"Everyman's Jet Engine" - Why Valveless Pulsejets? Built without any use of exotic materials For the pulsejet hobbyist, there is practically never any reason to go to exotic materials for engine construction. For beginner engines, and for low-cost prototyping of new experimental designs, nothing beats ordinary mild steel (unless there are weight concerns for some reason). The most expensive material 99 percent of hobbyists will ever need to use will be ordinary stainless steels (e.g. Type 304, Type 308, Type 316 alloys) which are readily available and not outlandishly priced, and can be bought in small quantities and in many different sheet thicknesses and bar sizes. There are two main advantages to stainless alloys: First, they are absolutely permanent, so you're building an engine that will literally "last a lifetime"; second, they are much stronger at red hot temperatures than any mild steel, so a much smaller sheet thickness can be used, thus providing much lighter weight for the finished engine. Note, however, that stainless requires better tooling and much higher levels of skill to work with, especially in the welding of your engine.