Local sources for Ferric Chloride?

spinnaker

Joined Oct 29, 2009
7,835
What are some local sources for for Ferric Chloride? I have been reading the Shack does not carry it but it shows up on their website as PCB etchant. Is this actually Ferric Chloride or some other kind of etchant?

Has anyone used this stuff from the Shack? Seems like a pretty decent price considering you do not have to pay for shipping.

I have read that it also can be obtained from art supply places?

SgtWookie

Joined Jul 17, 2007
22,210
I actually still have an old RS PCB kit that has a full bottle of their etchant in it.
The bottle cautions that it contains Ferric Chloride.

Note that on the Radio Shack site, it states:
AVAILABILITY: IN-STORE ONLY Available at most stores, find it near you
I don't know where their most stores are located, as none of my local RS stores carry it anymore. It's due to the stupid "hazmat" laws nowadays.

I've been using 2/3 parts hydrogen peroxide (drugstores, grocery stores) to 1/3 part muriatic acid (swimming pool supply stores)

The muriatic acid is nasty stuff. Use it only in a well-ventilated area. Wear rubber gloves and protective clothing/eyewear; don't splash it on you. Keep a bucket or two of water handy in case you goof up. If you spill it on concrete, the concrete will become permanently etched, as my garage floor will attest to.

Add the muriatic acid to the hydrogen peroxide. Don't do it the other way around.

I've found that the black plastic trays that pre-packaged microwaveable food comes in works well with this etchant. Don't use anything that has nylon or dacron in it, as the muriatic acid/hydrogen peroxide combo will make it soften, and it will ruin your board (ask me how I know this. )

I use a soft paper towel or a rag to gently rub over the board while it's etching; this speeds up the process quite a bit. As soon as the copper is etched away, dunk the board in clean fresh water to dilute the etchant and stop the etching process. Rinse it well.

Etching should be done in just a few minutes.

If you decide to save the partially used etchant, you might try it - but be warned, it will continue to heat after etching as the dissolved copper is consumed; and if enclosed in an air-tight container the, container will become pressurized.

I tried saving some of this etchant in an empty hydrogen peroxide bottle; when I went back to look at it the next day, the bottle was twice it's original size and much more round than it originally was. I don't know how I escaped disaster on that one.

If the mixture is diluted enough, it's pretty harmless - won't even etch your boards anymore. When you're done etching boards with it, mix it with a few gallons of water in the toilet.

franklinmknight

Joined Jan 3, 2010
13
Yes, it is ferric chloride. Radioshack just doesn't use the chemical name. It works quite well also, better than the hydrochloric acid/peroxide solution because it doesn't erode the masked traces as violently. You've probably read that the HCl/H2O2 solution is faster, IMO it isn't worth risking small traces for the slight increase in speed.

I hope this answers you're question well enough. Good luck with etching your own PCBs also; I had a hell of a time doing it myself, ruined several boards.

Edit: Sgt. Wookie beat me to the punch.

spinnaker

Joined Oct 29, 2009
7,835
The one post I saw (on another forum) said they went into the Shack and asked for Ferric Chloride. They said they did not have it. He then read a post that the Shack was calling it Etching Solution. So he wasn't back and asked for that and they had it.

He went back to the store a couple of days later and asked for etching solution and they had it.

Apparently you need to be specific. That is the problem, they carry little anymore and what they do carry, they have no idea what it is.

I might give it a try tomorrow.

Has anyone tried art supply places? I guess they also us it to etch metals for artwork.

Two problems with muriatic and peroxide .

I really don't have a place to use it other that outside and I think I will be snowed in till June. I have a basement but it is certainly not well ventilated. BTW you can get it at Home Depot. At least I think is where I got some.

The other problem is mixing it. I think for a newbie, ferric chloride is probably a bit more full proof.

spinnaker

Joined Oct 29, 2009
7,835
Yes, I would try the ferric chloride first. Although you still want some ventilation, FeCl isn't nearly as volatile as the HCl H2O2 mix. At the Radioshack here I think I only payed \$10 for a big bottle of the FeCl.
So some of the stores do have it.

Would I be fine in my basement or should I still use the stuff outside? Not sure where right now.

What about a bathroom with a ventilator? I'm going to have to find a nice big large tray to work over to catch an accidental spills.

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Wendy

Joined Mar 24, 2008
22,138
Ferric Cloride will rust and ruin any metal in the vicinity if stored casually. My solution is to role a single sheet of paper towel tightly, then wrap it around the lid and tape it securely in place. The paper towel will absorb the fumes and prevent it from finding other things to eat. In bottles I have stored for over 10 years the paper towel was incredibly brittle, but still doing its job.

BMorse

Joined Sep 26, 2009
2,675
apparently this stuff is getting harder to come by in liquid form because of hazmat laws in shipping, you would be better off buying the powdered form of FC and mixing it yourself, I have done this before and it works quite well..... http://shop.vetcosurplus.com/catalog/product_info.php?products_id=939

make sure you mix it in a glass jar though, not plastic, since when mixed it creates a lot of heat!!

jpanhalt

Joined Jan 18, 2008
9,057
I've seen better prices on ebay. I can also mention that if you get the hexahydrate, instead of the anhydrous form, it does not evolve heat on mixing with water.

Since the formula weight of the hexahydrate is greater, if you are using a recipe, you should use 5 units of hexahydrate for every 3 units of anhydrous form that is called for to be identical.

The concentration is not critical, and you may not need to make that adjustment.

John

spinnaker

Joined Oct 29, 2009
7,835
I scored 2 16oz bottles from the Shack.

I was told as long as it is available as an in store item, they will order it for you even if they don't regularly stock it.

You need to ask for it by "PCB Ecthant". They had no idea what the stiff was.

Also you can ask that they search nearby stores. This is how I found mine.

jpanhalt

Joined Jan 18, 2008
9,057
Ah, whatever happened to "you have questions, we have answers?"

Good luck. John

retched

Joined Dec 5, 2009
5,208
Yeah, to save on printing costs, they shortened their motto to:

You'll have questions.

spinnaker

Joined Oct 29, 2009
7,835
Yeah, to save on printing costs, they shortened their motto to:

You'll have questions.
Actually their new motto is "You guys better have the answers because we don't know nuttin about no electronics stuff".

BMorse

Joined Sep 26, 2009
2,675
Ah, whatever happened to "you have questions, we have answers?"

Good luck. John

It is more like "You have questions, we have blank stares....."

I was in there the other day picking up some monolithic caps for a project I am working on, one of the sales people come up to me and asked if there was something he could help me find, so I told him that I was looking for some stereo caps and all I could find are mono's, so he went to the computer to look them up after a few minutes of looking through their online catalog he came back to tell me that he was sorry and they do not seem to carry any stereo caps.....