Etching enclosures with FeCl3, a few questions

[Vallhagen]

Hi folks.

I have done a few (two, to be specific) fairly successful etches on aluminum enclosures. The latest one here: http://www.madbeanpedals.com/forum/index.php?topic=10407.0. More often than twice though, i have failed in my tries to etch them.

My problem has been that the etches dont go enough deep. I guess it depends on the etchant i have used so far, NaOH, commonly known as "Kaustiksoda (Swedish Word. Caustic Soda in English?)". It works, but the effect is weak. I've had enclosures in warm etching baths for 20 minutes, and the patterns goes viewable, but are barely so Deep i can sense them with fingertips.

Anyway, it's time for upgrade and more trial and error! So i just bought me some 125g of FeCl3 (which i guess is what most of you guys use for etching?). The bottle texttag says that it shall dissolve in 0.25-0.5 litres of water to make a good enough solution.

My questions:
How much is needed to prepare for one enclosure? Or do you prepare all of it and save in a bigger bottle?

is the etchant reusable after one enclosure? if so, i'd appreciate some kind of rule by thumb (as in "say 4 boxes need 3dl of etchant...")

How much time is needed to etch a box? I know it depends on font/pattern width etc, but ... Another rule by thumb? If i remember correct, Slade (at DIYSTB) recommended 4-8 minutes in his tutorial. Sounds sane?

Cheers

[pryde]

I don't re-use my FC after an aluminum etch but I also don't use very much of it per-etch either.

Also, I don't dilute it-just take it straight up 

What I do is put a puddle of FC about the size of the box on a flat plastic plate. I then tape toothpicks to each corner of the enclosure where they stick up about 2-3mm. When you lay the enclosure face-down in the etchant puddle it will stand-off a bit because of the toothpicks BUT etchant should still be contacting the surface of the faceplate. Then move it around gently to agitate the solution under the box.

Time depends on how much area you are etching, if it is primarily just text and lines then 6-8 minutes should be plenty. If you are etching away large areas then up to 15 minutes may be needed (in my experience) but then you risk over-etching the small text areas, etc.

ASLO: Have a plate of water right next to the etchant plate if the box starts overheating then give it a dip!

[rullywowr]

You may want to try using a little heat under the etching tray to accelerate the process.  You could have a slightly larger pan with hot water that the etching container "floats" in.

While FeCl3 works, I would suggest you try Hydrogen Peroxide (H2O2) and Muriatic Acid (H2sO4).  You can get H2O2 at any drugstore and the Muriatic Acid is usually sold in Hardware Stores for cleaning concrete or even pool stores.  A mixture of 1 part acid to 2 parts H2O2 usually works good for me.  Again, a little heat in the form of a hot water bath under the etching container works well here to speed things up.

The benefits of H2O2 and H2So4 are pretty good:
- Inexpensive and easy to find materials
- You can actually see through the mixture while it is etching to know when its time to stope
- A little less dangerous than used FeCl3 and easier to dispose of.

[Vallhagen]

I read your hints guys. Thanx.

When you talk about "hot", how hot is that in terms of degrees? The bottle recommends 20-40 Celsius.

... and yea, maybe i will run on to other Chemistry (H2O2 + H2SO4) later on, now i go with FeCL for the first time though:)

Cheers!

[pryde]

I have done all my etches at room temperature (~70-80F) with FC without any issues. Should be fine with some occasional agitation during the etch

[TwistdDeth]

I have been using Muriatic Acid and peroxide in a small bowl only applying acid to the areas favored to be etched to reduce over etching small text. This, to me, adds a bit of control to the etch process. See my R2G2 build for an example of detail.

[timbo_93631]

I have been using Muriatic Acid and peroxide in a small bowl only applying acid to the areas favored to be etched to reduce over etching small text. This, to me, adds a bit of control to the etch process. See my R2G2 build for an example of detail.

I use the same, though it has been used to dissolve copper from PCB's first so it became cupric chloride.

[jimilee]

This while process is a bit scary to me, that's why I use enviro instead. It is intriguing though.

[Vallhagen]

I have been using Muriatic Acid and peroxide in a small bowl only applying acid to the areas favored to be etched to reduce over etching small text. This, to me, adds a bit of control to the etch process. See my R2G2 build for an example of detail.

Yea, i have noticed that darth vader friendly etch earlier . Great job.

I gotta ask though, how do you mean by "only applying on ... [specific] areas"? I mean, the box is a flat Surface, its hard to just dip a corner etc... Or do you mean that you cover the areas that you dont want to etch with tape or something?  Sorry if the question sounds stupid, but i dont really get it

***

And thanx all for great hints and replies. I had plans to do some etching right when i started this thread, then something came inbetween... But ill be back with result, for sure:)

Cheers

[Gledison]

Hey Vallhagen, im not an etch expert, but a chemist
I think u are already doing the right things. In order to get deeper etching, try to "wash" the parts you are etching with the Ferric chloride. you need to keep "fresh" oxidizing agent in contact with the desired etching parts. IF you are etching just little parts, you can re-use it several times without problem>of course after around 2o times, might not work anymore and you need a fresh one!
ive seen somewhere a guy brushing the etching area with a little piece of a sponge. PLEASE USE GLOVES!!!
it helps to remove the oxidized parts and bring more ferric chloride in contact with the aluminium...
good luck!

[Clayford]

I got a rather nice sized bottle of Ferric Chloride from Amazon and am looking at this guide on doing an etch. Seems to be rather comprehensive and his etches are always amazing.

[Clayford]

double post deleted.

[rosettastoned]

in Chile FeCl3 this is not an expensive product, you can get a 500CC. bottle for 4 dollars and it last a lot. I usually use this method to my builds ( reverse extchin') and just need a sharp knife to do the job.

[hammerheadmusicman]

^Those reverse Etches are SLICK!

George

[m-Kresol]

Ancient thread revival!
I have some questions about etching enclosures since I seem to fail at it. I get results, but they are way off of what I want and what some of you (Cody and Graham ) achieve. I'm supposed to be an expert on a topic like this, but I keep having the same problem, so here it goes:

I always have the etchant eat through my mask at some point. I tried photoresist at first and I thought it was because of the uneven coats you get with the rattle can application I have. So I switched to toner transfer. I tried three different papers, two of them worked fine. The inkjet photo paper was a nightmare as it glued itself to the enclosure at random and was a pain to get off due to melted plastic coatings.
Once I finally had the perfect toner transfer, I etched with NaOH as per grahams tutorial since it is the cheaper chemical to "borrow" from the lab. The result was rather poor having lots of fine details etched away. To be fair, I didn't pay to much attention to it, as I just did it on the side while working. I recently did an etch again with FeCl3 as per Cody's tutorial and it worked well except for the problem that the etchant ate through the mask at some point making the enclosure looking not half as good.

*What am I doing wrong? Is my solution too concentrated? my pH too low/high (I added a little hydrochloric acid to regenerate the FeCl3 solution so it is rather acidic)?
*I guess, so long as the toner transfers completely, I got a good combination of printer and paper, right? or is there a specific toner?
*Am I etching too long? It takes me about 15 - 20 min I guess. I tend to lightly scrub off the rusty looking gunk to see the depth of the etch. Could it be that I remove part of the toner there? How deep are your etches? I tend to think that I etch too long and deeper than necessary.

I appreciate any input you could throw my way. I put quite some time into this, but couldn't get it solved. Trial and error would probably lead to a working procedure, but as the semester started again and my boss is pushing me lately, I don't have the time for that atm.
Thanks for all your wonderful tutorials guys and thanks for any comments!
Cheers,
Felix

P.S.: this is haunting me so badly, that I even dreamt about Cody. In a non-romantical-he's-showing-me-how-to-etch way This stuff is starting to wreck my brain