Re: [Homebrew_PCBs] Re: Sponge etching with HCl and H2O2?
2011-11-27 by Piers Goodhew
Still, if something can be reused, no shame in that. I've been to nz several times. It was great except all the cakes were unleavened due to the prohibitive cost of NaCO2... PG Sent from my phone, anything lewd or incomprehensible is probably autocorrect and not my fault. ----- Reply message -----
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From: "tda7000" <Tda7000@...> To: <Homebrew_PCBs@yahoogroups.com> Subject: [Homebrew_PCBs] Re: Sponge etching with HCl and H2O2? Date: Sun, Nov 27, 2011 3:28 pm No worries, I can understand your point of view. However having never actually purchased any I had no idea of the price, nor do I live in USA and in my country (New Zealand) things can be a bit of a ripoff. For example, You can buy this (almost 1 litre) of hydrogen peroxide for $2-3 (http://www.instructables.com/id/Stop-using-Ferric-Chloride-etchant!--A-better-etc/#step1) but it costs me $3.50 just for 100ml (about 10 times the price!) No local shop sells more than 100ml bottles either, you can special order larger ones but the price is even worse for some reason. (have they not heard of bulk discounts?) Take the HCl too, according to that instructable, "The acid I got is 31.45% (or 10M) and should run around $5 per gallon" Google tells me 1 US gallon = 3.7 litres, yet 1 litre of HCl here is $18. That would make 3.7 litres around $60! You don't want to know the price of liquid tin crystals! (nobody sells the liquid itself)- not that I buy them, of course. Some cheap flux and a soldering iron is what I do in the way of tinning. I don't know if the prices for your chemicals are that cheap everywhere in USA, so I'm sorry if I am wrong there, but in comparison they do not seem very cheap here. However a quick look online suggests the baking soda IS pretty cheap, so I guess that part wouldn't be too bad... thanks for the advice, I guess once you used it you couldn't use it again anyway. --- In Homebrew_PCBs@yahoogroups.com, Roland Harriston <rolohar@...> wrote: > > Sometimes, I am truly amazed! > > A pound box of Arm and Hammer Baking soda costs about a dollar-fifty in > any supermarket in the USA. > Cheaper at WalMart. > > If you live in the high altitudes of Nepal or Tibet, and you have to > ride your yak down a mountainside to buy a box, then you might think > about saving > the cost of an ounce of bicarb. > > Sorry.........I just could not resist. > > Roland F. Harriston, P.D. > ******************* > > tda7000 wrote: > > > > > > Thanks - I guess then that just a water rinse isn't good enough? > > Also, do you re-use the baking soda mixture or make a new lot each time? > > > > --- In Homebrew_PCBs@yahoogroups.com > > <mailto:Homebrew_PCBs%40yahoogroups.com>, "leeleduc" <leeleduc@> wrote: > > > > > > > > > > > > > > > > > > > > > One thing I should mention. I keep a bowl with about 1 quart of > > water and 1/4 cup of baking soda dissolved in it. When I'm done, I > > toss the foam brush and any tools I've used into the bowl to > > neutralize any acid on them. I do the same with the PCB, quick dip in > > the bowl and a quick rinse under the the tap and I'm good to go. > > > > > > --- In Homebrew_PCBs@yahoogroups.com > > <mailto:Homebrew_PCBs%40yahoogroups.com>, "tda7000" <Tda7000@> wrote: > > > > > > > > Sounds good, I think I will try that. Like the idea of a foam > > brush, should be easier to use than just a kitchen sponge and less messy. > > > > > > > > > > > > --- In Homebrew_PCBs@yahoogroups.com > > <mailto:Homebrew_PCBs%40yahoogroups.com>, "leeleduc" <leeleduc@> wrote: > > > > > > > > > > I use this technique all the time. I can do a 4X6 inch board in > > about 2 minutes. I use 1 Part HCL and 2 Parts 3% H2O2. I make just > > enough etchant to cover the board about 1/8 to 1/4 inch and lightly > > brush the surface with a foam Paint brush. I etch at room temperature. > > Works very well for me. > > > > > > > > > > I've also tried 1 part HCL and 2 parts 12% H2O2 but the reaction > > was too fast and hot to control easily. > > > > > > > > > > > > > > > > > > > > --- In Homebrew_PCBs@yahoogroups.com > > <mailto:Homebrew_PCBs%40yahoogroups.com>, "tda7000" <Tda7000@> wrote: > > > > > > > > > > > > I see some people get very fast etch times with a sponge and > > ferric chloride... > > > > > > > > > > > > But has anyone tried that method with the HCl and H2O2 > > solution, or the cupric chloride? > > > > > > > > > > > > Or anything else for that matter? > > > > > > > > > > > > > > > > > > > > > > > > > > [Non-text portions of this message have been removed] > [Non-text portions of this message have been removed]