Soldering Block Welding Solder Magnesium Jewelers Tool This is a new magnesia soldering block It is made of a soft, fire proof magnesia material Great for holding pins or small work pieces, soldering and fine welding Can withstand temperatures of up to 2000&#176; F (1093&#176; C) Measures approximately 6" x 3" x 1 1/2" (152 x 76 x 37 mm)