Practical Mechanics for Boys Part 18

Solution No. 3: Water, 32 ounces; sodium carbonate, from 4 to 6 ounces.

Fixing bath. Add two ounces of S. P. C. clarifier (acid bisulphate of sodium) solution to one quart of hypo solution 1 in 5.

Clearing solution. Saturated solution of alum, 20 ounces; and hydrochloric acid, 1 ounce. Varnish. Brush over the negative a solution of equal parts of benzol and j.a.panese gold size.

PLASTERS.--Court Plaster. Use good quality silk, and on this spread a solution of isingla.s.s warmed. Dry and repeat several times, then apply several coats of balsam of Peru. Or,

On muslin or silk properly stretched, apply a thin coating of smooth strained flour paste, and when dry several coats of colorless gelatine are added. The gelatine is applied warm, and cooled before the fabric is taken off.

PLATING.--Bronze coating. For antiques, use vinegar, 1,000 parts; by weight, powdered bloodstone, 125 parts; plumbago, 25 parts. Apply with brush.

For bra.s.s where a copper surface is desired, make a rouge with a little chloride of platinum and water, and apply with a brush.

For gas fixtures. Use a bronze paint and mix with it five times its volume of spirit of turpentine, and to this mixture add dried slaked lime, about 40 grains to the pint. Agitate well and decant the clear liquid.

COLORING METALS.--Brilliant black for iron. Selenious acid, 6 parts; cupric sulphate, 10 parts; water 1,000 parts; nitric acid, 5 parts.

Blue-black. Selenious acid, 10 parts; nitric acid, 5 parts; cupric sulphate; water, 1,000 parts. The colors will be varied dependent on the time the objects are immersed in the solution.

Bra.s.s may be colored brown by using an acid solution of nitrate of silver and bis.m.u.th; or a light bronze by an acid solution of nitrate of silver and copper; or black by a solution of nitrate of copper.

To copper plate aluminum, take 30 parts of sulphate of copper; 30 parts of cream of tartar; 25 parts of soda; and 1,000 parts of water. The article to be coated is merely dipped into the solution.

POLISHERS.--Floor Polish. Permanganate of potash in boiling water, applied to the floor hot, will produce a stain, the color being dependent on the number of coats. The floor may them be polished with beeswax and turpentine.

For Furniture. Make a paste of equal parts of plaster of paris, whiting, pumice stone and litharge, mixed with j.a.pan dryer, boiled linseed oil and turpentine. This may be colored to suit. This will fill the cracks of the wood. Afterwards rub over the entire surface of the wood with a mixture of 1 part j.a.pan, 2 of linseed oil, and three parts of turpentine, also colored, and after this has been allowed to slightly harden, rub it off, and within a day or two it will have hardened sufficiently so that the surface can be polished.

Stove Polish. Ceresine, 12 parts; j.a.pan wax, 10 parts; turpentine oil, 100 parts; lampblack, 12 parts; graphite, 10 parts. Melt the ceresine and wax together, and cool off partly, and then add and stir in the graphite and lampblack which were previously mixed up with the turpentine.

PUTTY.--Black Putty. Whiting and antimony sulphide, and soluble gla.s.s.

This can be polished finely after hardening.

Common Putty. Whiting and linseed oil mixed up to form a dough.

RUST PREVENTIVE.--For Machinery. Dissolve an ounce of camphor in one pound of melted lard. Mix with this enough fine black lead to give it an iron color. After it has been on for a day, rub off with a cloth.

For tools, yellow vaseline is the best substance.

For zinc, clean the plate by immersing in water that has a small amount of sulphuric acid in it. Then wash clean and coat with asphalt varnish.

SOLDERS.--For aluminum. Use 5 parts of tin and 1 part of aluminum as the alloy, and solder with the iron or a blow pipe.

Yellow hard solder. Bra.s.s, 3-1/2 parts; and zinc, 1 part.

For easily fusing, make an alloy of equal parts of bra.s.s and zinc.

For a white hard solder use bra.s.s, 12 parts; zinc, 1 part; and tin, 2 parts.

SOLDERING FLUXES.--For soft soldering, use a solution of chloride of zinc and sal ammoniac. Powdered rosin is also used.

For hard soldering, borax is used most frequently.

A mixture of equal parts of cryolite and barium chloride is very good in soldering bronze or aluminum alloys.

Other hard solders are alloyed as follows: bra.s.s, 4 parts; and zinc, 5 parts. Also bra.s.s, 7 parts; and zinc, 2 parts.

Steel Tempering-.-Heat the steel red hot and then plunge it into sealing wax.

For tempering small steel springs, they may be plunged into a fish oil which has a small amount of rosin and tallow.

VARNISHES.--Black Varnish. Sh.e.l.lac, 5 parts; borax, 2 parts; glycerine, 2 parts; aniline black, 6 parts; water, 45 parts. Dissolve the sh.e.l.lac in hot water and add the other ingredients at a temperature of 200 degrees.

A good can varnish is made by dissolving 15 parts of sh.e.l.lac, and adding thereto 2 parts of Venice turpentine, 8 parts of sandarac, and 75 parts of spirits.

A varnish for tin and other small metal boxes is made of 75 parts alcohol, which dissolves 15 parts of sh.e.l.lac, and 3 parts of turpentine.

SEALING WAX.--For modeling purposes. White wax, 20 parts; turpentine, 5 parts; sesame oil, 2 parts; vermilion, 2 parts.

Ordinary Sealing. 4 pounds of sh.e.l.lac, 1 pound Venice turpentine, add 3 pounds of vermilion. Unite by heat.

CHAPTER XVI

HANDY TABLES

TABLE OF WEIGHTS FOR ROUND AND SQUARE STEEL.

The Estimate is on the basis of Lineal Feet. 1 cu. ft. of Steel--490 lbs.

==========+===================+==========+=================== | | | | Weight in Pounds | | Weight in Pounds Sizes in | | Sizes in | Inches +---------+---------+ Inches +---------+--------- | Round | Square | | Round | Square ----------+---------+---------+----------+---------+--------- 1/16 | .110 | .013 | 1-1/16 | 3.014 | 3.400 1/8 | .042 | .053 | 1-1/8 | 3.379 | 3.838 3/16 | .094 | .119 | 1-3/16 | 3.766 | 4.303 1/4 | .167 | .212 | 1-1/4 | 4.173 | 4.795 5/16 | .261 | .333 | 1-5/16 | 4.600 | 5.312 3/8 | .375 | .478 | 1-3/8 | 5.049 | 5.857 7/16 | .511 | .651 | 1-7/16 | 5.518 | 6.428 1/2 | .667 | .850 | 1-1/2 | 6.008 | 7.650 9/16 | .845 | 1.026 | 1-9/16 | 6.520 | 7.650 5/8 | 1.043 | 1.328 | 1-5/8 | 7.051 | 8.301 11/16 | 1.262 | 1.608 | 1-11/16 | 7.604 | 8.978 3/4 | 1.502 | 1.913 | 1-3/4 | 8.178 | 10.41 13/16 | 1.773 | 2.245 | 1-13/16 | 8.773 | 11.17 7/8 | 2.044 | 2.603 | 1-7/8 | 9.388 | 11.95 15/16 | 2.347 | 2.989 | 1-15/16 | 10.02 | 12.76 1 | 2.670 | 3.400 | 2 | 10.68 | 13.60 ----------+---------+---------+----------+---------+---------

WEIGHT OF FLAT STEEL BARS.

=========+============================================================= Thickness| in | Width Inches | ---------+------+------+------+------+------+------+-----+------+------ 1/16 | .212| .265| .32 | .372| .425| .477| .53| .588| .63 1/8 | .425| .53 | .64 | .745| .85 | .955| 1.06| 1.17 | 1.27 3/16 | .638| .797| .957| 1.11 | 1.28 | 1.44 | 1.59| 1.75 | 1.91 1/4 | .85 | 1.06 | 1.28 | 1.49 | 1.70 | 1.91 | 2.12| 2.34 | 2.55 5/16 | 1.06 | 1.33 | 1.59 | 1.86 | 2.12 | 2.39 | 2.65| 2.92 | 3.19 3/8 | 1.28 | 1.59 | 1.92 | 2.23 | 2.55 | 2.87 | 3.19| 3.51 | 3.83 7/16 | 1.49 | 1.85 | 2.23 | 2.60 | 2.98 | 3.35 | 3.72| 4.09 | 4.46 1/2 | 1.70 | 2.12 | 2.55 | 2.98 | 3.40 | 3.83 | 4.25| 4.67 | 5.10 9/16 | 1.92 | 2.39 | 2.87 | 3.35 | 3.83 | 4.30 | 4.78| 5.26 | 5.74 5/8 | 2.12 | 2.65 | 3.19 | 3.72 | 4.25 | 4.78 | 5.31| 5.84 | 6.38 11/16 | 2.34 | 2.92 | 3.51 | 4.09 | 4.67 | 5.26 | 5.84| 6.43 | 7.02 3/4 | 2.55 | 3.19 | 3.83 | 4.47 | 5.10 | 5.75 | 6.38| 7.02 | 7.65 13/16 | 2.76 | 3.45 | 4.14 | 4.48 | 5.53 | 6.21 | 6.90| 7.60 | 8.29 7/8 | 2.98 | 3.72 | 4.47 | 5.20 | 5.95 | 6.69 | 7.44| 8.18 | 8.93 15/16 | 3.19 | 3.99 | 4.78 | 5.58 | 6.38 | 7.18 | 7.97| 8.77 | 9.57 1 | 3.40 | 4.25 | 5.10 | 5.95 | 6.80 | 7.65 | 8.50| 9.35 |10.20 ---------+------+------+------+------+------+------+-----+------+------

AVOIRDUPOIS WEIGHT.

For Merchandise of all kinds.

16 Drams (dr.) make 1 Ounce (oz.) 16 Ounces make 1 Pound (pd.) 25 Pounds make 1 Quarter (qr.) 4 Quarters, or 100 lbs., make 1 Hundredweight (cwt.) 20 Hundredweights make 1 Ton (T.) 2,240 Pounds make 1 Long ton (L. T.)

TROY WEIGHT.

For Gold, Silver, and Precious Metals.