rmeyn
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My primary interests are electronics, sailing, bowling, and camping
Posts: 163
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Post by rmeyn on Aug 12, 2008 7:53:29 GMT -8
Hi all, There seems to be interest in lifting circuit board diagrams or using software to create diagrams for printed circuit boards. Then there is that eching problem. For years I've use the Ferric cloride method to etch them. Radio Shack has discontinued this item (it was over priced anyway) I decided to try the Hydrocloric acid/ peroxide method. My wife is a chemist and helped me with the mixing. I was absolutely amazed how well it worked, how cheap it is to make, and how the etchant solution can be used over and over. Also, it is more environmentally friendly and easy to dispose of.
Mix 2 parts 12 molar Hydrocloric acid with 1 part 3% Hydrogen peroxide. The 3% hydrogen peroxide can be bought any pharmacy for less then $1.00 per 500 ml bottle. The 12 molar HCl acid can be bought at a chemical supply store or at your local building center (get the Muriatic acid used to clean bricks)
Add the acid to the peroxide slowly. Use a glass container only. Do it outside and don't breath the fumes. Store it in a glass bottle with a cap. Don't shake it.
Etch your pcb board as usual. The solution will turn green as it works. It's fast and when done, return the solution to its storage container. When the solution turns brown, add more peroxide, and the solution can be used again and again. When it comes time to dispose of the etchant, neutralize it with baking soda and throw it out. Give it try. When you do, you will never go back to Ferric cloride. rmeyn
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Deleted
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Post by Deleted on Aug 18, 2008 21:56:10 GMT -8
Thanks
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Post by Deleted on Sept 10, 2008 15:09:00 GMT -8
I to use muriatic and peroxide with great results. I mix it in a good quality ziplock bag. Then I slip the board in and zip it up. No fumes! I sit the bag in a sink of hot water. The heat makes the acid work great. If it gets to cool I just add more water to the sink. It is easy to agitate the board in the bag. I have found that if I hold the board by its edges through the sides of the bag and use a system of lifting the bottom of the bag to allow the acid to cover the board then lowering it to allow the board exposure to the air in the bag for 5 seconds or so, the copper etches fast and clean. When done I move the board to the top of the bag, unzip and slip it out. I etch tracks to .5mm on 1oz copper using toner transfer successfully. Bazza.
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rmeyn
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My primary interests are electronics, sailing, bowling, and camping
Posts: 163
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Post by rmeyn on Sept 10, 2008 18:26:33 GMT -8
Thanks. I will have to try that technique. Muriatic acid (hydrocloric acid )and peroxide really do work well. I'm having trouble soldering very fine lines. Apparently oxidation occurs very quickly. I might try that "liquid tin" I see listed in Allied Electronics and elsewhere. It plates a very thin layer of tin over the copper after you are through with etching. Supposed to make soldering much easier. rmeyn
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Post by Deleted on Sept 11, 2008 16:47:47 GMT -8
What I do is as soon as its out of the acid and cleaned with water I then acetone to remove the toner, I then drill holes, I then give it a quick run over with a scotch brite and dish soap. A quck rinse with hot water, a wipe with a paper towel. I then tin it straight away by using liquid flux over about a 2 x 2 inch square and use an iron with a chisel tip.If you try to do more area than a couple of inches the flux tends to dry before you get to it. The board will tin as fast as you move the iron. I mostly do surface mount stuff so when I have finished tinning the whole board, I then run solder wick over any spots where chips with large numbers of leads go to make sure I have a perfectly flat surface. I then give it another scrub with a scotch brite and dish soap. Bazza.
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rmeyn
Full Member
My primary interests are electronics, sailing, bowling, and camping
Posts: 163
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Post by rmeyn on Sept 12, 2008 5:20:34 GMT -8
Many thanks for the tips. Will give them a try. Rmeyn
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Post by Gary Lecomte on Sept 12, 2008 6:40:15 GMT -8
I haven't found Tinning Any better than just plain copper. Both these will Oxidize, resulting in Poor Soldering ability.
However, MOST Important is a "CLEAN BOARD". And NEVER TOUCH THE COPPER TRACES WITH YOUR FINGERS!
I first Remove the Resist Coating, cleant it a bit so I can drill it. Than I Scrub it clean with an "SOS" Pad. Lastly I rinse it Really Good with Hot Tap Water and IMMEDIATELY DRY IT.
A Fast, Hard Jet of water is Best, so to make sure all Soap gets removed from the holes.
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rmeyn
Full Member
My primary interests are electronics, sailing, bowling, and camping
Posts: 163
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Post by rmeyn on Sept 12, 2008 10:11:32 GMT -8
Why has not someone invented a spray on product that will stop oxidation and still allow soldering? Sometimes it's days before I get around to soldering and, invariably , during that time some oxidations occurs. rmeyn
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Post by Gary Lecomte on Sept 12, 2008 18:21:56 GMT -8
Why has not someone invented a spray on product that will stop oxidation and still allow soldering? Sometimes it's days before I get around to soldering and, invariably , during that time some oxidations occurs. rmeyn Wrap the boards "Tightly" in "Handy Wrap" or any simular product and they should stay bright for weeks, Even Months. Where I live, its Low Humidity (35% Average) and even without wrapping them they are good for many weeks. Other than that, a QUICK Rince with delute HCL, Followed by as repeat wash in water, will get the Shiny very Quickly.
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Post by abdulmajeedtahir on Sept 19, 2008 2:32:58 GMT -8
I seen electro each tech. but i cannot understand how I print tracks on coper clade board is the screen mathod will apply with PVC screen printing ink or what is other way to apply each resist, also i want to know how much volt dc and what is the current will apply whey start eaching? Thank you
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Post by Gary Lecomte on Sept 19, 2008 6:35:25 GMT -8
I seen electro each tech. but i cannot understand how I print tracks on coper clade board is the screen mathod will apply with PVC screen printing ink or what is other way to apply each resist, also i want to know how much volt dc and what is the current will apply whey start eaching? Thank you I Don't understand "PVC" Screen Printing Ink. I Assume you mean using a "Laser Printer", than Ironing it onto the copper. I Don't do that as it isn't practical for making production quantities, as I need to make. I use "Shipleys Auto Positive Resist". It is a Ultraviolet Light sensitive coating that is Available in the USA. But I Really Doubt you can get this in your Country, so there is no point in me going into further details about using it. As to My Electro-Etch Process, that I use. Current can be as much or as little as you want. The Greater the Current the Faster the Etch, BUT if the solution gets TOO Hot, The Resist may Fail, Causing a Poor Etching job. Since I Don't use the Laser Printing, I also don't know how well it will work with my Electro-Etch system. I typically use about 1/2 amp per Square Inch of copper. (Temperature also depend on the Volume of Water in your etching tank.) IF your going to Try this, You will need to Experment a lot to get the best results. Gary
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Post by ubakeluyuzoji on Nov 19, 2019 8:05:29 GMT -8
Junk
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Post by volkswagenvan on Nov 19, 2019 8:54:05 GMT -8
Junk
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Post by Don on Apr 4, 2020 18:15:46 GMT -8
Why has not someone invented a spray on product that will stop oxidation and still allow soldering? Sometimes it's days before I get around to soldering and, invariably , during that time some oxidations occurs. rmeyn In your area, is there a product called 'Gibbs'? www.gibbsbrandlubricant.com/ I have used it for several uses. It will prevent corrosion, but I haven't tried it yet for soldering.
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Post by volkswagenvan on Apr 4, 2020 23:50:20 GMT -8
Thank you for the input Don.
I just get the boards warm and put a thin layer of plain old candle wax on them. (You can't even see it) Did it for years with no problems! It will stop oxidation and still allow soldering just fine.
Easy trick!
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