What's the best etchant for etching aluminum enclosures?

[greaser_au]

- 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.

yes it works! Best for big chunky tracks.   Year 10 Applied Electricity project was a power supply with an M-2156 transformer, and you could have the basic one with a basic float battery charger or the advanced one with the charger and the CB power supply. I was allowed to design my own- mine had a variable power supply based on an LM317 with a booster transistor. I made my board with bituminous paint. it looked ratsh*t

david

[duck_arse]

we didn't have electricity in year ten. r.g. hadn't invented it yet. and they let you play wit the mains??

[greaser_au]

and they let you play wit the mains??

interestingly, yes.  mind you, the teacher (hello Mr Wynne, wherever you are) made very careful checks.

my kids went to the same school recently, and they're not even allowed to use the magna-bend (electromagnetic sheet metal brake)

david

[esauvisky]

Hey guys, it's been a couple of months and I've made lots of improvements. Let me show you so others can help themselves.

I've made a device like CodeMonk's one (thanks pal). I call it The Bubbler. This is actually what really made a difference.
It's made from two icecreams bowls stack together and glued with epoxy (must be epoxy for an air tight seal!).
The upper bowl has a grid of holes and a hose also glued with epoxy. Remember to sand everything that is going to be glued.
The air comes in from the hose (preferably from an air pump, but I've used my mouth ) and leaves through the holes.

(click pictures for full-res)



These are the results. It's much faster, controlled and flat with the bubbler.
Of course, one box is already painted, but it gives you a good view.
There's still room for improving, you can see that even with the bubbler there are some failures where the etchant went through the PNP.


I hope it helps someone, it took me several trials to get it right

[defaced]

Nice work! What hole diameter and grid spacing are you using on the bubble plate?

[Arcane Analog]

PNP will limit the quality of an etch. I have a few sheets left and I will only use it for PCBs now. Cheap photo papper is far superior.

I am curious as to how long folks are taking to etch their boxes and why the need for the bubbling agitator. In my experience you only need a few minutes maximum for quality etches. Increasing the speed any more will increase amount of ruined etches and/or unwanted exposure to etchant.

[esauvisky]

Nice work! What hole diameter and grid spacing are you using on the bubble plate?

I've made the holes with a small needle, so I can't tell you the exact hole diameter , probably around .5mm. The spacing between them is 1cm (12 rows, 8 columns).
Actually, I didn't pay too much attention to that, do you think it's relevant?
I'll make more bubblers for some friends, as they work greeeeat for PCBs (etchs in 2 minutes), and I'll try out new things, like finding out a way to stop the etchant from going through the holes.
Maybe fiddling with the hole diameter and spacing also improves something.

PNP will limit the quality of an etch. I have a few sheets left and I will only use it for PCBs now. Cheap photo papper is far superior.

Yeah, I know PNP is worse than (some) photo papers, but I'm still looking for a good alternative avaible here (Brazil).

I am curious as to how long folks are taking to etch their boxes and why the need for the bubbling agitator. In my experience you only need a few minutes maximum for quality etches. Increasing the speed any more will increase amount of ruined etches and/or unwanted exposure to etchant.

I've already seen you saying that it's not necessary. However, I've tried etching without the bubbler several times and it doesn't even scratches the surface without at least 30 minutes. Maybe your etchant is stronger or my boxes are harder, I don't know.

[deadastronaut]

Cheap photo paper is far superior.   

Increasing the speed any more will increase amount of ruined etches and/or unwanted exposure to etchant.

yes.

and yes..

the strength of ferric/water/heat   makes quite a difference too imo.

i bought a new batch of ferric, and its the best yet, i used to buy the 'ferric balls'...but i found this guy who sells it as a kind of gritty paste..

a bit like road ice salt...1kg in a solid plastic drum for £11.00. that'll last me a log while...and ive noticed the price of those ferric balls is getting ridiculously high now on ebay.....

and maplins are taking the p... with it for sure....like everything else they sell.

[duck_arse]

and I thought ice-cream containers were only for paint-water and rainwater. nice work, but my sister won't be happy when more containers dissappear.

[tremelo68]

PNP will limit the quality of an etch. I have a few sheets left and I will only use it for PCBs now. Cheap photo papper is far superior.

Hey guys,

I am trying out  etching for the first time and CANNOT get a good transfer from photo paper to the enclosure. My setup is: Brother HL-2040 laser printer, HP Advance Photo paper (it's glossy and what I have on hand).

Whenever I iron it to the enclosure, it does two things I haven't heard about on this forum/thread and on others: the back of the photo paper sticks to the clean sheet of paper I use between the iron and the photo paper (thankful I have that or else my iron would be toast); and the photo paper completely sticks to the enclosure, paper and all. The glossy film does not peel apart. It becomes one big mess and I have to scrape it clean and re-sand the enclosure. I have tried different heat settings, different times, I even tried regular for a simple toner transfer, but no luck. I am trying to follow the Ruz Guitar Gear guide for etching posted elsewhere on this site, but I can't even get to a good transfer yet...

Do any of you have a known working paper to recommend? In the USA. I have a Staples near by and other places as well (Target, craft stores, etc.). Thanks

scott

[DeusM]

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

Holy mother of litle baby jesus! Did you used ferric for that? I was lookin for caustic soda for etchibg since I thoug it was better for etching but now I see that I might try using the ferroc I have. I didn't know you could try shading with etching. Excelent work

[stringsthings]

Those etches are some of the best I've ever seen.  I should get some ferric.

[DeusM]

Those etches are some of the best I've ever seen.  I should get some ferric.

Definitly. It's mindblowing. I have some ferric. The down side is that it looses efectiveness and it's very bad for the enviroment. I'll give it a shot though

[stringsthings]

Yeah.  I like that I can use caustic soda and drop it down the drain.  I'm a poor housekeeper anyways
so having some around is always handy.

I've used ferric in the past with good results.  But geez, it stains everything in it's path.
And, as already posted, it's not real great for the environment.

[amptramp]

There are some people who do electro etching where the object to be etched is connected to a positive DC supply and the negative is taken to a solution that is conductive, like salt water to a cathode made of the same material as the object being etched.  The voltage and concentration of the solution give you some level of control over the speed.  The advantage is that ordinary salt can be used.