First etch with muriatic acid

[MikeH]

Works awesome.  It's super cheap.  Way better than Ferric.  Waaaaay better.  For the cost of a bottle of ferric I got enough muriatic and Hydrogen peroxide to make 3 or 4 times as much etchant.  It's also clear, so you can really see the etching happen,  so you don't have to keep pulling out the board, and washing it off and checking, etc....  I did a board that was about 4" by 4" in about 8 minutes, at room temperature.  And the etch looks great too.  For those who don't know, it's 1 part Muriatic acid (the 28% HCl kind, availiable at hardware stores), and 2 parts hydrogen peroxide (the 3% type, availiable at any drug store).  It does make more fumes though, but I found that a fan blowing out the window in my bathroom to be sufficient ventilation.  And when mixing, always pour the acid into the peroxide.  Doing it the other way around can cause a dangerous reaction.

[markm]

Interesting.
Any Pics? 

[Meanderthal]

 Has anyone tried this without the H2O2? Just curious... I've gotten muriatic acid all over lots of things(including myself), but never seen for myself how it specifically reacts to copper. And I've never diluted it with peroxide, just water.

It'll etch aluminum for sure.

[QSQCaito]

That's great. Muriatic Acid is what you put into swimming pools to regulate pH.It might be faster and all the stuff, but you can touch Ferric, touch Muriatic Acid and you will regret it, a lot lot.

Bye Bye

DAC

[MikeH]

No pics unfortunately, and I alrealdy populated the board.  But I'll post some pics of the next board I etch.  I was surprised at how easily I could find the muriatic acid.  I thought it would take some searching but the first hardware store I called knew exactly what I was talking about and had it on hand.  I think people use if for their pools or something??  It's like 5 or 6 bucks a gallon, 2 or 3 for a pint.  And Hydrogen Peroxide is pretty cheap too.  2 to 3 bucks a pint, I think.  I'm guessind the H2O2 is there to act as a buffer, to keep the reaction from being too fast, which might produce a lot of extra heat and more concentrated vapors too.  Although I think you'd have to be etching a lot of metal for it to get hot enough to melt your tupperware!

[MikeH]

That's great. Muriatic Acid is what you put into swimming pools to regulate pH.It might be faster and all the stuff, but you can touch Ferric, touch Muriatic Acid and you will regret it, a lot lot.

Bye Bye

DAC

Yeah, definately wear some rubber gloves.  Although I wouldn't touch Ferric either.  I think that's also why the H2O2 is there; to make it a little safer to handle.  If you mix a 28% HCl mixture with 2 parts of basically water, you get about a 10% HCl mixture.  According to most definitions of "Caustic Substances" containing HCl, a concentration of 10% or more is "Caustic" and considered dangerous.  So it's definately dangerous, but on the low end of the spectrum.

[zjokka]

Has anyone tried this without the H2O2?

Yes! But I used pure (40%) HCL which is very potent and smokes terribly. Next time I'll dilute it with water. The problem with etching aluminum is that it needs very very very little time and etchant. If you'll overetch the toner will get eaten out.

This is a very useful etchant thread: check it out there's a lot of info there.

http://www.diystompboxes.com/smfforum/index.php?topic=52118.0

zj

yeah, I always wear industrial gloves.

[Meanderthal]

touch Muriatic Acid and you will regret it

So it's definately dangerous, but on the low end of the spectrum

I'd put it VERY low. Don't let that sticker with the disolving hand panic you.

Shucks, it only hurts when it gets in your eyes or a cut. It won't disolve(or etch) you. If it did that you'd already be long gone, because it's in your stomache right now...

I used it by the 55 gallon drum to clean brickwork back when I was a mason. Got it on every inch of my hide many times. It's relatively benign, nothing like battery(sulphuric) acid. But, I'm just speaking from lots of experience... on paper for all I know I might be long dead from it.

I know I'm sure not gonna ever be afraid of it...

pure (40%) HCL which is very potent

Hell yeah, that's more like something worth worrying about! At that concentration... Personally, the first thing I would do is mix that 50/50 with water. Then it'll be more like the average storebought(and a bit potent even then, but at least not dangerous).  Where on earth did you find that vitriol anyway? That's industrial strength stuff there...

[QSQCaito]

I'm used to the Muriatic Acid use for swimming pools, that will hurt and be annoying if you touch it.

I've several times touched Ferric and nothign happenned.

bye!

DAC

[Meanderthal]

 Come to think of it, that's true, the few times I etched a pcb it was with FeCl and I didn't wear gloves, held the pcb to rinse it off, no problemo. I'm not worried about something that takes 20 minutes to eat away that smidgen of copper, not under running water anyway. I'm more worried about the leftover tray of gook... and the fact that I already rinsed a little down the sink(all pvc plumbing) and into my septic tank. It's one thing to get acid on your skin and rinse it off, it gets bothersome a couple years later if it gets in the ground water in anything like a large quantity.
I'm not worried about drinking it later... my well's 550 feet deep(primary, not ground water), and I live on a hill. It's other folks who rely on the ground water and springs around here to be clean and pure who I'm thinking about...
And I know that muriatic acid won't hurt a thing... not well diluted. I've never seen it kill plants, but we always used lots of water rinsing(diluting), no harm done, so I'm just going with what I know.

[MikeH]

And for sure everyone is going to have a different reaction to it.  Some people (like me, and it seems meanderthal too) have pretty tough skin, but other people have very delicate skin that can be burned by acids quite easily.

And the etchant isn't what's bad for the environment, it's really the metals in the used etchants.  Copper is not as bad as aluminum, but it still hangs out and can poison you if you're exposed to enough of it.

[blanik]

It does make more fumes though, but I found that a fan blowing out the window in my bathroom to be sufficient ventilation.  And when mixing, always pour the acid into the peroxide.  Doing it the other way around can cause a dangerous reaction.

usually the most dangerous stuff is the one you can't smell (quote - I found that a fan blowing out the window in my bathroom to be sufficient ventilation-)... not smelling it doesn't mean the ventilation is OK, the safest bet would be to do it outside, prepare many PCBs and doing a whole bunch of them in one session outside (and get some glasses!)

geee i feel like such a nerd saying that... 

but since i've been doing the paramedic thing, i've seen so many people hurting themselves doing home stuff (my all time favorite was the very cute 28 years old girl who opened a tube of crazy glue and the pressure of pulling the top off, sprayed the crazy glue in her eyes and the reflex she had was closing her eyes, so her eyelids were actually glued shut...    my knees get soft everytime i think about that one)

R.

[e178453]

Gonna throw a little cold water here guys and suggest we leave chemistry to the chemists, which I am definitely not.  Do know that not all acids act or react in the same manner on the same materials.
Considering what I've spent on parts, boxes, chassis, tubes, books and so on, a quart jug of Ferric Chloride isn't going to break me.
Anyway, be careful!
scott

[markm]

Gonna throw a little cold water here guys and suggest we leave chemistry to the chemists, which I am definitely not.  Do know that not all acids act or react in the same manner on the same materials.
Considering what I've spent on parts, boxes, chassis, tubes, books and so on, a quart jug of Ferric Chloride isn't going to break me.
Anyway, be careful!
scott

Agreed!

[boyersdad]

Hmm, this may be the way to go to practice etching enclosures. In a garage with the doors open of course

[John Lyons]

I do the HCL H202 thing as well. I mix it 3 parts Hydrogen Peroxide (3%) and 1 part Muratic Acid.
Just make sure your toner is thick of you will eat the copper through the pin holes and the toner will fall off mid etch!
I've etched as around 40 degrees or colder ( basement in 20 degree weather) and it still works well.
Heat does not seem to be an issue.

John

[Ronsonic]

I've also been using the hydrochloric / peroxide mix. No real problems. Almost scary how fast it works, but no problems with undercutting or anything.

Ron

[Paul Perry (Frostwave)]

Muriatic (hydrochloric) will attack aluminum and zinc without hydrogen peroxide.
But for copper, you must have the hydrogen peroxide mixed in. Hydrochloric will make copper shiny, but not dissolve it by itself.
Hydrochloric is called "spirits of salt" in some countries.
I think "muriatic" means "relating to the sea", so called I imagine because of the chloride connection, as in common salt, from the sea.

[Meanderthal]

 Thanks, that's what I was wondering about!

[GibsonGM]

I tried this on a scrap piece, just wrote my name on it with sharpie.  1 layer of sharpie wasn't enough, and I ate most of it, lol...of course, for the first 3 minutes nothing much happened, so I added about 3x more acid than recommended!!    Next time I'm following the suggested proportions & use some patience.  The solution turns blue, which does let you know the copper is coming off.  I feel confident enough with this stuff so that next time I etch a board I will use this technique. 

So, my vote is stick to the 3:H202 to 1: HCL.  Like Meanderthal, I was a bricklayer/stone mason for like 15 years.  We use the 20% +/- stuff to clean masonry all the time, and it's more of an irritant than a sci-fi dissolving potion.   Bad for lungs and eyes.  If you get any on your hands, rinse it off thoroughly. It will itch first to let you know it's there 

To neutralize it, add baking soda!  Then it's safe other than copper gunk (metals) suspended in the goop that'll be left.  Go easy, wear gloves & work slow, ventilate and you should be just fine 
And use patience or you'll have a piece of phenolic board with no copper on it!!  lol