I have looked into this a great deal and have made a few discoveries. Whilst not the most experienced soaper, I will share with you my findings on cpop soap and quick curing time.
Logically, if you know that saponification will be complete within a couple of hours, then the 4-6 week curing time that most experienced soapers will insist on is purely to let water evaporate and allow your bars to get harder, usually a better lather too. Following that logic, if you use less water, you need less curing time. I have made 2 successful batches using a water to lye ratio of 1.5:1 and 1.25:1. The first was as hard as the soaps I have left to cure for 5 weeks (2.8:1) after just 48 hours and the second was as hard within about 36 hours. I've been using a bar from the latter batch on the kitchen sink which is almost constantly wet for 3 weeks now and it is still as hard as ever and seems almost the same size as it first was.
Some observations though:
1. Overheating is a real risk. 2 hours is far too long for my soaps in the oven. If you leave them in this long with the oven on, yes they will be really hard because a lot of evaporation will have already occurred before you pull them out but be prepared for potential overheating issues like the top layer going bubbly or funny textured. You will have to either be ok with them looking unsightly or shaving that layer off.
2. Trace will happen a lot quicker so you may not get the smoothest top when pouring into your mould. Swirls may also be difficult. You can account for this by planning your bar to be relatively simple in comparison to really fancy-pants swirls etc. You will have to work more efficiently than normal.
3. 1.25:1 water to lye ratio is a brave one. All measurements have to be super accurate. You may find it hard to dissolve your lye. There is a risk your soap may be too dry or become cracked or brittle. (This did not happen to me.)
4. The 4-6 week curing time is definitely beneficial if you use a normal ratio. The finish on these soaps compared to the soaps in questions will be different... Hard to explain.
5. Fragrance oils and other stuff you might add will also make a difference and their behaviour must also be accounted for, as will the size, shape and material of your mould.
I haven't been soaping for very long but have spent a lot of time trawling through soap forums and I have realised that a) a lot of people seem hesitant in trying out new things. I read a post by a woman on another forum who said she'd been soaping for 2 or 3 years and had never tried cpop and was wondering about it. Her last post on that thread stated that she didn't feel like she'd be ready to cpop for another year or so yet. It made me sad. Life is too short to postpone trying new things for a year and humans are too capable a species to lack that much confident in their abilities b) I am a bit of a rule-breaker in soap. I have done a lot of 'naughty' things in my soap experiments and have learnt more in the last x period of time since I've been soaping than I would have if I stuck to the 'rules'.
Most important thing I could tell you: people will swear by their method and tips but they might not work for you. Go research, experiment and make up your own mind!
Let us know how you get on.
