Alternative PCB Etchtants

kf4zht · Sep 20, 2007

I have several PCBs that I need to etch with the toner transfer method. I went to RS to get ferric chloride and was informed that they no longer carry it due to lack of sales. I am in Statesboro, GA which doesn't have much of anything not related to the college or farming. What are some other chemicals that will etch PCBs.

I have heard of the Muratic Acid and Hydrogen Peroxide. I can get Muratic acid at lowes, but only in 2 gal quantities. I would prefer something a little less.

DonShock · Sep 20, 2007

Try calling any local water supply plants. We use ferric chloride, 100s of gallons per day, to treat lake water and make it into drinking water. There are several different chemicals that can be used for this purpose, so your local plant may use something different. But ferric chloride is one of the main chemicals used so they may have large quantities on hand. Now, whether you can talk them into hooking you up with a quart or two might be another issue. Unfortunately, the hazmat shipping issue prevents me from being able to mail you a bottle.

doc_felixander · Sep 20, 2007

Sodium persulfate is quite common here. It's not really 'green' (you aren't supposed to pour it down the sink) but it works great at lower temps (40-50° optimum) and gives much better results (less underetching). Ammonium persulfate should work, too.

Steve K · Sep 21, 2007

Try some of the mail-order houses.

For instance, Mouser sells some....
http://www.mouser.com/search/ProductDetail.aspx?R=415-500MLvirtualkey59020000virtualkey590-415-500ML

or, goto:
http://www.mouser.com/
and search for this part number: 590-415-500ML
It's a half liter, and sells for $6.41. Not that bad of a deal. Shipping will increase the price, so you may also want to pick up other supplies at the same time (blank copper clad board, assorted IC's, etc.)

I've got a bottle of the Radio Shack etching solution, and it worked fine. Of course, I bought this 5 or 6 years ago, when R.S. still pretended to sell parts to hobbyists.

good luck,
Steve K.

robk · Sep 21, 2007

I use Ammonium Persulfate (made by MG Chemicals) available from Circuit Specialists. It's a bottle of crystals, so you mix it with water as needed. I usually mix a quart at a time, as the shelf life is about a month or two once mixed - crystals (dry) seem to last for years in a sealed bottle. It is nowhere as nasty as ferric chloride, it only smells bad if you overheat it. Works fairly fast at 100 to 120 degrees F, only problem I ever had was it will bleach fabrics - so don't wear your favorite jeans when using it.
A bottle of crystals goes a LONG way if you mix just what you need for a few boards. The solution turns blue when exhausted, but you can tell when it slows down.

Rob

kf4zht · Sep 21, 2007

robk said:
I use Ammonium Persulfate (made by MG Chemicals) available from Circuit Specialists. It's a bottle of crystals, so you mix it with water as needed. I usually mix a quart at a time, as the shelf life is about a month or two once mixed - crystals (dry) seem to last for years in a sealed bottle. It is nowhere as nasty as ferric chloride, it only smells bad if you overheat it. Works fairly fast at 100 to 120 degrees F, only problem I ever had was it will bleach fabrics - so don't wear your favorite jeans when using it.
A bottle of crystals goes a LONG way if you mix just what you need for a few boards. The solution turns blue when exhausted, but you can tell when it slows down.

Rob

Sounds like what I need. I only need to do 3-5 boards right now, but something I can leave on the shelf, and won't leak would be fine to keep long term.

I do need to get around to building a heater/bubbler tank for etching. Right now I do the tupperware and swirl by hand.

PhotonWrangler · Sep 21, 2007

doc_felixander said:
Sodium persulfate is quite common here. It's not really 'green' (you aren't supposed to pour it down the sink) but it works great at lower temps (40-50° optimum) and gives much better results (less underetching). Ammonium persulfate should work, too.

I've only used ferric chloride and I wound up giving up on doing my own boards because of the underetching problem. I might try a run using sodium persulfate someday.
:thanks:

yuandrew · Sep 21, 2007

I have heard of the Muratic Acid and Hydrogen Peroxide. I can get Muratic acid at lowes, but only in 2 gal quantities. I would prefer something a little less.

There's a member on HIDplanet (an automotive lighting forum I also visit) who uses a mixture like that which he called "Paranha Etch" The mixture called for a 1:2 ratio of concentrated sulfuric acid and hydrogen peroxide (1 Part Acid to 2 Parts Hydrogen Peroxide) . However, this is extremely corrosive and powerful stuff; you will need certain containers for mixing, use, and storage and you want to do it outside or in a well ventilated area as it produces nasty fumes when used. It needs special disposal as well, do not put down drain.

(I added a picture of his workbench with the stuff visible)

erckgillis · Sep 22, 2007

Yes, EVERYONE still use FeCl3...

You'll LOVE this site...suppliers online, retail mail & Brick & morter all by local Country and State!

http://www.mgchemicals.com/products/415.html

best alternates are

Sodium Persulphate Ammonium Persulphate

Based on your copper thickness (mil) and makeup of substrate (fiber) or resin I'd go with:

Home Depot or Lowes and try these (no order) or by price.
Heavy Contractor Concrete Etch-Mix of Phosphorc Acid / Nitric Acid (??%)

Leslies Pool Supply / Spa Supply - Muriatic Acid (HCl ~35%)

Auto Zone/ NAPA - Battery Acid ( H2SO4) 100% try 3:1

These'll eat a copper pipe in half..try a penny and time the amount it takes to 'etch' the smallest lines off Abe's hair or back of coin on the details...

good luck!

E :sssh:

Alternative PCB Etchtants

kf4zht

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DonShock

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doc_felixander

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Steve K

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robk

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kf4zht

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PhotonWrangler

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yuandrew

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erckgillis

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