Homebrew PCBs

M&G lists sodium persulfate as an alternative to FeCl. Anyone tried 
it? I've already read the archives and haven't seen any actual use. 
Most alternative etchant use seems to have been ammonium persulfate 
which although clear and allows viewing the etch progress apparently 
is difficult to store over time...especially in plastic.

How difficult is sodium persulfate?

tnx
jtm

It's basically the same stuff as far as performance.
Rick

mdgolfbum wrote:

>  M&G lists sodium persulfate as an alternative to FeCl. Anyone tried
> it? I've already read the archives and haven't seen any actual use.
> Most alternative etchant use seems to have been ammonium persulfate
> which although clear and allows viewing the etch progress apparently
> is difficult to store over time...especially in plastic.
>
> How difficult is sodium persulfate?
>
> tnx
> jtm
>

FeCl is a big stainer
> but keeps well. Any info on SP like shelflife, disposal issues,
> staining, smell?

No smell, no staining, shelflife is 2 weeks. You cannot reuse if like FeCl.
Heating it tends to make it work much better.

Here is a link to disposal.
http://www.kepro.com/fmc4.htm

Thanks
Ron

Rick

Thanks for the quick response. Any benefits? FeCl is a big stainer 
but keeps well. Any info on SP like shelflife, disposal issues, 
staining, smell?

tnx
jtm

The crystals unmixed will keep indefinitely. Once dissolved and the
cayalyst added, it will begin to slowly weaken. I have mixed a portion
of solution and did a small board. Left it in the tray for a few weeks.
Came back and heated it and did two more boards. I don't think it would
last too much longer than that. Although once I let the solution dry up
into crystals again and I just added water and it still etched a board
when heated. It doesn't stain or smell. It looks like blue Windex when
used up. I just pour it into a 5 gallon bucket and let it dry into
crystals. Once I get a lot of it (I mean a lot, which takes years), I
put it into a  plastic bag and take it down to the landfill where they
have a hazardous waste day for disposal.
See my webpage.
Rick
http://www.pic101.com/pcb


mdgolfbum wrote:

>  Rick
>
> Thanks for the quick response. Any benefits? FeCl is a big stainer
> but keeps well. Any info on SP like shelflife, disposal issues,
> staining, smell?
>
> tnx
> jtm
>
>

In a message dated 3/21/2004 6:40:15 PM Central Standard Time, 
jim@... writes:
ammonium persulfate which although clear and allows viewing the etch progress 
apparently is difficult to store over time...especially in plastic.
Whew!  Yep, I bought a few lb. of that stuff (dry form) from Kepro when they 
were still alive.  Came in a plastic "tub" with snap-on lid like cheap 
Tupperware.  Put it on a top-shelf of a book-case in my lab.  MISTAKE!  In a few 
months, it ate through the tub and, drawing moisture from the air, made a goo that 
slithered down all among books, wood, and carpet.  Made a mess!  I decided I 
do SO few PC's, I'll stick with R.S.'s FeCl-3 ! ! ! 


[Non-text portions of this message have been removed]

I have made over 10,000 home made boards in my lifetime and I speak from
experience. The crystal power will keep indefinitely. I have never had a
problem storing the powder. I bought a 5 gallon bucket of A.P. from
Kepro. I took a few plastic containers and filled them for smaller
storage. Some were open, some were tightly sealed. Never had a problem
with any of them. It is the best, cleanest, and safest to use. I used to
use FeCl in earlier days. I will never touch that stuff again. It stains
everything it comes in contact with, splashes are hard to control, it
eats its way theough clothes, and storing and disposal is harder.
Rick
http://www.pic101.com/pcb

"Rick C." wrote:

>  The crystals unmixed will keep indefinitely.

One thing I noticed years ago with this was that the catalyst ate through
the Sanford Sharpie ink I was loading my plotter points with. Without the
catalyst, it was fine, but took forever to etch.

Mike Nash

----- Original Message ----- 

From: "Rick C."
Sent: Monday, March 22, 2004 6:24 AM
Subject: Re: [Homebrew_PCBs] Re: Sodium Persulfate?


> I have made over 10,000 home made boards in my lifetime and I speak from
> experience. The crystal power will keep indefinitely. I have never had a
> problem storing the powder. I bought a 5 gallon bucket of A.P. from
> Kepro. I took a few plastic containers and filled them for smaller
> storage. Some were open, some were tightly sealed. Never had a problem
> with any of them. It is the best, cleanest, and safest to use. I used to
> use FeCl in earlier days. I will never touch that stuff again. It stains
> everything it comes in contact with, splashes are hard to control, it
> eats its way theough clothes, and storing and disposal is harder.
> Rick
> http://www.pic101.com/pcb
>
> "Rick C." wrote:
>
> >  The crystals unmixed will keep indefinitely.