Put hard numbers on the first 18 months because if they aren't worth the $12.00 it's best for all involved if they move on to a job they are better suited. I would be very carefully how I presented the other rungs of the ladder so as to not give false impressions that this is where they will be or should be in X number of months/years.
Like Garlicdude I prefer self-paced training and when they are ready they should move on. Having said that however there should still be a minimum number of hours or days spent in various departments. This is manufacturing, the day to day operation is often repetitive and at times just plain boring but they are tasks that have to be performed so you don't need to load a shop full of ADD.
Spell it out, what you are doing for them and what they are doing for you. A great opportunity for the right person/s, especially for someone that can't afford to pursue higher education. A degree could cost a few hundred thousand over a few years or they can work with you and earn while they learn. At the end they would be earning comparable wage or more than entry level college grad. That is a huge swing with no incurred debt or student loans to pay off after they graduate.
If it is a certified apprenticeship program the apprentice will work minimum eight hours a day paid and go to school four hours, two or three times a week unpaid. Doubt you can do same if it is on your property and not a formal program, not sure how it will apply if you give them homework, check local labor laws. But your costs, risk can be limited and spread out over time.
Your agreement should have a 30-90 day trial period if local law allows it. Spend a day of introduction, orientation and safety for their first assignment before letting them loose.
First few weeks of janitorial duties may be six or seven hours a day work and class for the remainder of eight hour shift. First classes Safety, proper use and care of tools, and specific training for what ever department/duties they move to next.
He did approve the project so he must believe there is something positive to it.
I have seen management inflate the cost of training, what you can do to help him is nip it in the bud, give him the numbers when you finalize the plan, don't let him/them guess they will always be too high.
Paying a trainee $9.00 hour does not mean it costs $360.00 week for training + materials + equipment + your salary.
If trainee makes $9.00 hour to start it isn't costing $360.00 a week to train. They are working for the company and it is benefiting whether they are moping floors or cleaning sump tanks it's jobs that have to be performed.
If classroom instruction is 5 hours a week then you can say it cost $45.00 but not if they are making $9.00 hour and you are paying others $12.00 hour for the same job. The disparity in pay IS paying for the training and may actually equal ZERO cost to the company. You would have to track some measurable's to verify real costs of training vs. benefits to the company.
Operating a machine yes they will take a little more supervision but that is why there is a disparity in pay between a trainee and experienced operator. Repairman's helper, Machinists helper, Plant Maintenance helper same thing.
I assume you are on salary, you get paid to do a job no matter how many hours a day or days in the week it takes you to get your job done. That makes you (IMO) a fixed cost, company overhead so to speak so your salary should not be part of the equation. Also I believe you are the type person who for every hour you spend at work on this project you spent 5X that amount on your "off" hours.
I am wondering if there are not current employees that may want into your program. That's the only real snag I see that hasn't been touched on so far. Excluding current employees and not offering them a chance could cause some internal resentment and festering issues over time.
-- Tom