Will these zip ties hold heat wrap in place permanently?

Stainless steel ties grip and stay locked once cinched — they won't slip or loosen from vibration. That said, heat wrap itself degrades over time depending on exhaust temperature and moisture exposure, so plan on re-wrapping every few years.

Can I reuse these if I need to unwrap and rewrap later?

Once a stainless zip tie is locked down, it's single-use — you'll need to cut it off. Keep extras on hand if you plan to service or replace heat wrap down the road.

Do I need anything else to secure heat wrap?

You'll need the heat wrap itself and these ties. Some builders also use high-temp adhesive tape at seams for extra hold, but ties alone will secure the wrap mechanically.