[sdiy] PCB making

[KA4HJH]

>Y-ellow Terry 'n' all.
>
>At 06:37 PM 1/2/07 -0500, KA4HJH wrote:
>
>>Model railroaders do the same thing before painting a brass locomotive.
>>It's called "pickling". You don't need to use etchant for this--any
>>moderately acidic solution will work but unfortunately I don't recall any
>>dilutions or times. Google might be a good place to start...
>
>Mmm. Sounds like there's more cats and skinning methods here. I'd often
>thought about methods for making front panels like this perhaps. Never put
>any to the test. Specially where Aluminium is involved. All kinds of nasty
>chemical reactions apparently. Terry is the chemist so I'm sure he'd be
>able to enlighten us. Hint Hint. And maybe this might spur him to think
>about other uses. Hint hint hint.

Yeah, I'm a "chemist" all right but not in the sense that Britons and
Australians usually mean.  8^D

I just paid attention in chemistry class in high school. I don't have any
credentials so I'm not qualified to be a talking head on cable TV news
shows.

Aluminum is an odd element. It's actually fairly highly reactive and has a
transparent layer of aluminum oxide on it if it's been exposed to the
atmosphere for a few minutes. Throw some in a reactive solution of some
sort and once the oxide layer is breeched you get--"interesting" reactions.
The kind that give off toxic fumes and heat and so forth. Or so I'm told.

>But the reason for using the etchant or caustic solutions is simply that
>they're handy. You need them to make the boards so it's just a matter of
>re-purposing them slightly.

Even scrubbing the blank with a pot scrubber will help, although using a
corrosive chemical does a finer and more even job. If the copper looks nice
and shiny with a slightly matte finish to it it's been pickled long enough.

>Makes me hanker for making some PCBs now just to try all this. I've got
>some TTS film somewhere. Remind me to kick myself back into reality later.
>PCB fabbing = too much trauma.

I always used the top of the dryer for etching and other chemistry
experiments. Ferric oxide just wipes off of porcelain. No stains for mom to
complain about.

-- 

Terry Bowman, KA4HJH
"The Mac Doctor"

"You know, I'll bet _any_ scene from "Metropolis" would have drawn protests
from football fans"--Roger Ebert