DCC Concepts OO DCT-LLD Liquid Lead Shot Weighting 500gm.

Lead remains the best choice for adding weight to locos though as it is double the weight of the castings used in models volume for volume.
The fine size of the shot makes it easy to use – so it is the perfect way to add loads of weight in a small or awkward space. 500gm (about 1.1 lb) is enough for many N or OO/HO locomotives. Add the pellets then secure with varnish or superglue.