CCL Blue vs Ferric Chloride Etchant

[Monkeh]

That first pack of FeCl₃ will last you a long time.

Wear gloves. Really. It stains everything.

[Mechatrommer]

we'll see about that

[MagicSmoker]

...hydrochloric acid is still nowhere to be found unless from usa, german or romania at premium price + shipping. i'm not going to buy that corrosive and risk a leakage in an airplane.

Check the pool section of a hardware store, or, of course, a pool supply store. Hydrochloric acid is used to lower swimming pool pH here, and I have to think the same market forces would prevail in Malaysia (ie - HCl is cheap and gets the job done).

[CatalinaWOW]

Be sure to look for alternate names for hydrochloric acid.  Here in the US you can't find hydrochloric acid anywhere except chemical supply houses at a premium price.  But it is widely and cheaply available at swimming pool maintenance places and hardware stores under the name muriatic acid.  Other names I am aware of include "spirits of salt" and "acidum salis".  I am sure there are others.

[BrianHG]

Ferric chloride at 70-80 deg C will etch more copper, faster (like a few minutes), with more consistent speed.  However, at this temp, there are fumes and they will damage/corrode exposed metals in you work-shop if you don't have good ventilation.

Oh my. I've never used ferric chloride hot like that. Always at room temperature, or slightly warmed to 30 C or so. I fear to think how it would behave if you make it as hot as that.

45 seconds to etch a PCB!
Instead of a circulation pump, I would just wiggle the PCB for the 45 seconds & voila, perfect PCB.
I'd do 1 at a time, though, this would slow down to 1.5minutes after ten double sided 12inx12in pcbs before I started using GND pours everywhere.  Then, it took around 50 PCBs before it even began to slow down to 1.5 minutes per PCB.
(You can tell I'm impatient...)

[BrianHG]

Another thing I noticed about ammonium persulphate crystals etching.  The slightest scratch on your protective coating would etch.  Seriously, I'm talking about having a trace clearance on the scale of 1 mil, the crystals would slightly over etch making the opening an extra 1/2 mil on each side resulting in a PCB with a 2mil gap, no shorts.  Ferric chloride didn't have this fine guaranteed clearance.  I believe it has to do with the viscosity difference of the 2 fluids.  Maybe lower viscosity ferric chloride mixtures exist.  Raising it's temp did make it flow much easier...

Once again, remember to copper fill all unused areas of your PCB, extend the life of your etchant chemicals.
Help minimize the impact on the environment with this simple trick and save yourself some money as well.

[KL27x]

is it wise to buy 1Kg dry FeCl3?

"Dry FeCl3" is an oxymoron. It's extremely hygroscopic. As soon as you open the package, it will be a sticky-wet, staining, semi-solid 1kg clump. Or more likely it will already be that way when you buy it. And despite it dissolves quite slowly, it creates so much heat that you must go even slower. So it takes forever and the FeCL powder will stick to everything. Trying to do this "neatly" is quite a pain. Liquid ferric chloride is easier to handle. If you have easy access to muriatic acid and powdered rust, mixing these together makes the same thing without dealing with "dry FeCL3." And the red rust will dissolve pretty much instantly in the acid.

Muriatic acid alert: In the US, Home Depot is carrying only this stuff by Kem Tek that masquerades as muriatic acid. If you read the ingredients, it lists 15% HCl. And 85% "not suitable for spray adjunctive." Whatever that means, it does not mean water. This stuff ruined my etchant.

Back to OP, ferric chloride keeps fine in a sealed bottle. But if you want to get the most out of it, you also want some muriatic acid. When it slows down, adding a little acid will make it work a bit longer. And when you get a lot of copper in it, aerating it will help. If you get a proper bubbly tank going, you can use it indefinitely; just add some acid and water when it clouds up.

[Mechatrommer]

hi again. my FeCl3 "humid" powder has arrived. and now i mixed 140g powder to 500ml water in plastic container. it got warmer i guesstimate about 40-50degC, even now after 30 minutes its still warm, did i do something wrong? is there some reaction going on that will screw my mix few weeks after this?

[DTJ]

No, releasing heat as it dissolves is normal.