Reddit reviews The Player's Guide to Guitar Maintenance

Being in the Industrial Arts, you have a leg-up on most people. There isn't any reason that someone like you should be at all discouraged from moving your skills over to guitar repair--unless you desire to make a big pile of money.

In any case, there are so many free/cheap resources available these days, combine those with cheap used guitars on the market that can be purchased cheap--especially if there's something wrong with them, which is what you want.

The books of Dan Erlewine, specifically "Guitar Player's Guide to Guitar Repair", and "How to Make Your Guitar Play Great" are both very good. Erlewine is a consultant with the guitar tools and supply house Steward-Mac, and they produce many good videos on various topics (some which you can find on YouTube).

https://www.stewmac.com/

The book "The Player's Guide to Guitar Maintenance" is not super in-depth, but I do like it because of its well done illustrations and photos:

https://www.amazon.com/Players-Guide-Guitar-Maintenance/dp/0879305495

Any of the books or videos of John Carruthers are recommended (some of his videos are on YouTube). The YouTube channel for Crimson Guitars is a wealth of info:

https://www.youtube.com/user/CrimsonCustomGuitars

My favorite book on guitar electronics is a bit dated--you're not going to find the latest pickups mentioned--but it's a great primer on the subject, and you can read it free in your browswer (Craig Anderton's: "Guitar Electronics for Musicians")

https://www.scribd.com/doc/2154081/Craig-Anderton-Guitar-Electronics-for-Musicians

Also, many of the pickup makers have resources on their sites can be informative. And reading forums that are for specific makes of guitars--like the Rickenbacker forum, or the G&L forum--can often contain input from employees of those companies, so you can read what experts on the guitars have to say.

I'm not good with paint and finishes, so I'll let someone else cover that.

I recommend listening to "The Luthierist" podcast, if for no other reason than it can be encouraging to hear other's struggles in the industry:

https://theluthierist.podbean.com/

I recommend the various YouTube videos of Phillp McKnight for general guitar information:

https://www.youtube.com/channel/UCEzJtFWNg7d7TZW7K9JyXmw

I could go on for quite a while because there are some many resources--in a way, one of your biggest challenges is to find the nuggets of wisdom among the vast ocean of opinions.