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finally going to start etching boards

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LAN_403

Forty

Fri Sept 16 2011, 04:36PM

Registered Member #3888 Joined: Sun May 15 2011, 09:50PM
Location: Erie, PA
Posts: 649

I think I'm going to buy copper clad from abcfab on ebay.
should 2oz copper be thick enough for most power applications or should i get higher?
I don't want to end up with blown traces on a zvs flyback driver or a smps.
and is double sided really worth it or does it just get in the way for simple circuits?

I might just pick up this 3lb box to get me started:

any input or suggestions?

dude_500

Fri Sept 16 2011, 04:43PM

Registered Member #2288 Joined: Wed Aug 12 2009, 10:42PM
Location: Cambridge, MA
Posts: 179

Etching is great, I do it for just about every project I do even early prototyping. Haven't even breadboarded a circuit with more than a few chips since I started etching, it's just so quick and easy.

If you want to make double sided boards, you need double sided copper clad. If you don't, it just makes your life harder since you either waste etchant removing it, or must remove it by abrasion or peeling. It's usually good to have a bit of both on hand.

2oz is the typical thickness of the copper clad you will find on ebay, so you may as well go with that. If you want to carry tens of amps through a somewhat small trace, just cover the trace with solder and it will do it no problem. It's good to tin boards with solder anyways, so just add a bit more than you typically would if it's a power trace.

Forty

Fri Sept 16 2011, 05:12PM

Registered Member #3888 Joined: Sun May 15 2011, 09:50PM
Location: Erie, PA
Posts: 649

i picked up a 3lb box of 3oz double sided for $13.25 usd shipped. figured more copper wouldn't hurt.

for etching it i am going to make up my own copper chloride solution using HCl, H2O2, and scrap copper. anyone have experience using this etchant method?
The circuit will probably just be drawn on with a sharpie marker using a stencil.

Conundrum

Fri Sept 16 2011, 10:14PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061

I have some ampersulf here..

Another method is vinegar, peroxide and a very small amount of salt.
This works but not as well as normal etchant.

-A

Turkey9

Sat Sept 17 2011, 02:36AM

Registered Member #1451 Joined: Wed Apr 23 2008, 03:48AM
Location: Boulder, Co
Posts: 661

I've used that method before. Don't try to make copper chloride, just use the HCL H2O2 as it etches extremely fast and is very cheap. The sharpie probably won't stand up to it though, so I would suggest the toner transfer method.

Forty

Sat Sept 17 2011, 04:18AM

Registered Member #3888 Joined: Sun May 15 2011, 09:50PM
Location: Erie, PA
Posts: 649

I'm not worried about etching speed, as i usually have enough projects going on in my head to keep me busy for an eternity, let alone an etching period. I like the copper chloride idea because it is sort of reusable with the addition of more h2o2, and it gives me a way of recollecting the spent copper. I can get whatever chemicals i need (lab grade hcl and h2o2) for free to make the etchant bath.
So disregarding the etching speed, is copper chloride solution a good way to go?
I can get a better marker type if need be, but I don't really wanna have to screw around with toner transfers.

Turkey9

Sat Sept 17 2011, 06:31AM

Registered Member #1451 Joined: Wed Apr 23 2008, 03:48AM
Location: Boulder, Co
Posts: 661

I've tried making it myself but it never seemed to work. I think it may have been that the solution was exposed to light and the H2O2 was decomposing. I didn't have any sort of a grasp on the chemistry going on when I tried it so you will probably have better luck.

I imagine the copper chloride will also be easier on the sharpie. No way to really tell until you try! I think that once you make a few boards and really see how wonderful it is you'll start wanting better and better boards. Markers are only good for big thick messy traces. I'd suggest at least trying another method be it photo resist or toner transfer or whatever you can manage.

Good luck!

Forty

Mon Sept 26 2011, 10:31PM

Registered Member #3888 Joined: Sun May 15 2011, 09:50PM
Location: Erie, PA
Posts: 649

got the boards, they look great. i recommend the ebay seller abcfab for all your copper clad board needs.
made a couple batches of the copper chloride solution. didn't bother with concentrated chemicals and just used 6M HCl and household ~3% peroxide.

one batch is really dark green (like it's supposed to be) and the other started green but then turned blue. I guess the blue means there aren't enough chloride ions in solution, but since the concoction reeks of chlorine, i think i just need to add more copper to get more copper chloride atoms in solution.

Killa-X

Mon Sept 26 2011, 11:12PM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

I know a sharpy wont hold up, unless mine was too thin but it got eaten away. Generally I just use high gloss photopaper and transfer it with an iron. My boards have always came out 100% flawless. At first they didnt, I didnt know the proper way to do it. So i used nailpolish. That stuff will not come off until you sand it, a lot. Else yeah, Ferric Chloride for me. Just use an agitator and come back later and its done.

I'm to the point now that I want to start using copper rivets and making my own double dided boards. =)

Forty

Tue Sept 27 2011, 12:40AM

Registered Member #3888 Joined: Sun May 15 2011, 09:50PM
Location: Erie, PA
Posts: 649

hmm. that gives me an idea to take a ~5mm length of small diameter copper tubing, put it through a hole in my double sided board, fan open the ends of the tube with a nail, and then hammer it flat into a rivet.
thanks :)

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