sodium persulphate

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i wanna try and get my hands wet with doing some home PCB fabrication and from what ive read, sodium persulphate seems to be the chemical of choice for stripping copper from a pcb. I plan on using the toner transfer method. Ive found several stores locally that carry ferric chloride, but i hear its not too good, and very messy -- Does anyone know any type of places that locally might carry this chemical, or do i need to order it online, and if so, who has the best prices??
below is a link to the chemical i speak of,

http://www.mgchemicals.com/products/4101.html

I did find a local MG chemicals dealer, and i went to the store, however they dont stock the chemical and refused to order some for more unless i wanted a case -- so that route wont work ...

thanks in advance,

-chris
 
GC Electronics sells it in Pint and Quart sizes. This is what I use at home.

For fastest results float the PCB upside down in the heated solution. This way the weight of the dissolved copper will cause it to fall away from the floating board and there will always be fresh echant working on the copper. You should be able to etch a standard 1-oz copper board in about 15 min this way. If you can't find a dealer let me know and I can give you details to buy it through my supplier in SLC.

Mark
 
I've been trying to locate the sodium persulphate myself, but to no avail (This stuff does not seem to have been around for very long). I've been using ammonium persulphate and it does a good job, but it does dissolve some of the supposed etch resistant pen. It is definitely cleaner than ferric chloride.

If you want to etch really fast at a relatively low cost, I suggest a trip to your local Wall-Mart (or other commodity store that carry all sorts of stuff). What I did (with better than good results) is take a plastic juice container (preferably thin, mine is about 10 inches high, 9 inches deep and 2 inches wide and contains about 3L of etching solution). The next thing you need is an adjustable aquarium heater in the range of 100-200W. While in the aquarium section, grab a bubble stone, an air pump and some hose to plug in between.

For a grand total of about $20 you have an etching tank just as fast as the $600 commercial solution. Normally the aquarium heater won't allow you to go any higher than 90F, but with a little tinkering (I removed the lock preventing the adjustment button from turning higher) I got mine to heat the solution up to 115F. Make sure you fasten the bubble stone to the bottom of the container, preheat your solution and you're ready to etch in about 15 minutes. Once hot, a 2oz copper board will etch in approximately 4 minutes).

The toner transfer so far has also given me good results. For large traces, regular photo paper does the job, for more delicate stuff, I use the Techniks Press and Peel Blue. So if you're having a rough time with regular paper, I suggest trying this specialized paper. It is costly but does a better job. (and it is definitely cheap compared to having those pcbs done in a fab) I believe that timing is 90% of the work when doing the toner transfer. Your iron should maintain a temperature of about 300F and heat your board for at least a minute, a minute and a half. I usually go for 2.5 minutes with rather good results. Shorter times will leave some spots untransfered and too much will burn the paper into the toner making it very hard to remove.

Hope these little bits of info will help you in your first experiments.
Sébastien
 
thanks for the info guys -- the aquarium / heater / blower is a great idea, i will definitely look into it -- i have found one dealer online. Mark, thanks for the info on GC electronics, the vendor list shows a few near me, ill have to give them a call and see if i can pick some up -- thanks alot again

-chris
 
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