My experience is the opposite of this. Plain beeswax is actually quite brittle and is not sticky, so it doesn’t hold the reeds in place. Candle wax (or paraffin wax) is less brittle (though it is still brittle) and works better at gripping the reed plates. I've seen some older German made accordions where they have used it instead of the stuff you mostly see, which is a mixture of beeswax and rosin and some oil, and which Is super sticky when it’s new. Paraffin wax isn't perfect but it does sort of work. And I know of one tech in the uk who mixes beeswax and paraffin wax to mount reeds. I tried making my own reed wax for a while…which i found tricky because the rosin and beeswax melt at different temperature. After a lot of experimentation I never got the hang of it and the wax was always more brittle than I wanted it to be. Maybe the rosin wasn't the right kind. And anyway Carini sell great blocks of the genuine stuff and it’s pretty cheap, so I just use that now. And it is, as I said, super sticky.
You hit the nail on the head here! These "problem solving skills" are clearly underemphasized during the ACA courses I took. I think it's a result of the courses being taught by staff from an accordion manufacturer, not by people with 50 years of experience repairing accordions. I find that repairs often require detective skills, trying to find the cause of spurious sounds (without being able to look inside at what's happening). Especially in the tuning course module little attention is given to adjusting valves to obtain a stable note frequency that isn't (or is hardly) influenced by the volume the note is played at. Just the "tuning is always done playing mezzoforte" isn't good enough for very critical ears for instance.
