I want to try making liquid soap

I have looked up some recipes and it appears to take a few days to make. The first day it takes hours or stirring. I have also looked up making liquid soap from shavings of some of my soap bars that don't have a strong enough scent or cut wierd and that got kinda thick after a few days. Both recipes have water, the first is of course with the potassium hydroxide and the second water used in rebatching. Do I need to use a preservative?

Thanks