Enclosure Etching with lots of pitting

[kraigen]

Hello, I've recently started to etch enclosures and I haven't had great results. There is a lot of pitting after using the etchant. The Ferric Chloride just went through the toner and caused a lot of pitting. Should I just try going over the toner with sharpie as a safety measure? I printed the design in high quality, FYI.

[slashandburn]

 Sharpies could help. I found nail polish works better over larger areas. For even larger areas to be masked off I've found parcel tape works wonders, though it's a pain to clean off after the job is done.

Not meaning to sound discouraging but there's quite a lot can go wrong. Ferric chloride eats the aluminium quite aggressively, pitting could be caused by leaving it in there too long, not just poor toner transfer. Concentration of the ferric (I dilute it a little to etch Aluminium, and dilute it a lot for copper boards, but that could be false economy and just what seems to work for me after a lot of trial and error) and however many times it's been reused play a role.

Practice man. I've messed up countless boxes. I'm sure most etchers here would say the same.

[kraigen]

I guess so. I've never messed a copper board, though, so it's a bit strange for me. But I'll keep at it. Thanks!

[slashandburn]

Sorry, I should've elaborated. I dilute the ferric more for etching copper because for some reason it seems to etch faster. The stronger solution doesn't mess up the boards, it just seems to work slower.

I can't explain it, it seems to fly in the face of logic. Maybe it's all in my imagination. Anyway, not really relevant to your problem with pitting. I guess I was just trying to suggest experimenting with different strengths of ferric chloride.

Edit: you could also try lye/sodium hydroxide solution for your enclosures. It's less aggressive, though the downside is it's much slower. It'll burn through your flesh quite aggressively though (I learned the hard way) so be careful with it.

[DK1]

Sharpie won't work as an etch resist with lye solution. Also, lye can be quite aggressive, depending on the concentration you use. Vinyl is a decent resist for it, so pvc glue or liquid tape work OK, but they can have trouble with adhesion at the edges on bare aluminum and if you don't get all the paper off the toner, it'll release under the overlaps.  Lye will eventually eat through toner masking also. I've found it goes through the mask too quick to get a deep etch in the metal. Likely depends on mixture strength.

Lately, I've found light mixtures of muriatic acid and hydrogen peroxide work pretty well. Quicker than lye, and gets deeper for me. Gives a better tradeoff on getting deep in the aluminum before eating the toner. Also works really well for me on pcbs. However, if you let it go too long, it can give really deep pits. So, you've got to pull it out right on time.

I'm going to be trying electro etching soon. I've never tried ferric chloride, but I have some I need to test with. Good luck.

[kraigen]

Thank you all for your kind replies, I think I will try Ferric once more, but now I'll use nail polish over most of the toner and see what kind of results I get.

[slashandburn]

There are some good guides here, I'll see if J can find the one I used when starting out and I'll link it later.

The enclosure will heat up as your etching, don't let it get too hot, take it out periodically and rinse it down with cold water and wipe it down gently to check the toner mask is still intact. (If you're not already doing that)

Good luck. And don't be shy about posting pictures of your results. I'll bet even the pro's here still occasionally f*ck up when it comes to etching boxes. And I do like a bet!

[xorophone]

I asked the same question here pretty recently and I got a lot of great tips in the replies. It's still really hard for me to get a good result, but when I finally do, it's all worth it. Don't give up!

Here's a link to the thread: http://www.diystompboxes.com/smfforum/index.php?topic=117009

Good luck!

Edit: Another thing that might help is to make sure the enclosure is very well sanded with a very smooth sand paper, because as you can see on the picture in my thread, the unintentional "grooves" around my design are mostly lines going in the direction I sanded the enclosure.