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CodeMonk 03-12-2011 01:58 PM

CodeMonks Buillding your own PCB tutorial
 
Making your own PCBs tutorial

How do you make your own circuit boards?
Its a lot easier than you think.
But there are some precautions you need to take.

I'm going to show you the low budget way to do it.
There are several ways to do it, but I like the low budget way, so that's what
I am going to show you.


First off, stuff you need:
Computer
Program for designing circuit layouts
Laser printer ( Ink-jet will not work (See Note #1 Below ) )
Photo paper made for laser
Copper blanks
Etchant
Drill Bits (Recommended sizes. YMMV).
....For component holes: 0.035 - 0.038 (#60 - #65)
....For wire holes: 0.040 - 0.045 (#54 - #56) - I use 22 gauge wire.
Drill or Drill press (I paid $40 for my drill press)
Iron (the type you use for clothes)
Plastic tub
Safety glasses
Rubber gloves
#0000 steel wool and/or 400 grit abrasive paper. Scotchbrite pads can be used as well.
Small air pump (not necessary, but speeds the process up like 400%)
Plastic or glass container
LOTS of water standing by (For safety reasons)


=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=
Note #1 : While ink from an ink jet printer works just fine and dandy on paper or other medium, when dipped in a liquid (such as a liquid etchant), the ink will run, making it useless for etching.
Laser Toner however is plastic or wax based and will remain "dry" and will not run if exposed to a liquid.
Laser Toner can be removed with acetone though if needed.

=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=


OK, first up, VERY IMPORTANT:
You will be using chemicals, some of which are hazardous...

For disposal, contact your local waste management facility

MSDS stands for Material Safety Data Sheet

Sodium PerSulphate MSDS
http://www.sciencelab.com/msds.php?msdsId=9927601

Muratic Acid MSDS
http://www.brown.edu/Departments/Vi...uriaticacid.pdf

Ferric Cholride MSDS
http://www.sciencelab.com/msds.php?msdsId=9924033

http://wiki.answers.com/Q/How_shoul...f_muriatic_acid



Up next, the Layout.
You can design you own or use one of the many available. If a DIY pedal exists,
someone has likely already done a layout for it.

For layout software, I prefer DIY Layout Creator (http://code.google.com/p/diy-layout-creator/)
You can create a layout in 30 minutes or less. It can also take days or weeks.

Laser printer. Ink-jet printers will not do. Laser toner is plastic based which you will soon see is critical to this method working.

Copper blanks you should be able to get at any electronic hobby store.
Avoid the double sided ones unless you really need them.
Radioshack even sells them. You can also find them at Smallbear
(http://www.smallbearelec.com/Catego...tart=9&total=23)

Etchant. Several options here. Sodium Persulfate Powder, Ferric chloride, Or a combination of Muratic Acid and Hydrogen Peroxide (Which is what I use).
With the Muratic Acid and Hydrogen Peroxide you can have about 4 gallons of etchant for less than $20. The others are $10 or more per quart)
But Muratic Acid is very caustic (Hence the "LOTS of water standing by" bit above).
Ferric chloride you can get at most electronic hobby stores (even radioshack)
Muratic Acid you can get at most large chain hardware stores or pool cleaning supply stores.
Hydrogen Peroxide can be found at any drug store/pharmacy.

Sodium Persulfate Powder, I have never used so I can't comment on that.
Ferric chloride:
Downsides, while only about $10 a quart, it etches a little slow and its a dark red so you can't easily check the progress of the etching. Also, anything it touches it stains. Get it on your hand for even a few seconds, it stains.
The stain will be there for awhile.
Upside: less caustic to skin

Muratic Acid solution:
Downsides, very caustic. Will burn your skin. That why I keep lots of water around and wear the gloves.
Upside, costs much less than Ferric Chloride.

The iron, anything works. I paid $4 for mine at Walmart.

Plastic tub. I personally use one that previously held a gallon of ice cream.
This is for after you apply the layout from the photo paper to the copper.

Safety glasses. We may be working with some nasty chemicals. A full faced safety shield is better.

Rubber gloves. I prefer Nitrile gloves as they stand up much better to acetone than latex does. Cost is about the same.

Plastic or glass container for doing the etching.

Long sleeve shirts should be worn when handling the etchant.

CodeMonk 03-12-2011 01:59 PM

Ok, lets get started shall we?

Some equipment and safety info first:

Here is where the "LOTS of water standing by" is for.
2 - 5 gallon buckets. Time to change these soon.
We are going to be using the Muratic Acid and Hydrogen Peroxide solution for etching. Its a caustic solution.
Muratic Acid is used to clean pools and grease stains and such from concrete driveways.
If I get any on me, I dip my hands in these buckets ASAP. It can burn if not taken care of quickly.



Nitrile gloves.
You can use latex or vinyl but I find that nitrile is more durable with acetone and the etchant. Although some brands can tear
easily when you put them on.




Here is what happened after I left an open container of the solution overnight in my garage.
Thats my drill press. It was all shiney before.
So always seal any solution after use in a plastic or glass container (No metal containers or lids).


CodeMonk 03-12-2011 02:00 PM

Here is what we are going to be etching a PCB for.
Since this is just for a test, no need to design for the
transformer.




Ok, so now we need to design the circuit layout.
Using DIY Layout Creator (http://code.google.com/p/diy-layout-creator/)
I created the layout. I made it fairly open so you can see the circuit traces easily.
Generally I design boards much more compact than this.
You are going to need the layout so you know where all the parts go.
I also left out the switch labeled "S1". I personally like the sound with the switch bypassed.
I think the harmonics are sweeter.
Also to show that its sometimes relatively easy to mod a circuit.
R1 is a resistor
C1 - C5 are capacitors
D1 - D3 are diodes
Q1 is a transistor
When assembling take care the orientation of Q1
P41 is the volume control

You can find all these at Radioshack even.

Anyway, I am hoping anyone interested in this knows something about the different components
and how to solder and hopefully able to read schematics.
If you lack any of this knowledge, might I suggest the following sites:


http://www.geofex.com/Article_Folders/how_to_solder.htm
http://artsites.ucsc.edu/EMS/music/.../ReadSchem.html

Diy Layout Creator has an option for saving the layout as a GIF file (listed under the "File" button), "Render Image"




Ok so we created a layout. Now to get the circuit itself from this design
Diy Layout Creator has an option for this as well (listed under the "File" button), "Render PNP"

The text I added. Take care that its mirrored. Any text you want on a circuit board has to
be done mirrored.
For the image properties, set Pixels Per Inch at 200.
And that gives us this:

EDIT:
With updates the DIY Layout Creator, Pixels Per Inch should be set at 300 for printing.
Your image application should allow you to set this value.




Now, using a laser printer, print out the circuit on PHOTO PAPER MADE FOR LASER.
I usually print out extra circuits because my laser printer is kind of a POS.
I can choose the best image.

EDIT:
Recently I have been using glossly presentation paper.
It's about 1/3 the price of photo paper and IME, produces a better result.





Next you cut out your copper a little bit bigger than your design.
Then using the 400 grit abrasive paper to clean the copper. Oxidation is very likely on it and needs to be cleaned off or the circuit design will not stick to the copper properly. Sand in a circular motion
until it looks clean.
Then clean the board off with Acetone.
Wear gloves and safety glasses while doing this.




Now we get ready to apply the design to the copper board.
Notice how I don't let my bare fingers touch the board.




Now we lay the circuit FACE DOWN...


CodeMonk 03-12-2011 02:01 PM

And we begin using the iron.
Set the iron on the hottest setting (usually Cotton).
Apply light to medium pressure, moving in a circular pattern.
For a board this size, 45 seconds to 1 minute should be fine.
It also helps if you hold down a corner of the photo paper with something (NOT YOUR FINGERS!),
until the circuit pattern starts to stick to the copper.
This part can be a bit tricky and may take some practice. it took me several tries to get it right
the first few times I made my own boards.
For larger boards, it will take more time. Also for larger boards, I generally use a toaster oven I use
for baking pedal enclosures after I paint them. What I do is heat up the board first. About 150 - 200 degrees should be fine.
This only applies to larger boards. For small boards its not necessary.
If you use a toaster oven for either purpose, DO NOT USE IT FOR FOOD EVER AGAIN!




We now have the circuit transferred to the copper, time to give it a bath.
I use warm soapy water. What we want to do is soften the paper so it comes of easily, leaving the trace on the board.



Now let it soak for 10 - 20 minutes.
After we remove the board from its bath.
You can just use your fingers and a toothbrush to remove the wet paper.
And here is what we get from that:




Ready for etching!
Next step...
Now what I have done here is taken some strips and little squares of plexiglass to create something
to hold the PCB at the proper height. We want the board raised up enough so that it is just barely
in the solution.
The mixture of the solution, well, ask ten people, you will get ten different answers.
As for me, I use a mixture of roughly 3/2 - Muratic Acid/Hydrogen Peroxide.
Pour just enough in the barely cover the board.

Muratic Acid and the Hydrogen Peroxide.
The little cup on top of the peroxide I use to measure out the chemicals.
measure carefully.




Here I use a small air pump you can get at anyplace that sells fish for $5 or so.
Buy it at an electronics supply store and its around $10. But you also get the hose and something
to attach it to. What you want for this to do is create multiple small bubbles underneath the board.
This greatly speeds up the etching versus just letting the board sit it the solution.
Another option is to continually rock you etching tank back and forth.
Trust me the air pump is the way to go by far.
What you want if using the air pump is something non-metallic to plug the hose into with multiple
holes in it that blow air bubbles at the board. I use a hard piece of rubber. A real bitch to drill holes
in but I have a big piece that 1/2 inch thick and about 5 x 5 feet.

Now here we are etching. Notice the bubbles. And the shield.




Now we have our etched board (ok, I took it out to soon and left a tiny piece of copper there.
Not to worry in this case. Its away from the circuit and will likely be trimmed anyway.




Now you see why the text was printed in reverse :)



Now we start drilling the holes needed for the components and wires:
Note #2: Before you start drilling make sure that the little holes the components will go through are clear of the toner. It helps to keep the drill bit from drifting or wobbling.
Those drill bits are very thin and bend easily. And fiberglass tends to dull the drill bits a bit. Carbide bits are an option but they cost about $6 each. regular ones, you can get like 10 of them for a few bucks.
(Sorry, a little blurry)
NOTE: make sure you wear eye protection and some sort of mask to prevent inhaling fiberglass dust
(Another blurry picture)




After we drill all the holes (see list for drill sizes), we need to debur the holes and remove the laser toner.
Use the 400 grit paper to remove the burs and Acetone to remove the laser toner

And we get....





Nice and purty

And there we go, ready to be assembled.

Any questions, problems, etc, reply in this thread.

Enjoy...and be careful.

CodeMonk 03-12-2011 02:01 PM

*Reserved4

CodeMonk 03-12-2011 02:17 PM

*Reserved5

the_white_bunny 03-12-2011 02:17 PM

im going to school for electronics and computer engineering so this is very interesting.

GS LEAD 5 03-12-2011 02:41 PM

I didnt get one thing.
You stuck the piece of copper into the muriatic acid. Wont all the copper get corroded?

CodeMonk 03-12-2011 02:43 PM

Quote:
Originally Posted by GS LEAD 5
I didnt get one thing.
You stuck the piece of copper into the muriatic acid. Wont all the copper get corroded?



The copper gets eaten away by the acid. Except the parts covered by the toner material.
So you get a nice circuit.

forsaknazrael 03-12-2011 02:43 PM

Pretty good, but it's worth mentioning that it can be difficult to get a good ratio of Muriatic acid and hydrogen peroxide. An imbalance can easily be too aggressive of an etch on the copper clad material.
EDIT: I get much better results with sodium persulfate or ferric chloride.

Additionally, I would recommend advising people to use a toothpick to make sure the holes in the etch are cleaned out, to ensure that the copper there gets eaten. It makes for an easier time drilling, IMO.
Also, I get my tiny bits at Drill Bit City.

I do like your air pump idea, though. :thumbsup:

CodeMonk 03-12-2011 02:45 PM

Quote:
Originally Posted by forsaknazrael
Pretty good, but it's worth mentioning that it can be difficult to get a good ratio of Muriatic acid and hydrogen peroxide. An imbalance can easily be too aggressive of an etch on the copper clad material.

Additionally, I would recommend advising people to use a toothpick to make sure the holes in the etch are cleaned out, to ensure that the copper there gets eaten. It makes for an easier time drilling, IMO.
Also, I get my tiny bits at Drill Bit City.

I do like your air pump idea, though. :thumbsup:



I've used 1/1, 2/3, 3/4 and a few other ratios in that range and haven't had any problems.

But little update to that post forthcming.
Edited:
Note #2: Before you start drilling make sure that the little holes the components will go through are clear of the toner. It helps to keep the drill bit from drifting or wobbling.

But good point. Guess I should have been more specific on that. I usually use an exacto blade myself.

Edit2:
I've used ferric Chloride, but didn't like the fact that it made it harder to monitor the progress, plus the acid and peroxide costs less. I'm a cheap bastard sometimes.

supersac 03-12-2011 02:47 PM

i like this ive always wanted to make my own pcb ones now i guess i have to find a place to get the chemicals from(my local stores all suck)

forsaknazrael 03-12-2011 02:47 PM

^If you live by a Radioshack, you can get Ferric Chloride. They will order anything to your local store for free.

I edited my post, too.
I'd like to try ammonium sulfate, I hear it works really well, but it's much more expensive.

Good tutorial, though. We need more DIY! :cheers:

Do you think the air pump would work well for multiple boards? I often etch 4-5 boards at a time in a bigger container.

CodeMonk 03-12-2011 02:56 PM

Quote:
Originally Posted by forsaknazrael
^If you live by a Radioshack, you can get Ferric Chloride. They will order anything to your local store for free.

I edited my post, too.
I'd like to try ammonium sulfate, I hear it works really well, but it's much more expensive.

Good tutorial, though. We need more DIY! :cheers:

Do you think the air pump would work well for multiple boards? I often etch 4-5 boards at a time in a bigger container.



As long as you have enough bubbles, should be fine. Most I have done was 3 boards at once.

I have 3 different sized containers I use for etching (two of them previously held walmart brand potato salad :) )

GS LEAD 5 03-12-2011 02:57 PM

Quote:
Originally Posted by CodeMonk
The copper gets eaten away by the acid. Except the parts covered by the toner material.
So you get a nice circuit.


But you can see a pretty big block. Is the copper thing a non metallic copper plated thing? Or a solid block?

CodeMonk 03-12-2011 03:00 PM

Quote:
Originally Posted by GS LEAD 5
But you can see a pretty big block. Is the copper thing a non metallic copper plated thing? Or a solid block?



If you mean that bit in the upper left, yeah, I just took the board out to soon.

Its a thin sheet of copper bonded to fiberglass. Epoxy and other materials besides fiberglass are also used.

If you mean at the bottom of the board, thats the manufacturer's logo. Printed on the OTHER SIDE of the PCB.

konadave 03-12-2011 04:58 PM

Good tutorial.

I've always used ferric chloride, think I'll try out the muratic + h2o2 next time. Photo paper also sounds like a good idea, I've been using transparency film.

forsaknazrael 03-12-2011 05:02 PM

^read my thoughts on Ferric Chloride versus Muriatic above.

The one upside of Muriatic is that the blue byproduct, Copper Chlorate, can also be used as etchant, it just needs more Hydrogen Peroxide. Ferric Chloride eventually becomes inert.

XgamerGt04 03-12-2011 07:49 PM

You'll want to be careful about reworking these type of boards though. As the holes are not plated through it is much easier to lift the traces when desoldering parts.

I'll have to look for the stuff we have at work that can be used to plate holes. I also like the UV method and photo resist boards much better when it comes to intricate pcb designs.

Good tutorial though, I would use a drill press anytime you drill holes on a pcb.

CodeMonk 03-13-2011 01:19 AM

For the first year or so I was making boards, I used a hand held power drill.
It was a real pain in the ass. Fortunately, I was mostly only building fuzz, OD, occasional compressor, and other simple circuits.
First time I built a delay, drilling the holes made my arm sore as hell. Plus had a lot of holes drilled at angles etc.

I'd like to find out about through hole plating as some circuits I have designed require double-sided boards.

And I agree, the photo method is far superior to this one when it comes to intricate traces.

Also, I prefer the muratic method because its much easier to see the etching process cause the solution is clearer. The solution also turns green/blueish color as the copper starts being removed.
There are upsides and downsides to any method of board etching.
One other downside I have noticed is that the muratic acid/hydrogen peroxide solution, well... you mix it up then let it sit without using it, it tends to weaken its effectiveness.
But a little added peroxide before etching usually takes care of that.
And Ferric Cholride has never burned me, although I did have orange fingers for a few days when one of my gloves broke :)

Edit:
I feel also should also point out another safety issue...
NEVER EVER PUT ANY ALUMINUM INTO THE MURATIC ACID SOLUTION. With aluminum a chemical reaction takes place and the solution will start violently boiling and will melt your plastic etching tank (If thats what you use).

Edit2:
I've been working in the electronics field off and on since 1980. There is a lot of knowledge and in some cases, long dead techniques in this old brain of mine and I really wanted to contribute some of my knowledge to this site.


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