2870. Clarified Linseed Oil for Varnishes

2870.    Clarified Linseed Oil for Varnishes. Heat in a copper boiler 50 gallons of finseed oil to 280° Fahr.; add 21/2 pounds of calcined white vitriol, and keep the oil at the above temperature for i hour; then remove it from the fire, and in 24 hours decant the clear oil, which should stand for a few weeks before it is used for varnish.

2871. Wilks' Refined Linseed Oil

2871.    Wilks' Refined Linseed Oil. In 236 gallons oil pour 6 pounds oil of vitriol, and stir them together for 3 hours; then add 6 pounds fullers' earth, well mixed with 14 pounds hot lime, and stir for 3 hours. Put the oil into a copper boiler, with an equal quantity of water, and boil for 3 hours; then extinguish the fire, and when the materials are cold draw off the water, and let the oil stand to settle for a few weeks before using.

2872. Boiled Oil for Varnishes

2872.    Boiled Oil for Varnishes. Mix 100 gallons linseed oil and 7 pounds calcined white vitriol (sulphate of zinc) in fine powder, in a clean copper boiler; heat it to 285° Fahr., and keep it at that temperature for at least an hour, constantly stirring it; then allow it to cool; in 24 hours decant the clear portion, and in 3 or 4 weeks rack it for use.

2873. Cautions Respecting the Making of Varnish

2873.    Cautions Respecting the Making of Varnish. As heat in many cases is necessary to dissolve the gums used in making varnish, the best way, when practicable, is to use a sand-bath, which is simply placing the vessel containing the varnish, in another filled with sand and placed on the fire. This will generally be sufficient to prevent the spirits catching fire; but to avoid such an accident (which not unfrequently happens), it will be best to take a vessel sufficiently large to prevent any danger of spilling its contents; indeed, the vessel should never be more than two-thirds filled. However, a piece of board sufficiently large to cover the top of the vessel should always be at hand in case the spirits should take fire; as also a wet wrapper, in case it should be spilled, as water itself thrown on would only increase the mischief. The person who attends the varnish-pot should have his hands covered with gloves, and, if they are made of leather, and rather damp, it will effectually prevent injury. These cautions should be well observed, or shocking personal injury may result from their neglect. In the city, it is hardly worth white to make varnish, unless in large quantities, as there are many stores where it may be had very good, and at a fair price; but in the country, where the freight is an object, and you cannot depend upon the genuineness of the article, it is necessary to be known by the practical mechanic how to make it; when it is available, it is best to purchase it. The varnish generally sold for varnishing furniture is white hard varnish.