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Cheap and good PCB etching solution.....

Discussion in 'Electronic Projects' started by Rolf, Aug 24, 2006.

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  1. Rolf

    Rolf Member

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    The etching solution is made by adding 1 part Muriatic Acid (the common kind that's sold in hardware stores, about $5.00 gal.) to 2 parts Hydrogen Peroxide (the common 3% kind that's sold in dollar stores & drugstores for $0.50 a pint)

    Warning!!!!!!!!
    Mixing is a hazardous process (add acid to the peroxide, not the other way around!)

    The board pictured below was etched in five minutes at room temp.

    [​IMG]
    2.75x1.30"​

    For more info. go to:
    http://www.pbase.com/sinoline/pcb_experiments

    Question: To save Press-n-Peel someone talked about taping it to a regular sheet of paper. I have been reluctant to feed tape through my laser jet. Any comments?
    .
     
    Last edited: Aug 26, 2006
  2. Hero999

    Hero999 Banned

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    I like your cheep etching solution.

    Press-n-Peel is a waste of money, I just use ordinary magazine paper. Just print your circuit onto it, iron to a clean piece of copper clad board and wast it off with water.
     
    Last edited: Aug 25, 2006
  3. Rolf

    Rolf Member

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    The etching solution is not really mine, I am just trying to get the word around. I should have mentioned that the Hydrogen Peroxide is only $ 0.50 a pint.
    That works out to about $ 13.00 for three gallons of etching solution. And no shipping because it is available locally, even in a little hick town were I live.

    "Press-n-Peel is a waste of money". Not if you tried many of the others with very limited success and a lot of frustration. Maybe there are differences in the different manufactures toners?
    No frustration is worth a lot to me.
     
    Last edited: Aug 25, 2006
  4. dave

    Dave New Member

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  5. Hero999

    Hero999 Banned

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    Heck, I use photo resist board for real PCBs, it doesn't work out that expensive, it's probably cheaper than Press-n-Peel.

    It's easy to build a UV exposure, the cheapest way is to lay your board with the artwork on top on a table held down with a peice of glass. Use compact black light for the UV source, the easiest way is to put it in an old desk lamp and direct the beam at your PCB.

    http://www.maplin.co.uk/Module.aspx?ModuleNo=33124&criteria=UV&doy=25m8

    I know there are probably cheaper places to buy these from and don't use the incandesant type they're crap and don't last for very long.

    Look, here are some cheaper alternatives:
    http://www.blacklight.com/items/FTBPESL13T-BLB
    http://www.bulbman.com/index.php?main_page=product_bulb_info&cPath=4351_8839&products_id=11675 - needs a holder with ballast though.
    http://www.doityourself.com/invt/0307207
     
    Last edited: Aug 25, 2006
  6. bobledoux

    bobledoux Member

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    I've had great luck with the Pulsar.gs paper. SMT's with .010 inch traces work all the time, when using a cheap heat laminator. I also use ferric chloride rubbed on the board with a small sponge for etching.

    I have enough junk. I don't need more specialized equipment to do basic boards.
     
  7. Oznog

    Oznog Active Member

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    It's cheap and works, but muriatic acid is pretty darn strong even at 1/3rd concentration. Mixing is a hazardous process (add acid to the peroxide, not the other way around!).

    Actually there is a guy on eBay who sells bulk ferric chloride chunks in 10 lb lots for $40, shipping included. Etching solution actually takes quite a bit of solid per liter, but $4/lb is pretty darn affordable. You might want to find somebody else in town to split this much material with.

    http://search.ebay.com/search/search.dll?cgiurl=http%3A%2F%2Fcgi.ebay.com%2Fws%2F&fkr=1&from=R8&satitle=ferric+chloride+&category0=
     
  8. Hero999

    Hero999 Banned

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    Wikipedia says otherwise.

    http://en.wikipedia.org/wiki/Piranha_solution#Preparation

    Which way is the safest, acid to peroxide or peroxide to acid?

    You could always glue it using a glue stick I suppose. By the way (I can't remember if it was you) said they have had problems printing on magazine paper. They's said it got jammed in the printer. Well you could always try glueing it to a nomal piece of A4 paper.
     
  9. CRayD

    CRayD New Member

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    I've been using this solution since Moses was in short pants, but I would add a few comments. The fumes are TOXIC!!! do the mixing and etching outside!! and do not breath the fumes. Heating the solution to about 100f will speed up the etching dramatically. Also using a bubbler will speed up the etch and even it out across the PCB. The solution saturates rapidly, figure 1 oz. solution to 1 sq.in. of 1 oz. copper. The solution can't be easily rejuvinated. The soution will turn a pale green (the dissolved copper) as it saturates. Discard the used solution diluted 1 to 5 or better in water with a couple tablespoons of BiCab down the toilet.
     
  10. evandude

    evandude New Member

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    I'm one of the people who recommends that. I just use normal clear/scotch tape and it's never shown any signs of melting or anything. It certainly extends the use of a sheet of press-n-peel... personally I do a lot of small boards and I can often get dozens of boards out of a single sheet, and at around $1.50 a sheet that makes the cost of the press-n-peel practically negligible in my opinion.

    I've become interested in CuCl2 + HCl etching, as seen at: http://members.optusnet.com.au/~eseychell/PCB/etching_CuCl/index.html
    That formulation has the advantage of being regenerable by simply bubbling air through it, and at most occasionally adding some water or more (cheap) acid. The hard part, as I gather from that page, is making the solution in the first place, as you need to purchase or make the CuCl2, and it can be very expensive to purchase, at least from chemical supply places. However, I found both Copper (II) Chloride and Copper (II) Oxide for sale at a fireworks supply place (skylighter.com) very cheaply (less than $10 a pound). I would like to talk with someone who's a bit more knowledgeable about chemistry before getting into this type of etching (for safety guidelines, and to make sure I know exactly how to monitor and regenerate it, so I don't ruin it), but it definitely seems appealing never having to throw out my etching solution, instead just being able to keep regenerating it, even if it means I have to put in a little more effort to storing and regenerating it.
     
    Last edited: Aug 28, 2006
  11. Rolf

    Rolf Member

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    Thanks, I'll try the tape, it will probably save me about 50% that is now going to waste.
    I agree that Press-n-Peel is a bargain, got mine for $ 1.00 / sheet but I had to buy 30. So now I have enough for a lifetime.
     
  12. evandude

    evandude New Member

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    Another tip for the tape method:
    the general method is to print the pattern on plain paper, then tape the PnP on, and print again; this way you can cut the PnP to just barely larger than the pattern and have very little waste. But, that means the first pass is a pretty big waste of toner. When I am doing designs that have a lot of copper area (and thus use a lot of toner) I usually open up the pattern in an image editor and change the color to a very light gray and print that the first time, or quickly draw an empty rectangle the size of the pattern and print that the first time.
     
  13. Rolf

    Rolf Member

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    Simpler......

    To save toner; it is simpler {for me (when using PCB123)} to just draw a rectangle around the traces, then delete the trace layout. Then print just that layer, no need to go to a separate program. Lastly re-load the trace file and print your p-n-p.
    But for small board I don't even bother.
     
  14. jolino

    jolino New Member

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    Hi Rolf,
    I use "acetate" (A4 transparent film) are years on my HP1100 and no problem until now.

    Regards
     
  15. jagrolet

    jagrolet New Member

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    I have been using regular "Scotch Tape" for years to get the most out of my Press & Peel (the same method as "evandude"). I have never had a piece stuck in my laser printer or even had a piece come loose from the paper and Press & Peel. Ill continue using this method, but Im definately going to try the Muriatic Acid & Peroxide instead of the expensive Radio Shack ferric chloride. Man are they proud of that stuff.
     
  16. muki55

    muki55 Member

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    cool good etch
     
  17. sparthacuz

    sparthacuz New Member

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    many many thanks man!!

    simple but yet effective! you just saved my ass man. my medical officer and our janitor to include my commanding officer said how the hell did i etch the circuit without the procured solution?! thanks....
    :)
     
  18. Rolf

    Rolf Member

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    There must be more to this story than you are telling us, sounds interesting, please fill us in.
     
  19. Pommie

    Pommie Well-Known Member Most Helpful Member

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    When diluting acid, the rule is "do as ya outa, add acid to water". An even simpler way to remember is to think how hard it would be to add swimming pool water to 5 liters of acid. BTW, this doesn't really matter with HCl but with H2SO4 it's a different matter, add water to conc sulphuric = steam explosion and you get to wear the acid.

    Also, if the CuCl method works then the first time you use HCl + H2O2 the end product is CuCl. Isn't it?

    Mike.
     
  20. Pommie

    Pommie Well-Known Member Most Helpful Member

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    After thinking about it, I'm very dubious about the copper chloride method. If the method worked then the HCl + H2O2 method would keep working as the spent solution contains CuCl2 which should get consumed to produce CuCl which is insoluble (1.5g/Ltr). People who have tried this report a green spent liquid which suggests CuCl2 does not react any further.

    Mike.
     
  21. evandude

    evandude New Member

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    http://members.optusnet.com.au/~eseychell/PCB/etching_CuCl/index.html

    That site has about all the information I think you'd need on the process. I also came across a PDF file that was some sort of information sheet about this process which is used in industry. I'm not an expert on the subject, but he does mention other factors in the process that would affect the etching ability of the Cupric chloride etchant, perhaps there's something else going on that's keeping it from working.
     
    Last edited: Oct 22, 2006
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