thanks for the help. This site has been a big help to me as I am getting more into electronics.It is great to have a place to ask questions and get get good answers back.Thanks for the link Beenthere.I have been searching online and haven,t seen that site before.
pcb making with a sharpie
- Thread starter pkennedy
- Start date
Another side comment, usually FeCl comes mixed (it is how I would buy it). I have seen it come in powder form. It is a straight forward chemical. I'd have to research how much water to add if this was the case. Even the board shop I serviced bought it in liquid form.
@beenthere,
Can you tell us the mixing ratio, assuming it is the anhydrous FeCl3? It is a bit hard to figure out from the available information, such as 41% or specific gravity. (Yes, I know how to make a 41% solution, but that is QS to 1 L, not a ratio.)
John
Can you tell us the mixing ratio, assuming it is the anhydrous FeCl3? It is a bit hard to figure out from the available information, such as 41% or specific gravity. (Yes, I know how to make a 41% solution, but that is QS to 1 L, not a ratio.)
John
No, as I did the mixing some years ago and the stuff still removes copper (I made up some spillage; I use about 4 1/2 gallons in my etcher. Do not ask about removing FeCl stains from concrete). I seem to recall that the dry packets were sized to mix with some specific quantity of water - probably one pint.
Follow-up
Ferric chloride for etching is often referred to as 40% ferric chloride. Problem is whether that is wt/wt or wt/vol. Either convention might be used, and I could not find a site that clearly stated which convention was used (wt/wt is the answer, which is more common).
I did find references to 40% ferric chloride having a specific gravity of 1.42 (approximately).
With that information and a few calculations, here are two recipes for producing 1L of etchant from solid ferric chloride:
1) Using anhydrous ferric chloride, MW 162.2:
FeCl3: 565g
Water: 855 mL or g
Final volume should be close to 1L
2) Using ferric chloride hexahydrate, FW 270.3:
FeCl3.6H2O: 942g
Water : 479 mL or g
Final volume should be close to 1L
It has been suggested that the ferric chloride should be added to the water. That is clearly the safest thing to do, particularly if dealing with the anhydrous form, as its dissolution is exothermic. If using the hexahydrate, the order of addition does not matter, and it may be more convenient to add water to the solid in some circumstances.
John
Ferric chloride for etching is often referred to as 40% ferric chloride. Problem is whether that is wt/wt or wt/vol. Either convention might be used, and I could not find a site that clearly stated which convention was used (wt/wt is the answer, which is more common).
I did find references to 40% ferric chloride having a specific gravity of 1.42 (approximately).
With that information and a few calculations, here are two recipes for producing 1L of etchant from solid ferric chloride:
1) Using anhydrous ferric chloride, MW 162.2:
FeCl3: 565g
Water: 855 mL or g
Final volume should be close to 1L
2) Using ferric chloride hexahydrate, FW 270.3:
FeCl3.6H2O: 942g
Water : 479 mL or g
Final volume should be close to 1L
It has been suggested that the ferric chloride should be added to the water. That is clearly the safest thing to do, particularly if dealing with the anhydrous form, as its dissolution is exothermic. If using the hexahydrate, the order of addition does not matter, and it may be more convenient to add water to the solid in some circumstances.
John
DickCappels
- Joined Aug 21, 2008
- 10,185
An easy-to-get lacquer and applicator is a bottle of cheap fingernail polish.
To Bill Mardsen: It's how I started in the '60's, youngster.
To Bill Mardsen: It's how I started in the '60's, youngster.
ChrisHelvey
- Joined May 22, 2004
- 46
I thought I would add my two cents just in case someone didn't know about this:
As an etchant, I use 1 part Hydrogen Peroxide (regular drug store item @ 99 cents) to 3 parts Hydrochloric Acid (muriatic acid at the hardware store for 6 bucks.) Your first board turns the solution emerald green (cupric chloride.) It never needs to be disposed of as you can regenerate the solution as it turns brownish and less effective (cuprous chloride.) Just add more Hydrogen Peroxide or run bubbles through it for a while.
Cupric Chloride becomes the etchant and cuprous chloride the result.
Just be careful as it is a strong acid you have.
You guys probably already know about this, but I just recently learned and will never go back to the icky, smelly iron based stuff. Though it might be worth passing on.
As an etchant, I use 1 part Hydrogen Peroxide (regular drug store item @ 99 cents) to 3 parts Hydrochloric Acid (muriatic acid at the hardware store for 6 bucks.) Your first board turns the solution emerald green (cupric chloride.) It never needs to be disposed of as you can regenerate the solution as it turns brownish and less effective (cuprous chloride.) Just add more Hydrogen Peroxide or run bubbles through it for a while.
Cupric Chloride becomes the etchant and cuprous chloride the result.
Just be careful as it is a strong acid you have.
You guys probably already know about this, but I just recently learned and will never go back to the icky, smelly iron based stuff. Though it might be worth passing on.
