pcb making with a sharpie

Thread Starter

pkennedy

Joined Feb 27, 2009
44
I have done a search and have been looking on the web to find out if it is possible to make traces on a pcb board with a sharpie.I know it wouldnt look as good as using software and inkjet printer but for some simple circuits it would seem to make things a little faster by just hand drawing your circuit.also I was wondering about an acid that could be purchused locally that would work for etching.I live in a rural area and dont really want to order it off the internet.any advice or help would be appreciated.
 

jpanhalt

Joined Jan 18, 2008
11,087
Sharpie have been used for making PCB, particularly in the days of ferric chloride etching. Something that applies a thicker line of paint might survive the etchants better. Various brands of paint markers are available from arts and crafts stores, such as Michaels. DecoColor (Marvy) or Brite-Mark (Dykem) are two with which I am familiar.

As for etchants, look up HCl - peroxide. Basically, a mixture of hydrochloric acid (also called as muriatic acid, obtained in pool and home renovation supply stores) and ordinary 3% hydrogen peroxide is used. Be sure to refer to specific directions that are easily found on the Internet as well as on this site.

John
 
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studiot

Joined Nov 9, 2007
4,998
Don't know what a sharpie is but you can make a very good etchant mask with either nail varnish, car body touch up paint, or typewwriter correction fluid.

All come in little bottles complete with tiny application brushes.
 

hobbyist

Joined Aug 10, 2008
892
Radio shack puts the whole kit out "PCB kit" it has the 1/8" drill bit, + a circuit board + a PCB marker pen, you can also buy them seperate, thick trace or thin trace, it comes in ir's own etching tank about 4 X 6 X 2" plastic box, as well as a small bottle of etchant, and saline solution.

Nice little kit for drawing and building PC boards.

This was back in the 80's but they probably still have this I guess..
 

SgtWookie

Joined Jul 17, 2007
22,230
Hobbyist,
Radio Shack stopped selling that kit about 5 or so years ago. Some genius decided that ferric chloride was a hazardous material, and it became too expensive to ship it to the stores.
 

studiot

Joined Nov 9, 2007
4,998
Thanks for the information about Sharpies. We don't have that brand here.

My experience with felt tip has been that it is extremely difficult to make a perfect coating without micro holes.

Etching solution easily gets through holes too small too see with the naked eye.

That is why I like a paint on laquer.
 

Wendy

Joined Mar 24, 2008
23,415
You have to figure on hand drawn PCBs that is not going to be an issue. ;) Back when I was doing it that way I was working on 5 transistors (max) circuits, with the norm being 2.
 

jpanhalt

Joined Jan 18, 2008
11,087
The paint/lacquer applicators I mentioned (DecoColor (Marvy) or Brite-Mark (Dykem)) provide a nice flow without the need to dip a brush. Both have fiber tips, but the paint flows more than the fast drying ink from a marker.

Of the two, DecoColor has a little finer tip, and I suspect it is available worldwide in craft stores. It is made in Japan (Uchida) and may go by different names. You can get a very tiny dot for touching up resists, but still not as fine as you can get with the finest tipped Sharpie.

Dykem is usually associated with industrial metal working. It also makes layout inks.

John
 

Thread Starter

pkennedy

Joined Feb 27, 2009
44
i may try some of the differant type masking types but is the best etching solution the hcl or is there something else that can be found .it seems a little potent to use but if that what it takes i guess i will use it.I have seen the etching solution on the web but would like to get some locally.as sgtwookie stated i dont think radio shack sells it and i leave in a rural area.thanks for the input
 

studiot

Joined Nov 9, 2007
4,998
If your solution is too strong it will not only cut down vertically through the copper, it will also eat sideways under the edges of the mask.
This produces a very ragged edge to the finished tracks and lands.

I would not recommend hydrochloric acid. Ferric chloride is strong enough.

It is also a good idea to agitate (stir) the bath from time to time. Commercial tanks often included a vibrator.
 
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studiot

Joined Nov 9, 2007
4,998
Hopefully some US contributors will have a better idea.

It comes as greeny brown crystals in a hermetically sealed pack. You dissolve some in water to make up an etchant solution.

It has a tendency to absorb mositure from the air and forms a gooey mess so don't buy too much and re seal what's left.

It is mildly poisonous, and of course corrosive, to take care. Use rubber gloves. Hoever unlike hydrochloric acid it does not produce toxic fumes. Not the best of smells though, so ensure adequate ventilation.

Always make sure the copper board is degreased before starting, as grease traces also act as a mask. Some people lightly polish the copper with Brillo first. Preparation is everything, as with most activities in this world.
 

jpanhalt

Joined Jan 18, 2008
11,087
I was wondering about an acid that could be purchused locally that would work for etching.I live in a rural area and dont really want to order it off the internet.any advice or help would be appreciated.
That is the only reason I recommended the HCl/peroxide method. I still prefer ferric chloride and as a close second, cupric chloride. Neither is available in Cleveland, Ohio, except in 600# minimums. I don't know about your particular rural area.

Although some etchants are faster than others, undercutting is the major difference between methods that affects final quality. However, since you are contemplating hand drawing the resist pattern, I don't think you will notice any difference in appearance with the different etchants.

One additional caveat about etchants: I have found HCl/peroxide to be more aggressive toward the photoresist that I use than either ferric or cupric chloride. That may or may not apply to the various paints and inks you are thinking of using. I believe it is something you should test before etching an important board.

John
 

ELECTRONERD

Joined May 26, 2009
1,147
Yeah, RadioShack has kind of lost it. They don't sell the individual parts and even a lot of the kits that they used to. They are more into the cell phones now and things like that...bummer....
 
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