GB415181A - Improvements in hard soldering mixtures and hard soldering processes - Google Patents

Abstract

415,181. Solder compositions. LITTLEDALE, H. A. P., Crabtree, Streatley-on- Thames. March 23, 1933, No. 8712. [Class 83 (iv).] Metals and their alloys, particularly gold, silver, platinum, copper, nickel and silver or gold alloys, are soldered by the use of a soldering mixture containing no flux and no metal in the elemental state, but comprising one or more metallic oxides or salts together with sufficient carbon or carbonaceous material to reduce the oxide or salt to the metallic state and thereby produce the solder in situ. The carbon may be used in the form of or together with glue, gum, paste, starch, &c. and the mixture may be made into a paste or into a dry mass and used in such form or reduced to fluid condition by the addition of water. Glue may be diluted with a liquid preparation of carbon, such as Indian ink. When a carbonaceous cementing material such as glue is used, the mixture also serves to hold the work pieces together prior to and during soldering. The oxides or salts may consist of red or black oxide of copper, precipitated capric hydrate, copper chloride or acetate or verdigris or other copper salts, silver oxide, zinc hydrate, lead dioxide or carbonate, tin oxide or dioxide, or antimony trioxide. Mixtures of oxides may consist of 50 per cent of copper hydrate, with 30 per cent of zinc hydrate and 20 per cent of tin dioxide, or 66 per cent of silver oxide with 22 per cent of copper hydrate and 12 per cent of zinc hydrate, or 50 per cent each of silver oxide and either antimony trioxide or copper hydrate, or 25 per cent of silver oxide and 75 per cent of copper hydrate or 80 per cent of silver oxide and 20 per cent of antimony trioxide. Standard silver or 18 carat gold may be soldered with a mixture of glue and antimony trioxide alone or together with an equal amount up to five times the amount of silver oxide. 18 carat gold may also be soldered with a mixture of glue and equal parts of silver oxide and copper hydrate. When no-gaps in a joint in silver or gold are to be filled up, a mixture of glue with either copper hydrate or antimony trioxide may be used. For gold, gold oxide may also be added in proportions varying from 1 part of gold oxide and 1 part of copper hydrate to three parts of gold oxide and 1 part of copper hydrate. The composition in paste form may consist of 2 parts of oxides,-together with either 5 parts of the substances sold under the Registered Trade Mark " Seccotine," and 3 parts of water or 2À5 parts of anhydrous glue and 5À5 parts of water. A dry mixture may consist of 45 per cent of oxides and 55 per cent of dry glue. Soldering may be effected in a reducing atmosphere.