You must be an expert armorer for this to work.
First, buy (or make) a cheap bind spell - it can be anything and last for as long as you like.
Second, hotkey your repair hammers.
Then summon your chosen item and quickly press the chosen hotkey to get your repair menu up.
Repair the bound item to 125 health.
You can repeat this for as long as you like (as long as you have enough hammers).