Fun with photo etching

[Steamer Al]

Anyone who doesn't want to play with really nasty chemicals I would recommend these guys. http://ppdltd.com/

I had looked into doing photo etching at home years ago and concerned Ferric Chloride wasn't something I wanted around the house or to deal with. I get great service from ppd, at a reasonable cost, and they're used to our market.

About the only nice thing with doing your etching at home is being able to etch out your own machined part as was posted here but I am not sure dealing with hazardous chemicals you can't just throw away is worth it?

I think I would be more inclined to get my CNC milling machine up and running and engrave before I do home etching but maybe others don't find the stuff to be so bad to deal with?

What are the fumes like will they damage the tools in your shop the way working with acid solder flux can?

Those who do etch at home what are your expectations with Ferric Chloride and what do you do with the spent waste?

Apm, I certainly would not do the etching indoors. I did it outside and placed the container of acid in a tray of warm water to keep the temperature up being winter time, probably not necessary in summer. I also wore a organic vapour repirator when using it just to be extra safe.

I haven't used ferric chloride, but muriatic acid is used for cleaning conctrete and neutralized in the process, so I deem that a safe method of disposal. I do it away from the house as an abundance of caution, I have an old concrete slab foundation on my property where I neutralize it. Instructions for disposing of muriatic acid state that neutralized acid can even be disposed of down the drain. The hydrogen peroxide used is the very low concentration medical stuff, which poses no environmental hazard itsself.

Alex

[Bill Shields]

I could tell a story about an two guys using an aluminum boat in a ferric chloride pond...but it would be a very short story.

And a very hot one ( temp wise ) too !

actually not all that hot since there was several million gallons of FeCl in the pond to carry away the heat.

although they had been warned against it, the contractors (in the boat) figured that they would use the cheapie aluminum boat once and throw it away)....a fiberglass boat was too expensive.

They were correct on half of the equation -> they DID use it only once -> but there was nothing left to throw away...

got their belt buckles, trouser zippers, eyelets and steel toes in their safety shoes in the process => since they had to walk to shore where the guys with the water hoses were waiting.

[Rick]

Alex,
Looks good
I have done some photo etching. I used the spray on resist. Also had edges that were not sharp and clean.
Found out the when I printed my design on transparent film the thickness of the film when developing let the light bleed under the art work. I then printed the artwork reversed so that the printed side of the transparency was against the resist. This brought about very good results.

That looks great Rick! Ill have to look into the spray on resist. Any idea how deep you got? What kind of acid did you use?

Cheers

Alex

Alex,
I got about .010 to .012 deep which was deep enough for what I wanted. What I used was labeled as "PC Board Etching Solution" it contained Ferric Chloride and HCL acid ( no indication to ratio of each)

[Bill Shields]

Yes, it's is an acid -> however if you dilute it with enough water and / or baking soda....

Where I worked back in the 70's -> we used to sell our by-product FeCl to drinking water treatment plants.

they use it to cause entrained solids to fall out of solution in settling tanks. (flocculant?).

might be good for cleaning up the murky water in fish tanks....

[jcfx]

actually not all that hot since there was several million gallons of FeCl in the pond to carry away the heat.

although they had been warned against it, the contractors (in the boat) figured that they would use the cheapie aluminum boat once and throw it away)....a fiberglass boat was too expensive.

They were correct on half of the equation -> they DID use it only once -> but there was nothing left to throw away...

got their belt buckles, trouser zippers, eyelets and steel toes in their safety shoes in the process => since they had to walk to shore where the guys with the water hoses were waiting.

Based on my experirnce it gets pretty darn hot, my first attempt at etching aluminum I left
the plate in the ferric chloride and let it bubble away ( watching of course ) I started to see the resist
floating in the FeCl3 when I reached ( gloved of course ) in to take the plate out to inspect it was hot
enough that I couldn't hold it for very long.

What are the fumes like will they damage the tools in your shop the way working with acid solder flux can?

Those who do etch at home what are your expectations with Ferric Chloride and what do you do with the spent waste?

Etching brass the fumes are negligible, since it's a slow reaction, I do it in front of an exhaust fan,
besides if you're not etching in an industrial scale, small name plates etc. and at the most you're
going to use half a cup to cup of FeCl3 solution. It's far different than using acid based fluxes.

FeCl has it's pluses, it's reasonably fast you can get really nicely etched lines if the photoresist is
applied well. the FeCl3 solution is readily available from electronics hobbyists sites, and is reuseable till it's spent.
I keep separate pint bottles for brass and for aluminum.

This site has a good FAQ on disposal of spent FeCL3 -
https://www.mgchemicals.com/products/ci ... e-etching/

There is an alternate etching method that is salt water based electro etching that I haven't delved too deeply in
it takes a lot longer, only byproduct is hydrogen and copper chloride.