Hi, I'm Chris; found your forum
I'm the soapmaker for our shop: cold proc; veg; essential oils, emols.
We have our veg oil blend, precise mix.
Lye in dense water solution, mix must be kept very precise, by weight from solid.
Manual mixing of tanks
Load the top. Dispense each through valves at base, easier.
Lye tank and fittings best if from a corrosion-products specialist.
Preheat in plain tank, manually transfer oils, and keep heat and precise temps in a 2nd water-jaket tank.
Most important to use a precise weighing floor scale. Must be zero set capable. Easy to read up close or over your shoulder. Quick to settle down, and clearly reproducible of each measurements. Use a scale-supply company and make sure they'll exchange it right away if there's a tech problem (rare).
Precision weight measure for lye solution for me is +/- 1 part in 292. (.34%)
Precision weight measure for oils for me is +/- 1 part in 601 (.17%).
Build a wheeled trolley for the lye tank for area cleaning.
I'll charge the lye tank bag-by-bag with lye solid, verify the weight of each to find out the over/under for the particular pallet-batch (it does vary), and adjust the water quantity to make and exactly known concentrate solution. Yes water aways first, dispense by hose. Bulk lye 2nd (measure each exactly); supplemental water 3rd. Record tank-chargings on paper.
Manually stir lye with a corrosion proof rod. Use both arms. (too thick for a paddle)
Need to use an elevated platform to stand and pour from.
Stand on the 'windward side' of the tank when mixing, you must begin the mixing in short order.
Have a powerful-enough electric air-exhaust fan to vent the building to the exterior during lye mixing. A hood would be over kill. You can turn it off after you cap the tank so you don't waste all of your air conditioning.
A large tank of lye from dry lye undergoing dissolution will release all of its heat of dissolution in just a few minutes, and become quite hot, frothy, and 'vaporous'. Heat is lost through surface area of the tank, which ratio drops with volume. So okay to go hot, but never go boiling!
Wear chemical goggles, N95 mask, Thick, long apron, rubber boots, and forearm rubber gloves (but usually I just wear the blue nitrile short gloves, better dexterity. So once in a while I do get a forearm burn or two.) You can wear a face-shield over your goggles to double up if you want.
Work near a rinse sink in case you are burned. Put white vinegar in a spray bottle too, to neutralize lye on skin if needed in a hurry. Keep the bottle within reach in the same place always, where you can find it literally with both eyes closed.
Vinegar neutralizing a lye burn hurts more, like iodine/alcohol on a cut; what did you expect?
I can run two cycles, batches of soap in a week
This week one batch, for me 11 x block molds at 55 lbs =~ 605 lbs. 1815 bars 330 ends
A big mass will keep its heat more easily for the saponification.
Manual cutting. It'll take more than a day to cut this much.
Drying rack full would be a tad over 8000 bars, ~1.3 tons (moist).
Making soap is great.
8)