Etching PCB - dealing with anhydrous ferric chloride I'm looking into PCB etching,which requires ferric chloride (There are other etchants, but they're pretty hard to come by where I live and too expensive if I can find them).
The issue is that where I live, only anhydrous ferric chloride is sold (Which is stupid. They don't even label it properly as anhydrous - got exposed to HCl fumes for 2-3 hours, thankfully the doctor found nothing abnormal with me and I got sent off with some anti allergy meds).
I'd like to know what equipment I'll need to deal with this stuff safely. I always use nitrile gloves with these, but in particular what kind of respiratory protection will I need? I plan on just having 4 PC fans blow these fumes outside the window. If I must, I will invest in respiratory protection (It's very expensive where I live, the NIOSH approved ones at least). I'm assuming a 3M 6002 will be enough.
Please keep in mind I will be using this stuff at home. If you have any suggestions regarding alternatives, do mention them. If I can find it, I'd rather use that than this.
If this isn't the proper place to ask these questions, please direct me to a place more suitable for these questions.
$\ce{FeCl3}$ ( and similarly $\ce{AlCl3}$ ) has very different properties, comparing its anhydrous and hydrate form. They cannot be easily transformed one to the other. Heated hydrate decompose to the oxychloride or oxide eventually. Anhydrate put in water undergoes violant hydrolysis.
I suggest obtaining the hydrate, or preparing it yourself, e.g. reacting of iron, $\ce{HCl}$ and $\ce{H2O2}$ ( this mixture of the 2 reagens was an alternative Cu etching solution, when $\ce{FeCl3}$ hydrate was not easily available in the communist Czechoslovakia, but is more aggressive then $\ce{FeCl3(aq)}$ ).
Another option is to let react the anhydrate with limited water outdoors and that adding concentrated HCl. For the dissolving itself it would be the best to put in directly to the acid:water 1:1, but it would develop dangerous fumes.
Avoid mixing concentrated stuff, it would turn into a chlorine chemical weapon. Start with 10% peroxide and 1:1 acid, calculate the ratio. Tune it later at will. Keep the etching solution rather mild than strong, to simulate etching performance of FeCl3. My experience with etching $\ce{Cu}$ circuit boards was that too strong solution was often etching metal under the protection layer. Be aware of proper after treatment, to prevent future corrosion.
Usual gloves, coat and eventually shield. Well vented place is needed, at least for first experiments, until you know the behaviour ( I mean rather passively - like outdoor - and just temporary for initial experiments. when it is settled, it is not much needed. ).