Who etches photoresist PCBs?

[shumifan50]

Look on ebay there are some relatively cheap exposure units that use LEDs available. I never had great success with ironing off the toner onto the PCB and when the circuit gets a bit more complicated it becomes impossible to repair breaks in the tracks. The fluorescent tube units are expensive as the tubes are expensive here in the UK and each unit normally have 5 or 6 tubes.

 

[TTL]

Yup, that's what I've heard as well; the UV-exposure method being more accurate and better than the toner-transfer method.
I just had a look at eBay and found this 20x15cm PCB capable LED UV box for UKP 49. If it actually works it's worth considering, but I might be making some larger PCBs as well, which is why a fluorescent tube box might be better. As for the cost: aren't these normal fluorescent tubes? I thought someone said normal tubes could be used, but perhaps with longer exposure times. If we're not talking hours of waiting I don't mind waiting a bit as this is a hobby.

Chopnhack: impressive video! Makes it look so easy. Yes, I do have a clothes iron but you're right about swimming pools not being plentiful over here, and I doubt I can just go out and buy acid over the counter (with small kids in the house I'm not too keen about getting that stuff either).

 

[chopnhack]

Chopnhack: impressive video! Makes it look so easy. Yes, I do have a clothes iron but you're right about swimming pools not being plentiful over here, and I doubt I can just go out and buy acid over the counter (with small kids in the house I'm not too keen about getting that stuff either).

LOL, i thought as much. I will tell you that the acid is a bit nasty, must be used in a well ventilated place as it fumes - its about 31% concentrated. I like the fact that the copper precipitates out of solution so that the acid can be reused - less waste (or so the poster said). I would recommend a respirator when using the acid. I am going to try the clothes iron method myself and I will post results ;-)

 

[BobK]

I just made my first board with a photo-resist, and it came out great the second time (I did not develop it long enough the first time). See here:

https://www.electronicspoint.com/threads/photo-resist-pcb-help.268585/#post-1609340

I bought an exposure kit from MG Chemicals for $55 and it turned out to be nothing more than an under kitchen cabinet type fluorescent fixture with a 15W daylight bulb, two metal brackets to stand it at the correct height (about 5 in), and a sheet of acrylic. Their suggested exposure of 8 minutes worked perfectly. You could probably get these things at Home Depot for a lot less.

Bob

 

[chopnhack]

Bob, do you think that this method is more accurate than the steam iron method?

 

[BobK]

Far more accurate that I ever got with toner transfer. I would almost always have broken tracks and could not get nearly as good resolution with toner transfer. This board had no issues at all and all of the tracks and pads were very sharp and clean. Of course the pre-sensitized boards do cost more. That is the only drawback I see.

Bob