Etching

Hum - there is a certain amount of free HCL in Ferric chloride. That might be the active agent - making more Ferric Chloride and hydrogen.

Likewise HCL would do the same. Using HCL for taking scale and rust off it tends to turn metal a gray.

Martin

Mart> Joseph Gwinn fired this volley in

Well ... the FeCL (Ferric Chloride) is less hazardous, but it is a nasty yellow stain on anything that it gets on.

Don't use *either* inside your shop. Both produce vapors which will rust things like mad (which is what you are doing through the beeswax resist anyway. :-)

Enjoy, DoN.

According to Ed Huntress :

Well ... I've used both Nitric and FeCl for etching copper printed circuit boards, and the nitric was far more vigorous -- easy to overdo the task.

No Idea how either work on ferrous metals, however.

Enjoy, DoN.

Wax, beeswax would make a good resist. Since he's only 11, I'd suggest HCl, (muriatic acid). It will work, (a bit slower), and is a bit safer than sulfuric or nitric acids.

I've used nitric and ferric chloride for etching copper printmaking plates. The main difference is that the nitric dissolves the metal and it's mostly gone, while the ferric leaves residue in the bite. For that reason, it's helpful to etch upside down in ferric so the residue falls away. (Prop up non-etching areas of the plate on some small plastic blocks; you might also want to rinse your plate and brush off residue from time to time.)

For copper, the best etchant is dutch mordant (hydrochloric acid + potassium chlorate). Unfortunately, it's both difficult to obtain and rather dangerous. The ferric is the least dangerous of the three. The ferric also has a rougher bite than the nitric. The results can also vary quite a bit depending on the acid strength, both the original dilution amount, and the amount of etching time you've used it for.

Also, regarding the resist, check out some printmaking suppliers. The "hard ground" they sell is a brush-on resist that's thin and easy to draw on, it's also easy to remove with solvent. Try Graphic Chemical and Ink in Chicago. The hard ground will be easier to use than beeswax, particularly if your design has any fine detail.

Thanks, Jedd (and Don). Have either of you ever tried it on steel?

I've used it on copper circuit boards but this is the only place I've heard of it being used for steel. I've done some etching in steel with nitric acid, a couple of decades ago, and I learned that you have to use several bites to prevent severe undercutting.

I'm curious both about the speed of ferric chloride in steel, and the way it cuts -- undercutting or not.

-- Ed Huntress

In the 70's I knew a PCB etching house owner. New a better one later in life... This guy was on top of production - did great stuff and was being pushed for more and faster. He converted his automatic spray machine to something like hydrogen cyanide or the like. He found out one day he had a leak. It misted him as he walked by and had to have his sinuses rebuilt from other parts on his body. He looked like a mess for some time due to the operations.

It worked very well and for a while they just built a plexi shield all around it. Collins Radio was a big contract and IIRC, an audit by them (visit) identified their issue - to much demanding when speed wasn't needed. They paid to get the cyanide system out of there and back to a normal spray. With that, he upgraded to another line and just ran two.

Mart> >

Join this forum, it's free. Sorry I didn't think to mention it sooner.

I think shipping any chemical across a border , post 9-11 would be a nightmare . Now Sunday , holiday weekend and no acid . Nor a line on where to get any . Sadly . Ken Cutt

I had always intended on this being an outside operation . Ken Cutt

The big plus is I can get my hands on muriatic any day of the week . Thanks Ken Cutt

I will check it out . Also give my nephew a gentle shove in that direction . Not a knife maker myself , just like most of the posters here I work with metal so anything metal relatives need my phone rings . I will admit that I am enjoying this project as it has made me learn new skills . Always a big plus in my book . Ken Cutt

Unknown fired this volley in news: snipped-for-privacy@4ax.com:

Ahh... I suppose it's actually tin and fluorine...

You post too slowly. I already corrected myself.

LLoyd

For your information it is more correctly referred to as iron(III) chloride which consists of trivalent iron ions and chloride ions not iron and chlorine.

Perhaps I was too subtle for someone pontificating on a subject which they knew very little and what they thought they knew was incorrect.