Semtex

Semtex-H is a general-purpose plastic explosive (not to be confused with C4). It serves as a stand-in for TNT in some recipes that needed it or outright replaces it in some. It comes in a yellow-orange bar.

Production
The blend is made in a shapeless crafting recipe, it uses Solid Fuel, Niter, and a type of smokeless propellant. Cordite allows for 3 blends to be produced, while Ballistite only allows for 1.

This blend is then solidified and refined in an Ore Acidizer.

Uses
It replaces or acts as a superior form of TNT in various crafting recipes.

It is needed for propellant in some nuclear bombs.

A full block that is also a powerful explosive.

It can be used in the Custom Nuke. It contributes 8 to its TNT stage, which is twice as much as vanilla TNT.

Trivia

 * Can be eaten.
 * Plastic explosives are not actually edible, do not attempt this in real life.