What's the best etchant for etching aluminum enclosures?

[esauvisky]

Thanks for the compliment! I won't have all of my pedals for ever! Friends keep requesting I build them stuff! Its a shame that prepping them really isn't one of the jobs that gets faster (per box) if you do multiples. I mean I could populate the board of I'm guessing 8 of the same design pedals in the time it takes me to do 2 of different design. It seems people I know all want vintage rats after they hear mine (and some before!). I wish I made ten in one go rather then one..then another one...then two at once. I could have saved a fair amount of time.

Yeah, I'm also producing pedals for selling, and their absence of scalability (without automation) is a pain in the ass.

What I've suceeded to do is to break production into several steps:
1 - Sand box
2 - Drill lateral holes
3 - Apply PNP
4 - ...
You do one step for all pedals, then the next step and so on. Don't go to the next step if you haven't finished the previous one on all pedals.
This way you gain some time, as you avoid fixed costs of opportunity of switching between production steps.

[esauvisky]

You should add one of these for etching (be it enclosure or PCB):



[...]

Thats INSANE! Really good idea for a more automated version of an etcher, definitely going to work on that.

I just have a question about it: do etchant gets underneath the floor padding? Is there any space between the padding and the bottom of the container?

[CodeMonk]

You should add one of these for etching (be it enclosure or PCB):



[...]

Thats INSANE! Really good idea for a more automated version of an etcher, definitely going to work on that.

I just have a question about it: do etchant gets underneath the floor padding? Is there any space between the padding and the bottom of the container?

The floor (Its a piece of rubber taken from the floor mat from a horse trailer) fits pretty snugly in there.
But I also used hot glue to both seal and to help it stay in place.
There might be a little bit of space between the rubber and the bottom of the container, but its minimal and with the hot glue, no etchant gets down there (Hopefully anyway )

The larger round container was an ice cream container in its former life.
The rectangular etching "tank" used to hold potato salad from Walmart.
I normally only use that round one to put the "tank" in after use when I don't feel like cleaning up at the moment.

When I am etching, I keep the "tank" in a larger rectangular plastic box to contain any spray or whatever that happens as a result of all that bubbling.

[deadastronaut]

I'm no expert at all! I've only etched about 15 boxes so far and the first few were pitted badly. I think it will always be a learning process for me, but that's ok. Agitating the crap out of the box while etching really makes it go fast. The last one I did got so hot I couldn't even touch it and it etched in 5 min. Maybe it got hot from the evilness of........
THIS!!

nice, that came out great...

i would have had to put 3mm leds in the eyes for extra evilness..

[pakrat]

Thanks Rob, JOK3RX said the same thing! I didn't do the leds because her eyes are the scariest part and I didn't want to mess it up. I'm building another though....

@CodeMonk  Even if it ends up getting dirty beyond cleaning, I doubt you will have a shortage of empty ice cream containers 

[duck_arse]

her eyes

. her? geeze.

anyway, I have three things to add to etching discussions:

- bituminous paint. it used to come in a tube with a paint brush, and we were supposed to paint it onto blank pcb as the etch resist. I doubt anyone ever managed a board with this method, but the paint is thick, black, bituminous and etch resistant. I don't know where you would get it these days.

- dalo pens. these are still available here in australian component shops for 10$, I can't say for the rest of the world. a felt (fine) tipped pen with spare tip and thick blue ink. etch resistant. you could draw a decent board with this with a steady hand, just like you foreigners would call a "sharpie". I've never seen them mentioned hereabouts.

- ferric chloride. heated or not (I've never heated it), it - MUST - be agitated for it to work at all, its chemistry says so. bubbles are the quickest and cleanest, epecially in a "bubble tank" for pcbs. not quite as practicable for boxes though.

carry on

[Canucker]

Thanks for the compliment! I won't have all of my pedals for ever! Friends keep requesting I build them stuff! Its a shame that prepping them really isn't one of the jobs that gets faster (per box) if you do multiples. I mean I could populate the board of I'm guessing 8 of the same design pedals in the time it takes me to do 2 of different design. It seems people I know all want vintage rats after they hear mine (and some before!). I wish I made ten in one go rather then one..then another one...then two at once. I could have saved a fair amount of time.

Yeah, I'm also producing pedals for selling, and their absence of scalability (without automation) is a pain in the ass.

What I've suceeded to do is to break production into several steps:
1 - Sand box
2 - Drill lateral holes
3 - Apply PNP
4 - ...
You do one step for all pedals, then the next step and so on. Don't go to the next step if you haven't finished the previous one on all pedals.
This way you gain some time, as you avoid fixed costs of opportunity of switching between production steps.

Good point! I was a little lazy in my thought process on my response. Partly because I'm still in the early stages of having a few projects on the go at once. I did a fair number of things one by one and have never had more then two boxes on hand that needed working on. The next pedal I push on a friend all the money will go to boxes...if I have ten untouched boxes in front of me all at once I will get a proper system going. According to the "15 boxes and your work can look like this" idea of Ms. Scary eyes I'm just 8 boxes away from managing some pretty kick ass graphics! 

[pakrat]

Thanks for the tips duck arse. Try heating the ferric chloride on your next etch and see if it goes any faster for you. And ebay has bituminous paint, which I've never heard of but I might try it.

@Canucker  15 boxes later and I still get occasional pitting, not as bad as I used to. My plan is to be able to etch as clean as deadastronaut or slade. not a pit to be found.

[deadastronaut]

i always heat my diluted but strong ferric, ...makes for a better agressive etch...i have it pretty hot sometimes, and it doesn't melt the toner.....fizzzzzzzzzzzz...

cold etching takes ages...

[Arcane Analog]

Ferric is by far my preference.

If you are going for detail heating the etchant is not a good idea. You want slow controled etching to get the exact detail you want.

If you are looking to have an agressive etch, say for a 'reverse' etch like Linda Blair, heating it will speed up the process but it can also eat the aluminum at a very uneven rate.

[ch1naski]

Try HCL!
15% and take 2 minutes to etch. Very fine lines. And please dont do it with warm water.
Take 50ml water and 50ml 33% HCL.
IMPORTANT: first water and then HCL or the HCL flies into your face. Wear handgloves and glasses!!! And do it outside, do NOT breathe the steam in.
Some pics (all made with HCL)
http://imageshack.us/a/img716/3489/030tvr.jpg
http://imageshack.us/a/img821/1290/bilders2051.jpg
http://imageshack.us/a/img718/4553/bilders2012.jpg
http://imageshack.us/a/img547/2180/022ro.jpg

those are super clean lines. Ok May have to try HCL.

Hydrochloric acid, right?

[pakrat]

Agreed, those are some nice etches.

[Arcane Analog]

I have yet to find anything that can get as clean and detailed - including shading - as poperly prepped boxes and Ferric.

[deadastronaut]

beautiful...nice work man.

[Canucker]

Thanks for the tips duck arse. Try heating the ferric chloride on your next etch and see if it goes any faster for you. And ebay has bituminous paint, which I've never heard of but I might try it.

@Canucker  15 boxes later and I still get occasional pitting, not as bad as I used to. My plan is to be able to etch as clean as deadastronaut or slade. not a pit to be found.

Hey hey hey! I made a plan...don't go messing with it!!! 

[pakrat]

Sorry Canucker......... 

Really Arcane, those are incredible looking! Sigh.....

[samhay]

I gave NaOH a try today. It went straight through the etch-resist (a few layers of permanent marker pen) and I now have a vey smooth box, which is a couple of shades darker than when I started.
I used a nearly-saturated solution, which may have been way too strong. It got quite hot, bubbled quite vigourously and gave off quite a lot of gas, which was probably H2.
Can't say I would recommmend the method for etching, but it might be useful for cleaning the box prior to etching with something else. 

[esauvisky]

I have yet to find anything that can get as clean and detailed - including shading - as poperly prepped boxes and Ferric.
[...]

Arcane, how do you properly preppare your boxes for etching then? Also, how do you do shading?

BTW, your pedals are awesome

[Arcane Analog]

Thanks for the kind words.

Im my opinion, the box prep should remove the top layer of oxidized aluminium to facilitate a good transfer and to ensure (as much as possible) an even etch. Sometimes you can get away with just cleaning the box with acetone or your cleaner of choice. The shading is simply learning when to stop the etching process and that is more of a feel or an art as opposed to something I can give specific directions on. Each box can react differently to the etchant.

[Maik]

Hydrochloric acid, right?

Yes. And have a look every 30 sec, cause it goes realy quick.
And I use this, it´s like pnp but as a spray.
http://imageshack.us/a/img17/526/bilders2009.jpg
Then with transparent film and uv light. This also gives finer lines (for me, I allways had problems with paper)