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billy

PCB Etching Tank - Do it yourself

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Hi guys I have been reading with interest the various methods of etching a board,I have tried most of them over the years and my final equipment is a plastic bucket that I put the board in etching face up ,pour in about 10mm of ferichloride stand it in some warm water and agitate,a swirling action is the best,I find the board will be etched in about 3-4 minutes. Total equipment cost 2$. Another tip if you are making a UV exposure box,use the UV tubes that are sold for Insect sappers,also sold for killing mosquitos, and seen in most butcher shops, these tubes are a fraction of the price,you can also get them in a U shape which will give a bigger area of light.If you are not conversant with wiring these tubes get an electrician to do it for you,or run them from a home made inverter.I do all my artwork with cad drawing,or in the case of good quality art work that is published copy and print on a inkjet printer ,5 minutes on my uv light box with presenstised board gives good results,with most  presensitised boards they supply a developer that is quite expensive ,try using sodium hydroxide 20 grams to 1 litre,very cheap,use at about 20degrees centigrade .  I printed the artwork for the 0-30volt power supply and had it etched and drilled in 4 hours.Hope this has been useful.       

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I already etch lots of one off boards, current process is printing onto tracing paper, UV exposure, develop and etch in a plastic tray. This would be fine if I didn't share a house with four other guys. If it could go a bit quicker and be a bit more "self-contained", I'd get in the way less.

Thanks for all the help, sorry I was a bit insistent. I was sure it would work, I just like to understand why.

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1. Slightly oversize a pyrex glass tray to the copper clad board.
2. Pour some common Ferric Chloride in the tray and place your board in the latter solution.
3. Every 20 min using your hand lift one side and allow the ferric to wave over the board.
4. After 1 hour your board should be complete (depending on size).
5. Using tongs remove board and flush with water, clean resist from PCB.
6. Pour the Ferric back into its bottle and use on the next project!
7. Clean tray with water and allow the faucet to run for 45 sec - min (flush pipes).

The above process has been used since the dawn of time, why try to reinvent the wheel.
Furthermore, when making a PCB at home remember it is an enjoyable hobby, time is not a big concern...  :)


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The above process has been used since the dawn of time, why try to reinvent the wheel.


Electronic parts are much smaller than they were at the dawn of time. There are new requirements to make traces much closer and the parts have all gotten smaller. If you etch one of the newer footprints for one of the surface mount chips with closely spaced pins in a cold bath that will take an hour, it will undercut the traces and pads leaving a layout that is not useable. As technology changes, you must change with it. It is not just about the time.
Also note that the etchant is trying to get through your pattern as well as the copper. You will have to make sure your developing process was real good if you are going to subject it to an hour of etching. The longer you etch, the more light flaws from your original pattern will show up. With a faster etch, the solution is a little more forgiving of these flaws.

MP

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MP,

I mean no disrespect concerning my statement.

The majority of hobbyist use the typical component size, i myself avoid using surface mount which would require more detail concerning PCB design along with the control method of etching.

Truthfully, i never expect to duplicate a printed circuit board manufacturer nor would i waste the money in trying.
Being able to make a decent PCB along with a pseudo tinning process is more than enough.
The few flaws that appear in the copper is a part of the process that give's the board a home made character.  ;)

Like an old wooden floor that has a few squeaks.  ;D

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No disrespect taken. Just pointing out that more precise methods of board manufacture that are available today are not really a re-inventing of the wheel. Whatever makes my work easier is ok with me.  ;D

MP

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I've built one too.

But since i discovered Hydrogen Peroxide + Muriatic Acid, i just don't use it anymore.
You can find (at least here in italy) Hydrogen Peroxide 40% vol from airdressers, it is present in the products they use to make air shiny blonde.

I just lay the pcb in the plastic box and cover it with a small amount of muriatic acid (just enough to cover the pcb), then i squirt a small amount of air product and wait around 10 minutes, less if you give it a little shake sometimes.

I agree that this solution is far more dangerous than using ferric cloride, but if the right precautions are taken, you save a lot of money:

- No pcb tank nedeed, just a little plastic box (the mixture i mentioned above is very powerful in very little quantity)
- 10 minutes maximum etching time, even for large pcbs, i had perfect results in less than 10 minutes without eating nor shaking.

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