Under Tank Heater?

I have a Zoomed under tank heater that I removed from a tank that I was no longer using. I am constructing a new Viv and want to use it again. Does anyone know how to get them to stick again. Any help would be welcome thanks.

They don't advise it, probably because they want you to buy a new one.

It will not heat as well as there will be less of it contacting the surface.

I have siliconed them on before with no issues.
Or use duct tape to keep it on.

Thanks Mike I will give it a try.

And although it adds another layer -- someone here suggesting mounting on a piece of glass first, then securing the glass (Under Tank Heater side down) to the bottom of the tank. That way you don't have that problem the next time.

I used the glass from a picture frame at the $1 store, and attached it to my leopard gecko tank. I have slate tile as substrate and it just heats it enough (even through the frame, tank bottom and the slate) to give me the correct tummy temps for my girls. And when I want to rearrange their tank - I can move their hot spot if I want.

I mount all my heaters on plex. It means I can move them from one tank to another, and those reptile ones largely get TOO hot when directly on the glass. The critters can often burrow down through substrate (depends on what you have/use) and can cause severe burns by sitting on the hot spot. Adding layers can be beneficial.