The main factor mentioned in the community answers is the steel wool grade: finer wool tends to spark better. Use very fine grades such as 0, 00, 000, or 0000, and avoid coarser grades like 1 and above if your goal is lots of sparks.

A short burn time is also normal. The sources referenced in the answers suggest that many steel wool spins last only around 5 seconds, so 7–8 seconds is not unusually short. If you’ve seen examples that appear to last longer, that may be due to wool grade, technique, or simply how the long exposure records the light.

In short: choose a finer steel wool grade if you want denser sparks, but don’t expect dramatically long burn times—brief bursts are typical.

Because steel wool photography involves fire and flying embers, use extreme caution, follow local rules, and work only in safe locations away from people and flammable materials.