PCB Etching

[ChrisGreece52]

Hello guys im relatively new in electronics and i would like to start etching my own pcb's but i came to a problem. What ways are the most cheap and effective?
Also another thing is the equipment.
I do not have a laser printer nor a drill (but i can get one motor with drill bits from ebay it should work for drilling pcbs.)
Also i no idea what chemicals should i use for etching and what kind of copper sheet should i use (because i heard there are many kinds of copper sheets)
A good addition to all this would be if you suggest me a program to design the layout before i embed it to the copper sheet.

Thank you.

[Ferroto]

I use EagleCAD to layout PCB's and make schematics, there's a free version available with limited functionality. As for producing the PCB's themselves you might consider a place like PCBcart which will produce PCB's based on your layout and mail them to you. Some places will even populate the board with components.

I don't know much about developing PCB's at home, I don't like working with dangerous chemicals.

[ChrisGreece52]

I use EagleCAD to layout PCB's and make schematics, there's a free version available with limited functionality. As for producing the PCB's themselves you might consider a place like PCBcart which will produce PCB's based on your layout and mail them to you. Some places will even populate the board with components.

I don't know much about developing PCB's at home, I don't like working with dangerous chemicals.

Thanks I will order one ready maybe

[ee851]

Hi Chris,

I use EAGLECAD too - the price is right.    I am sticking w/ version 5.12.0 as version 6.xx is supposedly buggy.     Suggest you view the video called   PCB Etching Bath with Heater and Agitation at http://www.pcbheaven.com/projectpages/
It shows how it is done.       Lots of other cool electronic projects on that website too.

[notsob]

Due to an avalanche of  attacks on the site by 'hacker' type activity, PCBHeaven's  forum has been shut down

[nctnico]

A few years ago I got a second hand spray etching machine. I use Ferric Chloride as an etchant. It works like a charm although you should keep it in a shed because Ferric Chloride stains cannot be removed and it is rather corrosive to metals. The plus side of using Ferric Chloride is that it can be re-activated by adding Hydrochloric acid which can be bought at any grocery store or pharmacy. So you don't end up with cans of worn out etchant.

Here is a website (in Dutch) but the pictures speak for themselves:
http://www.electronics.gompy.net/etsbak/index.html

With this machine it takes about 2 or 3 minutes to etch a PCB. Before that I used to have an immersion etching machine but that needed 20 minutes to etch a board. Foam etching is also a good method but it only works with Ferric Chloride intended for foam etching (thus without anti-foaming agents).

[ChrisGreece52]

Thank you all i think that the ferric chloride is the best way to etch a PCB at home...... but how can i find it?

[svofski]

Ferric Chloride should be available in electronics shops, expensive for small quantities (but rather conveniently packaged) — or in larger quantities at chemical suppliers. Unlike many alternative etchants, in a closed flask it lasts forever, don't hurry to throw away the solution after having etched your PCB.

Laser printer+laminator is more expensive than photo resist method at first but in my experience faster to start, easier to use, you need fewer various items to get started (printer+laminator+shears+etchant) vs. (printer+translucent paper+UV exposure box+spray+dry box+resist developer+etchant), the process is less messy too. I never had any success with a clothes iron though, that's a waste of time in my opinion. Hmm for the resist method you're going to need a printer anyway. Don't buy an inkjet. Make sure you can get your money back on the laser printer purchase too, some of the newer ones are no good for PCB making due to poor tolerances in the mechanics, they're fine for office but for PCB you need some precision.

[poorchava]

I don't agree on toner transfer method having higher setup costs than photomask method. Used laser printer you can buy for $40, and laser printer is very useful/efficient for everyday use too (using old LaserJet 4000 myself - 12k pages for $15 toner refill). Cheap chinese laminator can be had new from supermarket for $7 or so (that's how much I pad for mine).

For UV method you need exposure box, which can be quite expensive to build. Actually only way to get cost comparable to toner transfer is to get a miniature sun tanning gizmo. They typically have 4 UV tubes inside. If you want to go LED way you need to pay waaaay more. On top of that you need a developer, which is not necessarily cheap. UV-sensitive laminate is more expensive than normal one (or you have to buy UV-sensitive spray paint which adds cost too). You can use dry film (i.e. DuPont) but again: this adds cost and requires a laminator too.


I would also advise against Ferric Chloride etchant. It underetches quite easily and it leaves terrible brown stains on pretty much everything. It is also opaque so it's hard to see etching progress without taking the board out from etchant. Sodium Persulfate is far better than chloride. It's translucent (transparent at first, turning blue when saturated with copper). It's kind of an industry standard to use that. Other option would be hydrochloric acid + hydrogen peroxide, but it needs to be used in well-ventilated area as it releases chlorine gas.

[Niklas]

I have used copper laminates precoated with photo resist sensitive to UV light. The pattern was printed onto a transparent plastic sheet using a laser printer. Make sure that the plastic sheets are made for laser printers as some sheets are just made for ink jet printers and will melt inside your laser printer.

A cheap IKEA style photo frame, consisting of a tree fibre backing, a glass front and some metal clips to hold it togeter, was used to keep the patterned plastic sheet and the copper laminate in place during the UV light exposure. A sun tanning lamp or something similar can be used and the exposure time is something between 1 and 4 minutes depending on the photo resist. Protect your eyes and go to another room during the exposure.

Developing the photo resist with sodium hydroxide (NaOH), commonly used to clean out water pipes, about a tablespoon dissolved in 1 liter of water. The exact amount has to be tested as different suppliers of precoated laminates has different thickness of the coating. The laminates I used took about a minute to develop and the UV exposed areas went clean and the pattern was dark red with a hint of brown. Use water to rinse of residues of the sodium hydroxide as it will neutralize the etching agent.

If you can not get hold of etching powder, then use a mixture of 1 liter hot water (hot to the hand, but not boiling), 1 dl of hydrogen cloric acid (HCl) and 1 dl of Hydrogen peroxide 30%. Caution! Make sure to mix them in that order! The acid will mix better if it is poured into the water and the risk of splashes is less. The active etching agent is the hydrogen peroxide. Do the etching outdoors as the reaction will produce gases not so nice to breath in. The etching solution will also cause stains if spilled onto a kitchen sink made of stainless steel.

[svofski]

Re: exposure box. I used to use UV lamp that can be bought in a regular hardware store, it looks like a CFL bulb except that it's almost black. I made a makeshift reflector for it from some foil. That and two thick, ~7mm thick sheets of plexiglas to hold the sandwich of papers/pcb tight under the light. Nothing too fancy or expensive about that, made some 20 boards that way. I know some people go at great lengths building their fancy exposure boxes with UV leds and auto-off timers and that's cool but it doesn't mean that they are really necessary.

Laminator costed me slightly more than $7 however. I wouldn't advise buying a used laminator, they get dirty, the silicone rollers get deformed.

[Thor-Arne]

Hi.

I use KiCad to design my boards, it's free and can be run on different OS.

Also, take a look at this thread.

[ChrisGreece52]

Thank so much all of you!!! I would like to use the cheapest method and to be honest i did not understand everything you wrote and i am sorry for that.

So the best etchant is or isnt the Ferric Chloride?

Which is the easyest method to do it ?

Can i use a normal inject printer?

How can i use a laminator ?

Thank you.

[madires]

On top of that you need a developer, which is not necessarily cheap.

250g NaOH for around 5 or 6 Euros and you need 10g for 1l water. Lasts nearly forever :-)

[madires]

So the best etchant is or isnt the Ferric Chloride?

Each one has its pros and cons. Most DIYers I know prefer sodium persulfate since it's transparent (you see what happens) and the risk of over-etching is quite low. Fe-III-Cl is fast if you got a special foam etching machine.

Which is the easyest method to do it ?

If you done some PCBs the method you've chosen becomes easy :-) Don't expect the first PCBs to be perfect.

Can i use a normal inject printer?

Just for the photo resist method and the inkjet has to print nice dark black lines and areas. You might need to experiment with ink saver mode and different transparent papers.

How can i use a laminator ?

It's used for the toner transfer method to transfer the toner to the PCB. It's easier than using an iron (the one for ironing clothes).

PS: If you drill holes I recommend a small machine with 20000rpm or more, a drill rig and special PCB drill bits. The cheap drill bits don't last long and break easily. I like the spear drill bits.

[nctnico]

On top of that you need a developer, which is not necessarily cheap.

250g NaOH for around 5 or 6 Euros and you need 10g for 1l water. Lasts nearly forever :-)

In my experience mixing developer is not easy and the temperature is also very critical. I buy pre-made developer and keep the developer and the PCB material at room temperature. You only need a little bit to develop a PCB so the pre made stuff also lasts a long time.

[madires]

250g NaOH for around 5 or 6 Euros and you need 10g for 1l water. Lasts nearly forever :-)

In my experience mixing developer is not easy and the temperature is also very critical. I buy pre-made developer and keep the developer and the PCB material at room temperature. You only need a little bit to develop a PCB so the pre made stuff also lasts a long time.

Really? For years I simply take a HDPE bottle, fill in water, add the developer and give it some time to dissolve. The bottle for the NaOH pellets has to be airtight because NaOH is hygroscopic. And the reactivity of the caustic soda (the solution of NaOH in H2O) is decreased by oxygen over time. Right, developing the PCB at room temperature takes not longer than 30s. If it's colder nothing happens at all.

[ChrisGreece52]

So the best etchant is or isnt the Ferric Chloride?

Each one has its pros and cons. Most DIYers I know prefer sodium persulfate since it's transparent (you see what happens) and the risk of over-etching is quite low. Fe-III-Cl is fast if you got a special foam etching machine.

Which is the easyest method to do it ?

If you done some PCBs the method you've chosen becomes easy :-) Don't expect the first PCBs to be perfect.

Can i use a normal inject printer?

Just for the photo resist method and the inkjet has to print nice dark black lines and areas. You might need to experiment with ink saver mode and different transparent papers.

How can i use a laminator ?

It's used for the toner transfer method to transfer the toner to the PCB. It's easier than using an iron (the one for ironing clothes).

PS: If you drill holes I recommend a small machine with 20000rpm or more, a drill rig and special PCB drill bits. The cheap drill bits don't last long and break easily. I like the spear drill bits.

First of all thank you.
So i came to a conclusion
sodium persulfate for best etchant
inject printer with black thick lines
Iron
A lot of experimenting

Questions. Is sodium persulfate as cheap as the ferric chloride?
What do you mean by transparent paper for inject printers (i thought that these came only for laser printers)
If i get a motor like this http://www.ebay.com/itm/12V-Small-PCB-Drill-Press-Drilling-With-0-8mm-Drill-Diameter-28mm-Motor-Diameter-/290717399541?pt=LH_DefaultDomain_0&hash=item43b01b79f5 But with nice quality tips for drilling the holes on my pcb?
And Can i use copper sheets like thosehttp://www.ebay.com/itm/NEW-Copper-Sheet-Metal-4-x4-022-16oz-24-gauge-Arts-Crafts-Jewelry-Hobbies-/330853853104?pt=LH_DefaultDomain_0&hash=item4d086d27b0] [url]http://www.ebay.com/itm/NEW-Copper-Sheet-Metal-4-x4-022-16oz-24-gauge-Arts-Crafts-Jewelry-Hobbies-/330853853104?pt=LH_DefaultDomain_0&hash=item4d086d27b0[/url] to embed my design on them ?

Thank you.

[svofski]

Persulfate does not last, basicaly you have to mix a new one every time. And it produces a lot of cavitation which is not a problem with photoresist, but it easily removes toner resist.

It's really easy to use ferric chloride. Find a flat plastic bottle, like from gin or something, cut the top from it. It will contain the etchant during the etching. Hang the board inside of it vertically on a thread and a pencil (or just throw it in). Place the flat bottle in a larger can, like a plastic jar from some paint, filled with freshly boiled water. The water bath will keep the temperature of etchant high and vertical position will make it easy for the etch products to precipitate down. Usually it takes ~10 minutes to etch a board like this, single or double sided.

As for the dirty stuff: use latex gloves from the pharmacy. Do it away from where you eat, lay some newspapers on the floor, have lots of running water ready. It really helps to have a funnel to drain the solution back into a bottle where you'll keep it and some glass sticks for preparing the solution. Glass sticks are easy to clean. Some throwaway plastic tweezers to pick the board from the tank, although if you're using gloves there's no problem using fingers. Fresh spills on ceramic tiles and the such can be cleaned with just water and a sponge, just don't let them stay for more than a few seconds.

[svofski]

ah, also — NaOH is cheap but it's very sensitive to concentration and temperature. A little bit less and nothing happens, a little bit more or heaven forbid a nondissolved grain falls on a board and you have to start from the beginning. A specialized developer is only expensive if you buy it in a specialized place. If you buy sodium metasilicate from a chemical supplier it's cheap.

[ChrisGreece52]

Thank you.
so bottom line what would you suggest to me NaOH which you can get the consetration right easilly or ferric chloride?

[baljemmett]

inject printer with black thick lines
Iron

You don't need the iron if you're using photoresist instead of toner transfer, and you can't use toner transfer with an inkjet printer, so make sure you've got which method you're using straight in your head before you start buying equipment!

[nctnico]

One more thing about Ferric Chloride: when you buy it it is usually supplied as dry 'balls' in a bag. You'll need to add water to make etchant. It is extremely important that you use distilled water (for a car battery). Water from the tap contains too many polutants which will causes flocking of the Ferric Chloride.

[madires]

Persulfate does not last, basicaly you have to mix a new one every time. And it produces a lot of cavitation which is not a problem with photoresist, but it easily removes toner resist.

Usually it lasts about a year for me (etching machine). Fe-III-Cl etches even at room temperature (foam etching around 45°C), sodium persulfate works best around 40-45°C.

[ChrisGreece52]

Thanks guys but i cant store all these info
But just suggest the best etching method for a beginner the most cheap to if this is possible.

Thank you and i am sorry but i am getting more confused with all these.
If you want me to understand please explain all the technique's for etching (or the 3 most popular if not all) the products each one uses and the process and tools it takes to etch a board.