You use photosensitive boards or do you spray on positive 20 or other UV-sensitive resist?
I use pre-made boards from Bungard.
I have tried to buy some, much of them have gone old before I got them. Is there any other method to check, except to exposure, develop and etch and then try to figure out which step went wrong?
The story, as far as I can tell, is that they are forced to print a shelf date on the boards by regulations. In fact, they seem to hold for many years with no problems. Mine did, I'm sure; I have not tracked how old my boards are, but I have certainly used ones of 5 years or older with no noticeable difference.
Has anybody tried toner transfer/laminator method?
I've tried it and found it as hit-and-miss as the other people here.
Really, the NaOH/FeCl3 method is not messy at all. If you are able to pour a liquid from one container into another without making big splashes everywhere, then you'll be fine. Sure, those are chemicals, but only mildly dangerous to humans. You won't get blind from fumes or destroy your lungs or something like that. You can store them indefinitely in plastic containers with no risk of them breaking (check the data sheet for which kind of plastic; I got my containers in a local apothecary when buying 2 liters of aqua dest there, for free ;) ). The dangers appear when you simply pour the used stuff in the toilet (especially the FeCl3 - I have heard that the utilities can track that and you'll get really punished, and the ground water will go to hell ;) ). You can use and re-use the FeCl3 a very long time though, it is very benign. The other danger is of course to clothes, and the FeCl3 will - duh - etch metal, so don't use it in the kitchen in the good stainless steel sink or the wife will put you in pain.
All should be pretty obvious. Eye protection and simple gloves should be standard, no questions asked.
There *are* other chemicals that can be used for PCBs which *are* indeed very dangerous indeed. That's why I use NaOH/FeCl3. The FeCl3 step takes a long time (can be like 30-45 minutes) at room temperature, but that's fine with me.
All of those parts are easy to source and cheap (like 1-10€ cheap). The printer is kind of important though; I assume not every printer will give good results on transparents. A slight cloudiness does not hurt, but if there are holes in the print, you will get holes in your copper. Mine cost < €100. And you can use it for standard printing as well, so I don't count it as investment at all.