When finished, do not rush to sweep away the iron filings: putting them on paper with the help of the charge from the back of the magnet and adding rosin, it is possible to make flux for soldering pencil. It is particularly effective when the tinning of aluminum. Pour the molten rosin with the addition of sawdust into a tube, twisted impregnated with paraffin paper. After cooling this “joint” is easily unwound, freeing the finished rosin core.
V. FEDOROV, Chop, Transcarpathian region.