We sell a range of metal weights for calibrating scales at Gravitation. In addition to cast iron and brass weights, we also have a full set of F1 weights. Scale calibration weights vary in type depending on the application, but a good general rule of thumb is to use M1 class weights for scales with a coarse resolution of 0.1g, 1g, and over, F1 class weights for scales with a fine resolution of 0.0001g and E2 and E1 class weights for scales with a fine resolution of 0.0001g.
Where should you store your calibration weights?
If you want the weights to remain as accurate as possible, it is important that you store them correctly to keep dust from skewing their weight. Cast iron, brass, and any other type of weight should be stored properly. Usually, these products need to be stored in a wooden or plastic case that has individual compartments if they will be used frequently. Under no circumstances should a metal test weight be left on shelves or in a workspace exposed to harsh elements or dust.
How to clean calibration weights
Dusting regularly and soft-bristled brushes are the best tools for cleaning weights prior to every use; however, they should not be cleaned more thoroughly unless is more extensive, the weight may change, so measure the weight before cleaning and again afterwards to ensure that it hasn't changed.