Thank you for affirming my contentions. I will never go back to FeCl even if I run out of A.P. Once the solution is spent, I dump it into a 5 gallon pail in my garage and let it evaporate into dry crystals. It takes many dozens of gallons of old solution to fill a plastic quart jar of crystals. I then wait for our county landfill "hazardous waste disposal day" and take it there for disposal. Rick http://www.pic101.com/pcb Phil wrote: > There was a bit of discussion about AP a while ago and now that I > have had about a month of experience with it, I thought I'd report > back. > > I had a number of misgivings about AP based on comments posted here > but since I had bought it, I figured I'd use it... > > My set up. A vertical tank that holds 1 L, a heater that brings the > temperature to 100F and a bubbler. All my boards have been double > sided so there was lots of copper to etch. > > Issues that had been raised: > - short shelf life of AP solution. I've been pouring it out of the > tank and storing it in a glass jar. So far i have done 12 boards and > it appears to be still quite potent after a month. The last board > etched in about 13 minutes, just like the first one. I did have a > huge crystal (Cu sulfate?) form in the bottom of storage jar. Kind > of pretty. > - toxicity/fumes. While I haven't been making cocktails with it, I > can say that I've experienced no problems or skin irritation. > - cost. ya got me there, its about twice the cost of FeCl > > Some of the benefits of AP: > - clear. I can easily monitor the progress of the etch. > - non-staining. I spilled a little on a wooden benchtop and some > paper. neither took more of a stain than water. > - the powder is not exothermic when mixing with water. FeCl is > really nasty that way. (I'm sure I'm using the incorrect term here, > it releases a LOT of heat when mixed with water) > - I believe it has more etching capacity than FeCl. I've done twice > as many boards as with my last batch of FeCl (1 L, too). This is a > subjective opinion and could be completely false... > - pretty blue color > > If I had to get some new etchant today, I think I'd experiment with > HCl+H2O2 but AP is a fine etchant to use and I'm very happy with it. > >
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Re: [Homebrew_PCBs] My experiences with Ammonium Persulphate
2004-04-09 by Rick C.
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