MAGNESIA SOLDERING BLOCK JEWELRY MAKING SILVER ART REPAIR & WELDING BOARD (E 7) MAGNESIA BLOCK SOLDERING WORK JEWELRY MAKING - SOLDERING & WELDING APPLICATIONS Magnesia Soldering Block, made of a soft (Non Asbestos) fibrous and fire-proof material. Magnesia block is able to tolerate heat temperatures up to 2000oF / 1090oC. Block is comparatively soft which permits steadying object into the surface or inserting pins to hold parts for soldering. Block can be easily refurbished to a smooth surface by slight sanding.