What etchant to use?

[Krumlink]

I have used Ferric Chloride and I hate it. It stains and doesnt work very well at all. I have seen a few methods of PCB etching, and I would want to try somthing reusable, safer, and cheaper and preferably home made .

I have seen this method:**broken link removed**

and a saltwater anode method (dont have link to that one sorry).

Any other prefered methods? I was going to pick up some muratic acid and some h2o2 today.

Reguarding the Muratic acid method, he adds h2o2 to get culpric acid, so if i just use a fishtank pump and a bubbler, would i need h2o2 at all?

 

[3v0]

It is not cheap or home brew, but I like using Sodium Persulfate. The stuff I use is by MG Chemicals and purchased from Mouser. It cost $21, and after a year I still have a bit under half left. I used mine to etch a few boards for school so yours may last even long.

It is very clean to use with little fumes and no acid danger. You still should wear safety glasses just to be safe. It does a very good job of etching at 110-120F. I etch in a Pyrex bread pan heated by a halogen work light. The pan rests on a lump so that I can easily rock it to agitate the solution. Very safe, simple, not even a thermostat.

I use between 1/4 and 1/2 inch of water in the pan with aprox 2-4 tbs of crystals. Amounts are not fussy.

The solution starts our clear and turns blue as it becomes used up. The more used it is the slower it etches. You can get a board or two extra from each batch if you are willing to spend extra time to let it etch.

When it is used up I toss it into a margarine tub where the water evaporates leaving behind blue crystals.

Evandude etches boards in a ziplock FREEZER bag
see https://www.electro-tech-online.com/threads/first-try-with-press-n-peel-blue-results.16187/

 

[Sceadwian]

Are you sure you're just not heating your bath enough or supplying proper agitation? Ferric Chrloide is reusable until it's saturated, if you're approaching mass production on a board it's best to out source, for both environmental and cost reasons. The one nice thing about ferric chloride is that you'll often be able to find a local metal finishing company that will take used sollution off your hands if you ask around. ANY saturated metal fluid especially those that use copper need to be disposed of properly even in small batches if at all practical at your location. Don't asume it's not practical until you've done the proper research.

 

[Krumlink]

I made the Muratic Acid and H202 method, and it worked GREAT! Way better than the Ferric Chloride crap that costs way much more! I made 16ounces for about 2 Dollars!!!!!! It costs $1 for 16oz of H2O2 and $5 for the muratic acid. It was awesome. As soon as I droped in a dummy sample (some thin copper wire) it dissolved the enitire 4 inch peice (24 gauge stranded) in about 25 seconds. It immedately turned green as soon as it contacted the stuff. I know what I am going to be using!!!

The end board turned out awesome. I cleaned it up with some acetone and it turned out nice and shiny. I made the board on some Flex stuff (the 3thousands of an inch stuff, the thickest of the stuff I had). I also have some more flexable than paper stuff, which is awesome. It is about as thin as tissue paper, which is pretty sweet. I cut it out really easily, and it looks awesomely awesome. I put a bunch of !DANGER WILL ROBINSON DANGER! stickers with a alligator outline

Very easy, safe and simple to make. The best stuff EVER!

 

[Dean Huster]

I'm willing to get ammonium persulfate on my fingers. How about the safety factor of the HCl acid mixture? Cheap is fine unless you acquire the nickname "Stubby" during the course of your hobby. I've never tried the mixture. What's the recipe?

A really fast-acting etchant can be difficult to use if thin traces are undercut before you can get the board out.

Dean

 

[Nigel Goodwin]

How about the safety factor of the HCl acid mixture? Cheap is fine unless you acquire the nickname "Stubby" during the course of your hobby.

A friend of mine (and one of our black belt students) had to remove some pipe at work and clean out a filter. He refitted the filter but the pipe is held on by cable ties, so you need both hands to do the cable ties, and a third hand to hold the pipe in place.

So he held the pipe between his thighs while he did the cable ties.

Pity about the concentrated nitric acid that leaked down the pipe onto his inner thighs!

Luckily it was ONLY his thighs!

They were talking skin grafts, but luckily he's a very good healer, and appears to have recovered from it fairly well.

Moral of the story - keep acid well away from any bits you're fond of!

 

[Krumlink]

Well, this muratic acid is at 32% and around 10M of Hcl. As with any irresponsible youth/bored with nobody home, I was putting sticks and leaves and grass in a small cup of it and watching it boil and dissolve other stuff

I found out that if you put more muratic acid into the etchant, it speeds it way up, but creates more fumes. It increased etching time drastically, so I am quite happy with this stuff. If I need to dispose of it, since michigan has almost no laws on harmful chemicals and stuff like that, I can *accidently* pour it into a sealed container and *accidently* put it into my trash can.

I got pictures (of unfortunate people)!

 

[monkeybiter]

I would strongly suggest that while you are using your homebrew etchant you wear goggles. You can still make robots if you're stubby or scarred, but you'll be pretty well stuffed if you blind yourself.
Nigel, did that incident happen recently? I work in the chemical industry, and I'm sure you'll agree they've got some serious control/safety problems just for that situation to arise. You wouldn't believe the paperwork I have to generate just to grant access to certain areas, let alone actually do any work once there.

 

[Krumlink]

I wear full body safety gear, so no chance (or very little) of that happening

 

[Sceadwian]

Krumlink, for gods sake don't put it in a trash can, if you're going to dispose of it in small amounts it's perfectly safe to dillute it with as much water as possible and send it down the drain, the waste water treatment plants system will take care of the rest, if it's not treated before the effluent hits a river or something it's at least dilluted to the point where it will have no real effect. This is of course only for small amounts.

 

[Nigel Goodwin]

Nigel, did that incident happen recently? I work in the chemical industry, and I'm sure you'll agree they've got some serious control/safety problems just for that situation to arise.

Yes, very recently - he's not back training yet, although he's pretty close.

You wouldn't believe the paperwork I have to generate just to grant access to certain areas, let alone actually do any work once there.

I think Jason has found a lot of paperwork since!

 

[Ang999]

I don't want to recommend something if it is total cra*. but, in theory, maybe saltwater would work. since salt is acidic, it may actually work.



(excuse my language. I am a new member)

 

[JimB]

maybe saltwater would work.

A novel approach, try it and let us know how you get on.

JimB

 

[hyedenny]

Are you sure you're just not heating your bath enough or supplying proper agitation? Ferric Chrloide is reusable until it's saturated, if you're approaching mass production on a board it's best to out source, for both environmental and cost reasons. The one nice thing about ferric chloride is that you'll often be able to find a local metal finishing company that will take used sollution off your hands if you ask around. ANY saturated metal fluid especially those that use copper need to be disposed of properly even in small batches if at all practical at your location. Don't asume it's not practical until you've done the proper research.

BRAVO!!
Finally someone else speaks up about the very real environmental issues. There are a few fools in these threads who insist that dumping copper compounds down the drain isn't bad for the environment.

I use both ferric chloride, and sometimes hydrochloric acid/peroxide. The acid/peroxide mixture is easier to see the progress on, it doesn't stain, and it certainly won't dissolve your fingers as someone else suggested.

 

[Usernametaken]

I don't want to recommend something if it is total cra*. but, in theory, maybe saltwater would work. since salt is acidic

Salt is neither acidic nor a base.
It's a salt...

 

[Pommie]

BRAVO!!
Finally someone else speaks up about the very real environmental issues. There are a few fools in these threads who insist that dumping copper compounds down the drain isn't bad for the environment.

I use both ferric chloride, and sometimes hydrochloric acid/peroxide. The acid/peroxide mixture is easier to see the progress on, it doesn't stain, and it certainly won't dissolve your fingers as someone else suggested.

Really, an old thread and you post your environmental crap again. Do some research .

Mike

 

[gophert]

I don't want to recommend something if it is total cra*. but, in theory, maybe saltwater would work. since salt is acidic, it may actually work.

Salt is neither acidic nor a base.
It's a salt...

Although Ang999 was most likely talking about common table salt, NaCl, Usernametaken, your statement sounds like you believe ALL salts are neutral (I.e. "neither acidic nor basic"). In reality, very few salts are neutral when compared to all of the salts (ionic compounds) available in a chemical laboratory storage cabinet. This assumes your definition of "neutral" is the same as the one used by the rest of the world.

Here is a general chemistry refresher for you:

https://chem.libretexts.org/Core/Ph..._Aqueous_Solutions/Aqueous_Solutions_Of_Salts

 

[Ang999]

Although Ang999 was most likely talking about common table salt, NaCl, Usernametaken, your statement sounds like you believe ALL salts are neutral (I.e. "neither acidic nor basic"). In reality, very few salts are neutral when compared to all of the salts (ionic compounds) available in a chemical laboratory storage cabinet. This assumes your definition of "neutral" is the same as the one used by the rest of the world.

Here is a general chemistry refresher for you:

https://chem.libretexts.org/Core/Ph..._Aqueous_Solutions/Aqueous_Solutions_Of_Salts

Thank goodness! maybe my "theory" wasn't bad.

 

[Ang999]

A novel approach, try it and let us know how you get on.

JimB

Maybe I should go on Amazon to find what I need to try it.
#intheory