Next time you need ballast (nose weight) try lead shot, but first use a plier to sqeeze them a little bit.
You’ll get two more benefits: they will no longer roll all over your workbench and some extra grip for gluing.
Sadly, with the run on ammo and related supplies around here I can no longer find a 25-lb. bag of shot… so I use fishing sinkers instead.
I have been using #7 birdshot for years… I still have about half of the amount left that I started out with some 25 years ago.
I have used lead ammunition shot, but as stated it is getting hard to find. I also use steel shot. It is not ammunitions grade stuff. It was designed for filling kettlebells and macebells (used in strength training competitions). I have used brass and steel BBs. I also use iron oxide sand blasting medium. It’s not as heavy but it’s cheaper and you can get more in a nose cone than shot, sinkers or BBs. The iron oxide and steel shot I mix with resin epoxy or CA. This makes a air/moister seal so it doesn’t rust. And it keeps in place forever.
There is a clay loaded with tungsten used to weight those pinewood derby cars. Haven’t found it at local hobby shops so I am looking for the stuff online.