price $7.15. This is equivalent to Eclipse brand, size C. dMotor, electric, Dayton, 3111247,11100HP, 1500 RPM, 115-V, 60 Hz, 0.5A listed by W. W. Grainger, h e . , 4273 Will Rogers PKWK, Oklahoma City, OK 73108, at $5..18. Oklahoma S t a t e University Stillwater, 74074
Heinz Hall E. J. Eisenbraun
Volume 54, Number 4, April 1971 1 228
