Luc
October 13th, 2002, 01:55 PM
I will try to describe how I etch my PCB's.
25 years ago I also used the ferrochloride stuff until I found a better and much faster way.
I am not sure if the names for the chemicals are correct but I will try my best.
Once the PCB is ready for etching you need 3 products:
1: simple water (from the tap)
2: "salt acid" solution, this is used to remove chalk deposists from "pass thru" water boilers and also to remove cement traces from floor tiles and a lot of other applications. You can get it from most "do it yourself" stores.
3: Perhydrol, this is a more pure version of the "oxygen water" used to clean infected wounds etc.. You can get it at the pharmacy.
If somebody knows the correct English terms for these, please correct me.
The salt acid is the effective copper removing agent, the perhydrol is the activater to make it go quickly.
How to do it:
Put something like 5cl water and 5cl salt acid in the tray (must be plastic or so, not metal obviously....). Put the PCB in this solution and the copper will get a darker color, then add a little (1-2 cl max!) perhydrol and gently shake the tray, you could see some bubbles coming off the PCB.
You can add more perhydrol to let it go faster but be carefull to not use too much, if it goes real fast it might etch under the photoresistive layer if you don't remove it fast enough.
When etching is done rince it off immediatly and torouhgly with water .
This way etching is a matter of a few minutes with some experience.
Thake care with this solution as it might burn skin and clothes, the used solution now also contains copper besides the other harmfull products so you should dispose of it in a nature friendly matter, in Belgium we have dedicated locations where we have to deposit these kind of things.
I am of course not responsable for eventual accidents, pcb's with no copper left etc... :D
25 years ago I also used the ferrochloride stuff until I found a better and much faster way.
I am not sure if the names for the chemicals are correct but I will try my best.
Once the PCB is ready for etching you need 3 products:
1: simple water (from the tap)
2: "salt acid" solution, this is used to remove chalk deposists from "pass thru" water boilers and also to remove cement traces from floor tiles and a lot of other applications. You can get it from most "do it yourself" stores.
3: Perhydrol, this is a more pure version of the "oxygen water" used to clean infected wounds etc.. You can get it at the pharmacy.
If somebody knows the correct English terms for these, please correct me.
The salt acid is the effective copper removing agent, the perhydrol is the activater to make it go quickly.
How to do it:
Put something like 5cl water and 5cl salt acid in the tray (must be plastic or so, not metal obviously....). Put the PCB in this solution and the copper will get a darker color, then add a little (1-2 cl max!) perhydrol and gently shake the tray, you could see some bubbles coming off the PCB.
You can add more perhydrol to let it go faster but be carefull to not use too much, if it goes real fast it might etch under the photoresistive layer if you don't remove it fast enough.
When etching is done rince it off immediatly and torouhgly with water .
This way etching is a matter of a few minutes with some experience.
Thake care with this solution as it might burn skin and clothes, the used solution now also contains copper besides the other harmfull products so you should dispose of it in a nature friendly matter, in Belgium we have dedicated locations where we have to deposit these kind of things.
I am of course not responsable for eventual accidents, pcb's with no copper left etc... :D