Crack repair
Modern binders are safe and easy to use, they can also be used to glue broken metal objects, which, in the past, could only be thrown away. Adhesives are especially practical for joining materials, which have a low melting point, like tin or lead. Very high temperatures can also damage the patina on the surface of metals, as well as destroy wooden or bone inlays.
However, if the weld will be subjected to high loads, better to solder it. It is similar in the case of a small joint area. Two pieces of thin sheet metal should not be glued, without reinforcing them from the bottom with an additional strip of metal. Cyanoacetic adhesives are suitable for repairing minor defects, however, the joint will be stronger, if you use two-component epoxy glue.
Repair of a cracked fireplace casing
Scrub the edges of the joint and the back of the housing with warm soapy water. Wash with denatured alcohol or acetone to remove fat. Place the fireplace casing "upside down", to make it easier to fit the broken off piece. Stir the glue and apply to the edge of the joint. Put the broken off piece in the right place, slightly rocking it from side to side, for a better fit and squeeze out any excess glue. Tape both parts together. Wipe the stains off the glue with denatured alcohol. Leave to dry overnight. When the glue hardens, strengthen the back of the housing by gluing a glass fiber plate.
Gluing broken metal
After cleaning and gluing the joint, remove excess glue with denatured alcohol. Tape both parts together, that no air can enter the slot. Leave to dry overnight.