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Forum Index : Microcontroller and PC projects : Etchant
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9067 |
What's wrong with Ammonium Persulphate again? I'll have to read back through the thread a bit, to see why that was not an option. Might simply have been cost, but as Mick says above..... EDIT: Just cost and easy substitution for Ammonium Persulphate as per post #1. I get my Ammonium Persulphate from Jaycar - it seems to be reasonably priced. Ferric Chloride stains anything it touches, so that was one reason I dropped it in favour of Al.Per. But Ferric Chloride etches at room temperature, from memory, whereas Al. Per. has to be heated to about 70'C or it won't etch at all. Smoke makes things work. When the smoke gets out, it stops! |
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bigmik Guru  Joined: 20/06/2011 Location: AustraliaPosts: 2870 |
Lads, I, when I used to make my own PCBs, used to use Ammonium Persulphate. It works, was cheap and didn't make as bad a mess as Ferric Chloride used to. I used to store it in old soft drink bottles, when it was noticeably blue then you toss it out as it wasn't very effective anymore. Of course, as most teenagers did, I would NEVER discard it by pouring down the drain or on my mum's favourite plants. Would I? 
It IS a slower etchant and for best results should be warm, I guess around 30-40 deg C. Regards, Mick Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<< |
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Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1211 |
I use that AP ( bugger spelling it ) and all I do is let the water evaporate then put the crystals in a jar for later disposal. Now I got my cnc going all boards in the future will be milled now I got some beaut carbide engraving cutters off fleabay. Besides going the etch method using AP seemed to take ages and a 1500 watt heating element working off my shed bank did seem a BIG waste of power. |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1328 |
Interesting it went bright orange when you mixed it Paul - you didn't mention that before. Most likely that was due to iron contamination (ferric salts) in the acid - iron is a common impurity in industrial HCl (which builders often use because it's cheaper). Most pool HCL is pretty low in iron because it can stain the pool if the pH gets a bit too high. The pool shops often tout the 'low iron' in their HCl as a reason for the high price - but they do have a (small) point there. I'd be very surprised if iron was the reason for the explosion though. Some other impurity elements would be more likely if they were in high enough concentrations. Greg |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1328 |
Nothing particularly Grogs - apart from the fact it's slower and needs warming. I think I remember reading somewhere once that it's more inclined to 'undercut' the copper from the resist, compared to ferric chloride but I doubt that's very relevant for us. Greg |
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