Cheep Etching solution

I thought i would share a etching solution formula i found online. it works really quick and is really cheep, but it is dangerous if you don?t follow all the safety guidelines concerning the acid. Another concern I had when considering keeping the solution to re use, was after the first use it turned a really cool lime green resembling kool-aid or anti-freeze. Last thing I wanted to do is put this stuff in any kind of drinkable container so i disposed of it.

Use Caution; muriatic acid is very poisonous both from the vapors and the acid. use gloves, eye protection and lots of ventilation etc... all metal in contact with the acid will be affected so use only plastic containers and tools i.e. brush's etc...
 
muriatic acid (available from most hardware and drug stores) and hydrogen peroxide (the same you buy for cuts and scrapes) mixing is two parts hydrogen peroxide and one part muriatic acid. this needs to be used in a very well ventilated area like outside and not in the wife?s stainless steel sink! I etched a circuit board in about 3 minutes and could see when it was time to take it out.
I used a Tupperware container, a five gallon bucket of clean water (for safety reasons), latex gloves, safety glasses and a small plastic cup. Poured two small cups of peroxide in the Tupperware container then a small cup of muriatic acid. Placed the board in the container, the liquid turns green as the copper etches away. Took it out a couple of times and dunked it in the bucket of water to make sure I wasn?t over etching.

this is the double sided board just after etching.


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thanks, love the forum, build plans and just a wealth of tips, ideas and experiences here.

VPR

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		Quote:			Posted by Eugene52
	Hello again VPR . Maybe later , if you get some free time you can explain your method AGAIN on the photo transfer or the laser print PCB prep work method [before the etching]. I think you and or Homefire posted on that several weeks ago ? Thanks Again ...........Eugene

absolutely,
I use a laserjet printer on photo gloss paper, an inkjet wont work. reason is laserjet toner is actually made from plastic and melted onto the paper with a heat roller or actual laser. to put the image on a copper board is just a reverse process. i usually darken the copy to get more toner on the paper. if the copy looks bad so will the board. prep board with scotch brite then clean with acetone or finger nail polish remover. dont use steelwool.

1. double check that you have the correct orientation of the print.
2. using a standard iron on high and no water i pre heat the board (you don?t have to pre heat).
3. place the copy face down on the copper board, be careful not to move it or it will smudge the image.
4. do not twist the iron or slide it. try to get as much of the iron on the image as possible and apply some pressure, lift it and get the rest. i do this for about a minute until i feel it is melted.
5. place the board in a bucket of water for about 5 minutes or until the paper is completely soaked then remove and peel the paper away.

The melted toner is pretty tough but can be scratched off by using to much scrubbing to get the paper off. i use my finger and rub what?s left over. check the board circuit after removing the paper to see how everything looks, if its bad use acetone remove the toner and do it again or doctor some minor areas with a sharpie or circuit pen. then i etch using the above method. drill the holes clean with acetone and iron another image of the parts on the component side.

VPR



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		Quote:			Posted by goldigger
	Proper etching fluid is ferrous chloride while muriatic acid is hydrogen chloride. One makes use of the fact the solution prefers copper ions to iron ions, while the other eats anything

I think your referring to Iron(III) chloride, also called ferric chloride, which has a two-step redox reaction to copper(I) chloride and then to copper(II) chloride. A by-product of dissolving iron ore in hydrochloric acid(hydrogen chloride in water), or of combining iron(II) chloride (also known as ferrous chloride) with chlorine
True it is more dilute and stable, not to mention hydrochloric acid is under the 1988 "United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances" because of its use in the production of several drugs. So it may be hard to find in some places, then again Gastric acid one of the main secretions of the stomach consists mainly of hydrochloric acid.

Use your imagination 

But I have to say, this topic is golden.
I'll have to try the printer thing.

        Allodium


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Allodium;

Hair splitter.... I well know there is a difference between ferric and ferrous, and here, Muriatic is a farm-use thing, however, I think muriatic is too strong to have around when you can buy sodium hypochlorite/ate, at Walmart.... or even  the toilet bowl cleaner, which I mentioned, before. Its funny, I dont remember the suppliers saying FERRIC chloride/ate. 

I saw a guy try silkscreen technique, once, without much success, because he did not have a proper silkscreen frame, nor a way to hold the pc board.... it smeared. A resist, that will set and resist acids, will not necessarily make a good printing ink... a commercial silkscreen resist would be needed. It is too expensive for a one time run of boards.

goldigger

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