Usually my issue is that the feature size I need is only barely within the capability of a hand-made board. Often it’s smaller-- so if I need it quick, it’s just a more expensive order to Advanced Circuits.
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I use this process (muriatic acid + hydrogen peroxide) for my etching. It takes MUCH longer than ferric chloride. For me that isn’t an issue since I’m not usually in a hurry. it does also require some babysitting. It need to be stirred occasionally to keep working well.
It is definitely much much cheaper, and disposal is easier, but the trade off is the amount of time it takes to work.
I’ve used it as well. Oddly, the first time I did it it didn’t take much longer. After that it did. I must not be doing the regeneration part correctly.
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The key is to get enough copper dissolved into the solution; the correct solution is not just acid and hydrogen peroxide. Try using an aireator to speed up the oxidation reaction while dissolving some stranded copper wire. Initially it takes a lot more copper than you would expect. Once you get enough copper in the solution it can be regenerated by simply running the aireator in a well ventilated area. I have some of the solution if anyone is interested. My boards etch in times similar to FeCl and I never need to dispose of the chemical.
As long as what to bring in you take out, hazardous waste (as defined by city, county, state, federal) and it’s disposal shouldn’t be a problem. What you do in the privacy of your home … well, it’s private. But pouring anything on their lists can’t be dumped down any of DMS drains. This is one of those nasty strict laws that can have serious problems for the Space.
What may be benign at the start, after the chemical reactions, may not be. I’m love to do anodizing - same issues. At least we will at some point have chem hood installed so the hazardous vapor issue is mitigated.
I’m curious if there is a way to test for this other than timing how long it takes to etch? Since my etchings take a really long time, I’m guessing I don’t have enough copper dissolved in it yet.
Thanks for the info. I’ll have to try using an aerator.
In the commercial world I worked in, they had tables made that had the chemical concentrations, volts-amps-wattsever, material type, surface area, temperature, aerated vs non-aerated, etc. They would would then test the chem strength and know how long to go based on the amount of material to be removed.
I’m guessing this is a LOT more work than you’re looking to do. Might be able to find the info online.
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Aquarium pump works perfectly.
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I strongly advocate that no one should be disposing of copper containing enchant in a drain at home or anywhere else. That’s the whole point of this enchant method. I’ve had the solution for over 10 years and have not poured out any of it. Most cities have disposal programs for home owners if a person decided they no longer want the enchant around the house.
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Take a look at Table 3 in this exhaustive write up; you can test for specific gravity. Nothing too hard or exotic but does require a unique tool.
Thank you, that sounds simple enough to try.
Instead of immersing the board you can make a small amount (about 1/2 cup) of the solution and sponge the copper off the board. Much faster.
Anyone tried blasting the copper off with a laser? I wonder what wavelength copper absorbs.
Copper makes a really good IR reflector. Please don’t try it.
It doesn’t work with the CO2 lasers. I have used the laser to etch paint on the board and then use acid. I did manage to mark the copper but the heat caused delamination. It’s possible to laser etch but requires a different type of laser.
Which is the root of my question: What kind of laser does it take? Anyone have some solid references to this?
Nd:YAG lasers can be used to etch & cut metal at moderate powers. It’s part of the reason I’ve continually lobbied for one.
Some of the LPKF laser PCB prototyping machines use a wavelength of 532 nm. Others use UV (355nm) which I think are Nd:YAG lasers as publius said.
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