Some of the Fireworks have parts that can be used for models.
Fireworks that shoot up in the air typically have plastic nose cones and square wood posts that can be adapted for scale models. If one can find them after they are shot up in the air you can reuse them.
Some stationary spark shower fireworks have plastic parts and square wood posts.
The plastic cones and other parts can be used to create industrial funnels and concrete pads.
The wood posts can be used to frame buildings in HO and O Scale. They can be trimmed on band saws if you need more timbers.
Fireworks burn rather hot. I would expect the wood to be burnt and the plastics to have at least partially melted and resolidified in a non-conical shape. Have you actually used parts from used fireworks?
I agree with Eric,finding the various parts AFTER setting something off would be pure luck, and they’d be melted\burned and useless…if you buy some fireworks then scavenge the parts from them BEFORE setting them off…you’ve wasted your money.
Try the local craft stores…A.C.Moore, Michaels, they have an abundance of wood\plastic craft parts suitable for layout use, even the local Wally Marts have a fairly decent selection of odds and ends that you’re looking for.
But I think your best bet for wood will be the LHS, balsa or bass wood isn’t expensive at all and you can usually find a ends and pieces bag for around $7, there’s enough wood in there to keep you building for a while.
But the Old Dog must ask, are the parts worth losing an eye or hand? Fireworks contain explosives such as black powder. One spark and you are in for a nasty surprise.
Judging by the parts/pieces left over in the neighborhood street where the local teen launch their several day long display there are various parts, cones, sticks wrappers and empty beer cans left over in the middle of the street. Several plastic things that look like bases for something that was to be launched. Usually a couple of days recovering is what they need and they are then able to go out and clean up their mess. At least they clean up after awhile.
So I would agree there are probably several unmelted. unburned parts that could be used to make something out of. What if you were building a fireworks factory and needed burned boards, couldn’t get any more accurate than that for weathering!
You don’t need fireworks to get nose cones etc., as there is a large selection of available rocket parts for Model Rocketry. I know my LHS Maritime Hobbies and Crafts sells all kinds of rocket kits.
The fireworks remains in my neck of the woods (woods? WHAT woods?) aren’t worth having. 99.44% of them land in the street, and being run over by traffic (which is heavy at all hours) doesn’t improve them.
Slightly [#offtopic], but appropriate. I vaguely remember an E. L. Moore fireworks factory project in one of the model railroad mags (Wan Ka Pow Fireworks Company?) which he blew up with a firecracker (last photo in the article.)
Having worked with more serious explosives, I don’t do fireworks.