Trouble etching steel enclosures….black steel?

[wildebelor]

I have some "black steel" enclosures from the US and have been having a hard time getting ferric to etch it deep!
Is there a particular amount of time I should be waiting as I feel It's shouldn't take more than 20 minutes to get a really deep etch and it's taking 20+ minutes to get a very faint etch.
Is this due to the fact that steel, or whatever this enclosure is made of, is more dense and therefore requires MORE heat, MORE time and MORE agitation? 



That is painted and sanded back - not happy at all with the results!

[duck_arse]

I dunno about the steel, but I can tell you that the correct amount of agitation with ferric is that amount that shifts the red-brown gunk that appears on the bare metal. the gunk blocks the etchant from the metal, so nothing will happen till it is shifted. you can use a paintbrush to brush it away.

[wildebelor]

Yeah I've been using a paint brush on it to agitate, however, with a regular hammond enclosure the reaction is quite obvious.
With these, there is barely a reaction!
I'm hoping glops will chime in as he as used the same enclosures.

[Mustachio]

I'd suggest stronger acid solution and more heat. It doesn't look very bad but I understand wanting a deeper etch . I had a problem getting a deep etch as well in steel but the ferric I used was old re-used ferric from radio shack which is sorta weak to start with.

NaoH from what I understand won't etch steel just FYI.

If your mixing  your own ferric maybe make it a lil stronger and use a heat gun (carefully not for to long of periods) on low to keep the acid bath pretty warm. For all etching it seems faster aggressive etching gives better results but its a fine line between that speed and undercutting the mask .

So for each different type of material your etching and the strength of the etchant you will probably have to finesse to get it right. Aluminum is much softer then steel, And steel is a ferrous metal where aluminum is not I'd imagine there's some science there some where that would tell us why one etches different. I don't know the exact science though heh.

Good luck man , the Big Riff still looks cool IMO  

[wildebelor]

I'm giving it another crack and going to try heating it with a gun this time!
If it doesn't work well, lasers on these bad boys!

[wildebelor]

NO LUCK! THIS BLOWS!

I used fresh FC and attempted heat.  Maybe I'll try caustic soda?

[Jdansti]

> So for each different type of material your etching and the strength of the etchant you will probably have to finesse to get it right. Aluminum is much softer then steel, And steel is a ferrous metal where aluminum is not I'd imagine there's some science there some where that would tell us why one etches different. I don't know the exact science though heh.

I think aluminum and copper are more easily etched than steel (iron) because those metals replace the iron in ferric chloride. You end up with aluminum chloride (or copper chloride (cupric or cuprous chloride?)) and iron oxide (rust). However, steel is predominantly iron and ferric chloride is an iron salt, so there's already an abundance of iron and nothing to exchange it with. You might still get iron oxide to a small degree, which explains why it will etch a little.

Traditionally, nitric acid (HNO₃has been used to etch iron, but that stuff is very nasty. I've done a lot of work with it when I digested samples for metals analysis. To be safe, your want to work with it under a laboratory fume hood. It's not  DIY friendly.

Caustic soda is NaOH, and as Jim pointed out, doesn't work on iron.

[wildebelor]

What would you suggest etching it with?
That won't kill me.... haha

[Jdansti]

I don't know if I believe this, but it wouldn't hurt to try. I read on a knife making forum that diluting the standard concentration of ferric chloride helps it etch iron better. The reasoning is that when ferric chloride is dissolved in water, it forms an acid. If you don't have enough water available, you have a weaker acid. They recommend using 1 part ferric chloride from a purchased liquid solution (or the same concentration if homemade) to 9 parts distilled water. Soak the box for 20 min. at room temp, remove, rinse with water and scrub with Barkeepers Friend cleanser and a toothbrush, rinse and then put it back in the etchant for another 20 min. Keep repeating until it looks right.

If you don't have Barkeepers Friend, I'd recommend scrubbing with toothpaste. Just make sure it's clean before you put it back in the etchant. It's the safest thing I've come across. The next step would be to use dilute muriatic acid, which would greatly increase the health risks.

[wildebelor]

Man, I'm kind of at my wits end with it.  Just got a message from Richard/Glops saying that these enclosures etch very poorly and he uses ferric.
I'm thinking I'll just attempt another with this watered down ferric, but I feel like the results will be negligible.

[psychedelicfish]

Man, I'm kind of at my wits end with it.  Just got a message from Richard/Glops saying that these enclosures etch very poorly and he uses ferric.
I'm thinking I'll just attempt another with this watered down ferric, but I feel like the results will be negligible.

The reason Ferric Chloride works to etch steel is that when dissolved in water, the Fe³⁺ ions and the 3Cl^- ions float apart. The Fe3+ ions will react with some of the water, forming Fe(OH)₃, while the Cl^- ions react with some of the hydrogen, forming HCl, or Hydrochloric acid. the Hydrochloric acid will dissolve the iron in the steel, but at the concentrations of HCl you'll get from diluting FeCL, it will take a long time.

My suggestion is to buy some acid. The particular acid used shouldn't matter, but I'd use HCl because it's commonly sold in hardware shops as Muriatic acid, and will probably be more concentrated than that from diluting FeCl.

NaOH won't work on iron or copper(I think) because Fe(OH)₃ is insoluble, as is Cu(OH)₂. The reason it dissolves aluminium is that while the NaOH does initially react with the Al³⁺ to form Al(OH)₃, with excess OH^- the Al(OH)₃ forms the aluminate complex ion, [Al(OH)₄]^-, which is soluble.

[wildebelor]

now THAT is an answer!
I'm going to go buy some acid today and see how it goes!

[Jdansti]

Just in case you've never used muriatic acid (hydrochloride acid/HCl) a few words on safety. Unless you have a fume hood, use it outdoors in a well ventilated area. Wear eye protection, preferably goggles, and wear latex or nitrile gloves. It might not be a bad idea to have a cup of baking soda/water solution nearby in case you get some HCl on you. A micro-drop on your arm will be very obvious!  Use the baking soda solution to help you stop crying like a little girl.

If you decide to dilute HCl or any other acid, always add the acid to water and not the other way around. Combining acid and water is exothermic, and water will act as a heat sink as you add acid to it. Adding water to acid can cause it to rapidly boil and potentially splash you.

I don't know if it's necessary, but it wouldn't hurt to use a baking soda solution to quench the etching process when you're done.

Good luck and be safe!

[The Tone God]

I do know that ferric will work on steel but it takes awhile. I know some guys that use ferric to dissolve steel balls that are pressed in but they leave it over night so I would suspect that ferric does not react very fast. Same with stainless steel etching with ferric, its has to sit for awhile and lots of agitation.

I know some guys who work with damascus stainless steel (which is two types of steel mixed so it has a grain to it) and to bring out the grain they tried a couple of different things. They did try ferric but they found it slow, etched both metals so the contrast was poor, and the finish was very pitted. They had used muriatic acid soaking for 15-45 minutes but they wanted more contrast. They now use sulphuric acid in the typical battery acid concentration (33% ?) just for a minute then immediately neutralize with a baking soda solution. Maybe that is a bit extreme for what you want.

As always be careful with this stuff.

Andrew

[duck_arse]

I've done a lot of work with it when I digested samples for metals analysis.

geeze, that sounds like a tough job.

I'm going to go buy some acid today and see how it goes!

don't let the polis hear/see you saying that.

[Jdansti]

I've done a lot of work with it when I digested samples for metals analysis.

geeze, that sounds like a tough job.

In beakers, not my stomach.

[wildebelor]

Really interesting how much tech / chemistry knowledge there is floating through this forum! 

I didn't get a chance to buy any acid, I wish there was a safer way to do this!

[Jdansti]

There is a safer way, but it might prove to be more difficult.

[Tony Forestiere]

That is UNWORLDLY beautiful work.

[wildebelor]

 

That is just TOO far hahahaha
Really beautiful work.
Hand craft is the best.