First of all:
M E :) said:
For how many (roughly), say, 4x5" PCBs that bottle suffices?
Answer 1:
jlpelect5 said:
Didn't keep track but I would say a couple hundred so far.
Answer 2:
MrDEB said:
Have used the ferric chloride $$$ and NO it won't last for more than a few etchings...
Quite different answers, to put it mildly. Obviously I need the third (and fourth) opinion!
MrDEB said:
With the Muratic Acid/Hydrogen Peroxide $ you can as I understand it, rejuvenate it by adding more Hydrogen peroxide.
This is partially true (IMO). After some time of use, the HCl+H2O2 solution "becomes" CuCl2 (prevalently) solution, so later you will etch with CuCl2 actually! That solution you can rejuvenate by passing air bubbles through solution (adding fresh oxygene to the solution) - no more need for adding peroxide at all! BUT, again, I repeat, either muriatic acid + peroxyde or CuCl2 are not suitable etchants for toner-transfer, Sharpie (or Edding or so) pen - that solutions are simply too aggressive! Furthermore, on the bottle of POSITIV-20 the manufacturer strongly recommends use of Ferric-chloride! I heard from many people (also from this forum) that they actually see how muriatic acid ruins photo-resist tracks!
Also, the guys from Pulsar, recommend the"new" etching technique, with only small amount of, guess what, Ferric-chloride, very small amount is needed with sponge:
<scroll down to: "CONTACT ETCH" - HERE'S HOW TO MAKE A FAST ETCH!>
However, many people have good results with muriatic acid, but IMHO it is a big lottery!
I don't care for expensive (and good!) Pulsar's TT-Paper until I have access to 10 cents per A4 page children's gummed collage paper - it works exactly the same as Pulsar's paper, I guarantee - please see this (my) post:
<Gummed paper magic> (see also the third post after that!).
Also on ebay it is also available ordinary (not collage) gummed paper - see prices and compare! For TRF-Green there is NO alternative, and I have it, but its application is sometimes pain in the ass: it wrinkles very easy on larger boards!
Also, from my experience, TRF-Green is ALSO very sensitive to muriatic!
I like Dip-Trace, it is my second choice after Pulsonix! Also Sprint-Layout is very handy for undemanding projects. I always use copper-pour option (not just for etchant saving).
You are generally right: Muriatic acid is very cheap, allways available, transparent...
On the other hand Ferric-chloride IS very messy and stinks
, but it is not SO expensive (I can get 500g for about 4USD). There is some new tricks with citric-acid so it lasts much longer. It is also very important to make the right concentration of it! According to manufacturer, the MINIMAL concentration is 250g/L (distilled water),
OPTIMAL concentration is 1kg/L ! Maybe you use to weak solution, so it doesn't last long?
I, personally, will go to FeCl3 and sponge etching, or bubble-tank, or, much better,
foam-etching (many people didn't ever hear about that method).