Since the model is made out of styrene, it weighs next to nothing. I want to run the car empty from time to time, so I decided to conceal some lead shot in places underneath the model that are not visible when running on the layout. I glued the first layer of these down with superglue, but, using nearly the entire tube for that, I figured that I'd switch to something different. I decided to use Aleene's Tack glue for the remaining layers of lead shot I applied. I usually do one layer at a time to ensure that all shot is properly attached. What I did was I sprayed some rubbing alcohol on the loose lead shot, carefully placed some Aleene's glue over the area (which is rather thick), and then sprayed it with rubbing alcohol again. Before the glue dries, it will spread out and cover the entire area. Of course, this takes much longer to dry than superglue, but it costs less and holds just as well. I also put whatever lead shot I could fit into the center sill, without any of it being visible. It made quite a difference to the feel of the car.