I
| Finely powdered glue | 4-5 | |
| Finest iron dust | 2 | |
| Peroxide of manganese | 1 | |
| Common salt | ½ | |
| Borax | ½ |
To be powdered extremely fine or levigated and made with water to a paste. Resists fire and hot water.
II
| Pulverised peroxide of manganese | 1 |
| White oxide of zinc | 1 |
To be finely pulverised and combined with silicate of soda.
An important part of all metal-mending is soldering. This is based on the principle that certain metallic compounds which fuse at a very low heat can, however, be so brought into union with others which have an affinity for them as by melting to unite the harder objects. Thus bismuth, which will melt in hot water, has an affinity for lead, which combines easily with tin and brass, &c.; as, in like manner, borax and resin with iron.
Newton’s solder (Lehner):—
| Bismuth | 8 |
| Tin | 3 |
| Lead | 5 |
This melts at 94.5° Celsius.
Rose’s solders:—