Just curious, what is the difference between Ammonium persulfate (expensive $32/kg) and
Ammonium sulfate ($9.49/20lbs bag at Walmart)?
Jean-Paul
N1JPL
> On Mar 22, 2016, at 2:54 PM, 'K5ESS' k5ess.nothdurft@... [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote:
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> If I read the material correctly on using ammonium persulfate as an etchant; one big drawback is that it has a fairly limited shelf life. It will lose its potency in thirty days or less just sitting on the shelf. For the infrequent user this means making a new batch each time you want to etch a board. That combined with a fairly high cost tends to make not too attractive.
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> Many may have visited this site but here’s a good discussion on various etchants.
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> http://www.pcbfx.com/main_site/pages/accessories/etchants.html
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> Mike N.
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> From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
> Sent: Tuesday, March 22, 2016 10:06 AM
> To: Homebrew_PCBs@yahoogroups.com
> Subject: Re: [Homebrew_PCBs] Re: Mark-8 'Non-plated through holes' and 2 sided PCBs
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> On Mon, 21 Mar 2016 23:47:54 -0700, you wrote:
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> >According to a search, MG Chemicals sells ammonium persulfate. In my area Fry’s Electronics says they have it for $32/Kg. I hadn’t thought to look there.
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> That's very very expensive. You'd possibly get better prices from a
> chemical supply house. The etching tank I have needs about half a kg
> per load. Not in the least competitive with CuCl.....
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> Harvey
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> >Andrew
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> >From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
> >Sent: Monday, March 21, 2016 6:54 PM
> >To: Homebrew_PCBs@yahoogroups.com
> >Subject: Re: [Homebrew_PCBs] Re: Mark-8 'Non-plated through holes' and 2 sided PCBs
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> >I used it for a short time. I loved that I could see the etch process through the solution. I think I stopped because I couldn't get it any more.
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> >On 3/21/2016 4:35 PM, 'keith printy' keethpr@... [Homebrew_PCBs] wrote:
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> >Anyone here besides me ever use ammonium persulfate? When I worked in an electronics plan that was what we used to etch our boards. We would put it in a corningware baking pan and put it on a small hotplate to keep it warm. It was fairly quick depending on what concentration you used . it is an oxidixer ,mix with sugar and heat it goes boom!
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> >From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
> >Sent: Sunday, March 20, 2016 2:53 PM
> >To: Homebrew_PCBs@yahoogroups.com
> >Subject: RE: [Homebrew_PCBs] Re: Mark-8 'Non-plated through holes' and 2 sided PCBs
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> >Where is nitric acid found? Is it practical compared to HCl/H202 or FeCl?
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> >From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
> >Sent: Sunday, March 20, 2016 2:26 PM
> >To: Homebrew_PCBs@yahoogroups.com
> >Subject: [Homebrew_PCBs] Re: Mark-8 'Non-plated through holes' and 2 sided PCBs
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> >I do RF PCBs requiring micro strips etc. It must use double sided FR4 boards with consistent permittivity and very accurate trace thicknesses for impedance matching or inductance chokes.
> >The hackaday technique assures such results repeatably.
> >All acids must be handled properly, I have 30 years experience with conc. NITRIC and never a problem. HCL is also dangerous, fumes, and can emit large volumes of chlorine if it comes into contact with household ammonia cleaners.
> >http://www.flinnsci.com/media/396140/acidsafety.pdf
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> >When nitric is etching copper it bubbles a bit and self stirs the mix for cleaner trace edges I have found. Also the fine even bubble generation reveals any improperly cleaned copper areas within a couple seconds. Such areas can lead to longer immersion times which will cause over etching of the properly cleaned areas. In effect it gives me quality control feedback that other etchants don't.
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> >Further, the copper nitrate end product is beneficial to sewer systems for restricting root growth, a fungicide or as a soak for preserving outdoor wooden surfaces.
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> >∗ Cupric Nitrate (Copper Nitrate) Cu(NO3)2·nH2O, green powder or blue crystals which is soluble in water; used in electroplating copper on iron; as a catalyst and nitrating agent in organic reactions; component in rocket fuel; fungicides and wood preservatives; textile dyeing and printing; pigment in ceramics;
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