New to Self Etching

[justinheronmusic]

Hey all,
Just wanted to tap this resource before I start googling for some information. I am in the US and I am looking to start self etching boards. Where is a good place to buy copper sheets for this? Where can I get my chemicals? Aaaand, is there any advice, suggestions, or anything for someone who wants to get into etching their own boards?

 

[rock soderstrom]

Hey all,
Just wanted to tap this resource before I start googling for some information. I am in the US and I am looking to start self etching boards. Where is a good place to buy copper sheets for this? Where can I get my chemicals? Aaaand, is there any advice, suggestions, or anything for someone who wants to get into etching their own boards?

Self-etching PCBs is a fun activity and can be done in several ways.

My favourite variant for home use is the so-called toner transfer method (check youtube) with a cloth iron and Hewlett Packard laser printer paper for photo printing.

Other types of paper will also work, just try them.

As an etchant I use good old iron III chloride, which is very good-natured and fast enough for me. There are other etchants, all of which have their advantages and disadvantages. For the casual etcher, iron III chloride is quite nice.

As base material for the boards I use mostly single-sided Bungard PCBs with 35um to 70um copper layer, other brands also work.

You can get very good results with this process, I have attached a small example. At the beginning you have to try a little bit, but you can do it quickly and then you have your own process, which leads to very good results and it is really fun.



Since I don't live in the US, I can't say much about where you can buy the stuff you need. When in doubt, Amazon. But everything is easily available, nothing special.
Lets start etching!

PS: I use Acetone as cleaner, other solvents like mineral spirit will work, too.

PSS: I always buy (preferably expired = cheaper) photosensitive base material, because there the copper is protected by a protective layer. Simply wash off the coating with Acetone and you have virgin copper. Hmm, yummy!

 

[Brian Roth]

Decades ago I used to self etch PCBs. In my hometown (Oklahoma City) we had more than a few electronic stores catering to TV repairmen, Ham radio and similar hobbyists.

They all sold the materials for DIY circuit board creation. Nowadays, the one source I still see (without taking much time to search) for supplies is Jameco

https://www.jameco.com/shop/Keyword...earch_type_c=jamecoall&freeText=circuit+board
Back in those times, we didn't have laser printers so toner transfer wasn't an option. I used "pre-sensitized" blanks.

I etched the boards with ferric chloride. It's not totally toxic (and is still available) but it is a totally "messy" chemical that makes anything stained with an orange color...including fingers. So, use nitrile gloves!

Bri

 

[user 37518]

Self etching?

 

[JohnRoberts]

Back in the 70s i did some PCB work using ferric chloride etchant... I have no idea if that is still legal/available but now we can purchase prototype PCBs pretty cheap.

JR

 

[Brian Roth]

Back in the 70s i did some PCB work using ferric chloride etchant... I have no idea if that is still legal/available but now we can purchase prototype PCBs pretty cheap.

JR

Apparently ferric chloride is still sold after looking at the Jameco link I posted... shrug...not exactly a friendly chemical. If you experiment with self etching, beware it's not something you want to drink...LOL. "Bubba....hold my beer while I drink this concoction after I etched the PC board for my newest Neve clone!"

Back seriously now....as John mentioned I just use services like OshPark and a few of the Chinese companies for my recent PC boards. OK, if you want to mess with the complicated process go for it! I can add a few (OLD!) comments.

Bri

 

[Brian Roth]

@rock soderstrom .....

One problem when self etching I recall is the "naked" copper traces quickly corrode. In your pix, it appears you have an added layer. In Ye Olde Days, I used a product I recall that was named "tinnit" which applied a thin layer of tin atop the copper.

OK I'm not senile:

https://www.ceitron.com/tech/datak.html
Bri

 

[Brian Roth]

@justinheronmusic

How do you plan to create what we used to call the "artwork" used to make the "mask" for the blank copper clad material? I can remember/ramble on. Bishop Graphics "stickies" anyone? lol

Kicad here and send Gerbers to a vendor.

@MidnightArrakis I await your comments! <G!!>

Bri

 

[RuudNL]

I use sodium persulfate to etch PCBs. Works much cleaner!

 

[rock soderstrom]

Oh God, don't let these old farts stop you from doing your thing.

Ferric chloride is easy to handle and doesn't require any fancy safety methods. Safety goggles and maybe gloves for the timid, plus a paper pad, and you'll be fine. Yes, you should not drink FeCl3(H2O)x, so put your beer somewhere else ;-).

The process is not complicated, really. You can make your template/artwork with EasyEDA, it's free, easy to learn and very powerful.

I protect the copper of the tracks after etching with "soldering lacquer", just spray it on, works great (no corrosion). It protects the copper really well and improves the solderability of your board immensely.


Of course, you can have your prototypes made very cheaply in China nowadays, but if you only want to make a few PCBs, it's better to etch them yourself. You are simply faster, by the time the PCBs are back from China, you will already hear your work in your studio.

As I said, it's also fun.

 

[rock soderstrom]

I use sodium persulfate to etch PCBs. Works much cleaner!

Do you have to keep sodium persulfate at a certain temperature during etching or does it work well at room temperature?

I have actually never messed up anything (clothes and the like) with ferric chloride. I know the stories of ugly stains everywhere. If you take it slowly, nothing happens.

I am glad to see that there are still others who etch PCBs themselves.

 

[abbey road d enfer]

I used to do it with sticky transfers and chloric iron when it was the only DIY solution.
At first I used direct etching, i.e. the transfers were the protecting agent.
Later I built a UV insolating pad and used pre sensitized copper-clad.
Now I use JLCPCB in China or Aisler in Europe.

However, most of the DIY community seems to favour CNC engraving.
No messy chemicals, and drilling is done on the same machine.

 

[abbey road d enfer]

Do you have to keep sodium persulfate at a certain temperature during etching or does it work well at room temperature?

Heat increases etching speed.
When I started my company in a wooden shed, I put the chloric iron bath atop the stove. Good results were had with temperature around 20-40°C (70-120°F). Lower would make it excessively slow, higher would create bubbles.

 

[rock soderstrom]

However, most of the DIY community seems to favour CNC engraving.
No messy chemicals, and drilling is done on the same machine.

A good CNC milling machine is a fine thing. I have already had a look at it. However, the additional costs and the dirt and stench that arise should not be underestimated. It's not really practical in a small flat, you need a workshop, preferably with a suction unit and ventilation system.

 

[rock soderstrom]

Heat increases etching speed.
When I started my company in a wooden shed, I put the chloric iron bath atop the stove. Good results were had with temperature around 20-40°C (70-120°F). Lower would make it excessively slow, higher would create bubbles.

That's right, that's what I do (ca. 40°C, I use my hot air gun as heat source). However, iron III chloride is much more tolerant of low/high temperatures than other etchants IMHO, with which you have to keep the bath in a narrow temperature range, otherwise nothing happens or the etchant goes into self-destruction mode.

 

[gyraf]

My take on the subject - https://gyraf.dk/wp-content/uploads/2018/05/Making-the-PCB-Heres-how-to-do-it.pdf

But these days it's so simple and cheap to have boards made overseas that hardly is worth it - other than for the experience. Which counts..

/Jakob E.

 

[abbey road d enfer]

A good CNC milling machine is a fine thing. I have already had a look at it. However, the additional costs and the dirt and stench that arise should not be underestimated.

A good 3018 machine can be had for about 250€/$200. Of course one needs to add the cost of bits, which are much less expensive today than they were when I started doing PCB's (1960's).
Dirt is not a real problem because of its high density; it stays on the machine and does not fly.
Stench? Non-existant.

It's not really practical in a small flat, you need a workshop,

A 3018 CNC machine does not take much more space than your typical chloric iron bath, unless you have a vertical one, which costs as much as a CNC machine.

preferably with a suction unit and ventilation system.

Of course, but far from necessary.

 

[rock soderstrom]

A good 3018 machine can be had for about 250€/$200. Of course one needs to add the cost of bits, which are much less expensive today than they were when I started doing PCB's (1960's).
Dirt is not a real problem because of its high density; it stays on the machine and does not fly.
Stench? Non-existant.

A 3018 CNC machine does not take much more space than your typical chloric iron bath, unless you have a vertical one, which costs as much as a CNC machine.

Of course, but far from necessary.

Admittedly, I don't know all the current milling machines. I looked at a slightly larger model at a buddy's place, the idea was to use it for labelling front panels as well. Matching machines were more like 500€ upwards 5 years ago and yes, they made fine dust and stench. My etching bath doesn't do that.

No doubt there are many useful ways of prototyping boards, my process fits my low demands as a hobbyist perfectly.

 

[rock soderstrom]

A 3018 CNC machine does not take much more space than your typical chloric iron bath

I just had a look at the model you mentioned. They are really very cheap. Are they any good?

Edit: If I were going in a similar direction, I would probably buy a laser engraver/cutter today. But they really stink!

 

[rock soderstrom]

and drilling is done on the same machine.

This is a big plus, because drilling is the most time consuming/ boring part in my process.