713 secrets of industrial technologies (directory) - Version 1 1. Metals. 1. Steel training. 2. A way gland. 3. Iron drilling. 4. for forge forges. 5. pig-iron lattices. 6. Cold soldering. 7. A simple way . 8. The message to tin solder of copper colour. 9. Iron polishing. 10. Definitive furnish of metalwork products. 11. Transfer of drawings for metal surfaces. 12. Chemical ways of etching of metals. 13. A galvanic way of etching of meta