Some time ago I built a gasoline engine and boat, but when I put the rig on the river I found the engine would run for a short while and then stop. I found that the cause was some sand holes in the cylinder which admitted water into the bore of the cylinder. To stop the holes I used litharge and glycerine mixed into a stiff paste. The cement soon got as hard as iron and I had no further trouble from leakage. I have found that this cement is better than anything else I have ever tried. Dayton, Ky. Albert Elmiger.
A small hole or crack that is difficult to get at or that cannot well be soldered may be closed with an amalgam composed of zinc, 66 parts; tin, 44 parts; and sufficient mercury to make a stiff dough. The zinc and tin are to be melted together and afterwards granulated. The latter may be done by slowly pouring the melted mixture through a strong stream of water from a hose nozzle; or the filings may be used. The filings or granules are kneaded until an amalgam of the consistency of stiff dough is formed with the mercury. Excess of mercury should be squeezed out. The plastic mass is then forced into the opening and allowed to harden for an hour or two. It can then be filed and scraped like the metal itself. Only as much amalgam should be mixed as is required for immediate use. O. M. Becker.
A good mixture for plugging blowholes in cast iron is made of sulphur, cast-iron borings sifted very fine, and graphite. Melt the sulphur in an iron ladle and stir in as much of the sifted borings as the sulphur will allow, not making it too thick to pour readily. Add a small quantity of the graphite, say a tablespoonful to a quart of the mixture. Pour into the holes while hot, and after it is cool smooth off with a file. When holes are filled with this mixture on surfaces to be machined a finishing cut can be taken over it which will obliterate the holes. R. B. Casey.
Schenectady, N. Y.
I recommend the following formula for filling defects and blowholes in castings. I have been using this receipt for years and it is the result of many experiments: 1½ part litharge; 2½ parts dextrine; 4 parts iron borings or turnings carefully sifted. Mix the parts well, add water until the mass is of about the consistency of mortar. With a putty knife or other instrument fill the defective parts and press into every crevice. Let it "set" for 48 hours, when it can be chipped, planed, bored or turned like the casting itself. Color with lampblack to suit the shade of casting.
To facilitate the measuring of parts, use a box of three divisions, made to the following dimensions: The divisions for borings should be 4 inches long, 2 inches wide, 1 inch deep; for dextrine, 4 inches long, 1 ¼ inch wide, 1 inch deep; for litharge, 4 inches long, ¾ inch wide, 1 inch deep.
York, Pa. W. W. Birnstock.