Ah well I've just done my first batch of CP (cold process) soap. I've done a LOT of reading up in between the last post and now so in no particular order here's a few things I've done or found out.
- I went with a DIY wooden mold. I tend to OVERDO most things (somewhat a given as I'm a member here!) but wanted to make rectangular bars of soap. I also was happy to make a lil more effort so that the mold was easy to use, adjustable and durable for the long term. For me soap making will be purely for personal use - but I can envisage the vast majority of it being given away as gifts etc to family/friends.
Anyway read that plywood is much better for molds than straight pine as less prone to warping etc. Ended up stumbling across a great product in the trade/bulk materials section at Bunnings called Formply.
Formply is made of a high-density overlay (HDO) of phenolic resin impregnated paper bonded to plywood. It's specially made to have concrete applied to it in building work and was the same price as normal 15mm ply.
Being that it's made to have concrete put on it I'd imagine it's quite alkali resistant. The surface has a hard black coating that might even be able to be used without lining for soaps? If nothing else it should save people having to paint/varnish/oil their wood before use and provide an extra layer of protection against spills etc.
I've never heard of anyone else using it but from my preliminary investigations and it's zero marginal cost I would theorise there's an upside there for it in a soap mold.
I am still in that part of my life where I need to accumulate all my power tools so had to make so with using a handsaw! So cutting it was a handful but I got it done in the end. Cut across the shortest section of the Formply (I got a 1200 x 595 x 15 piece, was about $10). I wanted to make the bars 9cm in length, by 6cm in height, cutting them about an inch in thickness. So the pieces cut were roughly:
- One piece of 595 x 90 for use as the base
- Two pieces of 595 x 100 for use as the long sides
- Two 90 x 80 for use as the ends
- One 595 x 95 for use as the lid
I had been going to leave it all loose pieces and clamp together each time I used BUT that was just going to complicate things so I glued and screwed the sides onto the base, so I had a U shape but with no ends. Also an inch from the end of each of the sides I cut a cutting slot to assist in slicing the soap after it's made (completely optional).
Suffice to say measure twice, cut once and always try pieces together before you start glueing/screwing.
- Anyway whilst I suspect I could possibly have used it unlined I decided to be extra safe so stapled in a layer of builders film (basically thick plastic sheet) as a long term backup lining.
- Each batch of soap I intended to use an additional temporary liner comprising of a doubled up layer of gladwrap/clingfilm that was taped at the top and pushed into the corners so get a pretty decent fit. This proved easy enough to do and should work well.
- The moveable ends seem a great idea as I can vary my batch size from a maximum of around 2.8L (assuming 6cm height bars) to anything below. I was advised to start with a smaller batch at first as obviously it's easy to make mistakes - so essentially went with a 1/2 load only.
- I joined up over at soapmakingforum.com , very helpful bunch and actually a LOT of shaving soap making fanatics there as well.
- I had to use a special spreadsheet to figure out given the set volume of soap mix going into my set mold area (I went with 25 x 9 x 6) how much oil to use. Then from that I was able to use a lye calculator, I used soapcalc.net - to punch my variables in and get the actual recipe.
- I already had a lot of the oils etc on hand but wanted to go with something using tallow - which I feel is excellent for soaps but gets a bum steer due to a lot of folks who are drawn to soap making not liking using animal products etc. I sourced it through Woolies, is their homebrand solidified cooking fat, ~$2.75 per 500g - so very cost effective.
My % breakdown was:
- Beef tallow 50%
- Olive oil 20%
- Coconut oil 15% (ended up using refined coconut oil as Coles had it on half price a few weeks back)
- Rice bran oil (10%)
- Castor oil 5%
I added a TBS of green clay powder and used rosemary and lavender EO's to scent it. Superfatted at 5%.
- Making it was very simple. Just a matter of printing out the recipe and being very careful to measure out all the oils etc. Also being careful with the lye mixture. I didn't even bother to wear gloves but did wear some safety goggles (though I did keep a spray bottle of vinegar nearby).
- Achieved 'trace' in under 5mins, poured into the mold that was measured out to give the right internal measurements. Tapped it a bunch of times and put a layer of clingfilm over the top. Put lid on and covered in towels etc to insulate.
Will unmold and cut into ~1 inch thick bars about 18-24hrs later. Need to cure for around 4-8weeks - which is a PITA but watchagunnado.
I'd attach some pix but it's all bundled up right now. Anyway I recommend others give it a try as I made things much more complicated than needed with making the mold etc but you can use a lot of existing old containers or disposable ones e.g pringles tubes.
I just used stainless steel pots to make the lot in - can be used as normal after you've washed out properly so no need to buy dedicated stuff etc - the only thing I am keeping just for soap is an old plastic spatula - as the EO's etc will get their scent into it.
Anyway we'll see how it goes.