Tell me more about sharpies and etching...

[JimRayden]

I'm looking into etching a few boards. Do any permanent marker work or is it just the special feature of all products of a company called Sharpie? 

So basically I can do all the etching with a random permanent marker, no need of printing or ironing, right? And I don't have to buy the super-expensive PCB-pen at the local electronics store?

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Jimbo

[Gringo]

So basically I can do all the etching with a random permanent marker, no need of printing or ironing, right? And I don't have to buy the super-expensive PCB-pen at the local electronics store?

Exactly.

[Paul Marossy]

The Sharpie pen in those RS kits is just a regular old Sharpie pen, nothing special at all. If you use a Sharpie pen, for best results, make sure it goes on thick and makes sure it etches fast!

[Joe Kramer]

Hey Jim,

Plain black Sharpies work fine, and, as Paul says, make sure it goes on thick: you shouldn't be able to see copper through the ink.  Also, because Sharpie ink is basically lacquer, it needs to dry for as long as possible for best etch resistance.  The best thing to do is set the board in the sun, where the UV rays can cure and harden it.  Short of that, let it dry for at  least 48 hours.

Joe

[Mark F]

Hey Jim,

Plain black Sharpies work fine, and, as Paul says, make sure it goes on thick: you shouldn't be able to see copper through the ink.  Also, because Sharpie ink is basically lacquer, it needs to dry for as long as possible for best etch resistance.  The best thing to do is set the board in the sun, where the UV rays can cure and harden it.  Short of that, let it dry for at  least 48 hours.

Joe

SUN!? I live in Buffalo New York! There is no sun for the next 4 months!  Sorry!    I couldn't resist. It's really not that bad here.

[nelson]

Not to discourage you or anything jim. But when I first tried etching I used sharpie. It was a disaster, for anything other than really simple boards (LPB2) its time consuming, prone to human error and if you arent careful to let it cure properly and have hot fast etchant, doesnt work.

I swear by press n peel blue. I am so good at it now I can get less than 1mm trace circuit boards perfect.
The secret is just leaving the iron on top of the whole VERY clean sandwich for 5 mins. Then ironing firmly for 2 mins making sure to get all the edges. I get a perfect transfer 95% of the time, if not the sharpie comes out and I correct the broken "future traces".

imo, this is the only efficient and sensible use of a sharpie in making boards.

[The Tone God]

I don't think sharpies are that great for doing whole boards. About all they are good for is touch ups. The reasons sharpies are good for etching is that they are fairly inert/resistive to the chemicals involved in etching. There are other markers that can fit the bill but sharpies or sharpie-like markers are easily available.

Some of the better quality resist markers leave a thicker ink footprint then sharpies so they do a better job for etching but the good ones are hard to get and expensive. I would still only use them for touch ups anyways.

Andrew

[JimRayden]

Hmm, looks like risky business unless I use the expensive marker.

I'll try the printing method if I can track down an inkjet somewhere.

What's the difference between an usual film sheet and the famous PnP?

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Jimbo

[1978]

You don't need an inkjet--just go to Kinko's, or use your local Korean grocer's Xerox.  The toner in [most all*] photocopiers will work with PnP.  Plus, you can cut out just the right size of PnP for your PCB, and don't waste as much setting up printer margins, etc.  I did my first dozen boards with sharpies and I laugh when I look at them now.  There's just no way to get those thin traces by hand--they work just fine, but they're huge.  I haven't used anything other than Press n Peel, but I still have about 50 projects worth of sheets left.

*I say "most all" because my local Korean grocer's Xerox machine suddenly stopped giving me usable PnP transfers. 

[JimRayden]

Well, I don't have any thin traces to draw, it's a quite simple distortion circuit. I do have some film sheets that I could try out though. What's the difference between PnP and film?

------------------

http://www.elfa.se/elfa-bin/dyndok.pl?lang=en&vat=0&dok=1989.htm
How well would this work compared to a common permanent marker?

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Jimbo

[GFR]

I often use a sharpie with good results (well it looks ugly, but works ok).

I don't like to do the solder pads with the sharpie, I use letraset pads

http://www.letraset.com.br/eletroset.html



And then I use the sharpie to connect the pads. If you're using only discrete componentes you may try to draw the pads with the sharpie, but if you're using ICs the letraset pads are a MUST. BTW the letraset pads come at the right spacing for the IC pins, that saves a lot of trouble.

Also, if I'm using a sharpie or even letraset thin traces, I NEVER even try to pass a trace between two IC pins.

I never waited 48 hours for the sharpie to dry. Maybe 15 minutes

The PnP method otoh looks so much better ("pro"), and you can do much more complex things.

[fixr1984]

Where can you get the pnp paper? Is it just a paper you buy and print on then just use an iron to seal it to the pcb?

[RLBJR65]

My first 2 dozen or so projects were hand drawn with a Sharpie and dry erase transfers from Rat Shack.
I did GGG's Marshall Blues Breaker and Orange Squeezer also Kent Stevenson's layout for John Hollis Crash Sync those were a PITA but smaller stuff like an FF, LPB, Electra dist. etc. etc. were pretty easy. I just drew them out let it dry then touched it up and let it dry again. Worked well everytime unless I got in a rush and tried to etch it to soon, then you get pits etc. I had much more problems with the dry transfers than with the Sharpie. Remember to keep some Qtips and rubbing alcohol handy for cleaning up goofs , if your carefull that will keep you from having to redraw the whole board.

I don't do it anymore, usually small stuff goes on vero or perf and bigger stuff I use Laserjet transfers printed on almost any slick paper. BTW left over sticker paper works great I got mine from a large 6' X 3' side decal for a cargo van, so if you have any graphic shops in your area make friends! They just throw the stuff away anyhow. Photo paper works great but can be expensive, heck I saw a web page where the guy just cut a cover of off a magazine printed right over whatever was on it and ironed away, seemed to work well for him but I never tried it.

If needed to however I would not hesitate to use a Sharpie again. As many have already said, you definitely need one around for touch ups.

Richard

[Paul Marossy]

What I actually do is print out my PCB layout on plain paper using a LaserJet printer. Then I iron on the image onto the blank PCB and get as much of the toner to release as possible. Then I go over that with a Sharpie, good and thick. That gives me a pattern to use and pretty much eliminates the human error part. This is how I have done every PCB that I have ever made. I haven't really had a "failure" yet using this method. YMMV. 

[JimRayden]

If you use a Sharpie pen, for best results, make sure it goes on thick and makes sure it etches fast!

I have the acid in dry form. To etch faster, I just make a denser compound, right?

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Jimbo

[1978]

Heat will help it go quicker, too.  I've tried gently warming the solution in a double boiler-type thing.  Just to get it warm, not necessarily hot.  I've also tried putting a 100 watt clip lamp right over the solution.  But I think what works best is to agitate the hell out of the container --not quick agitation, just steady, consistent motion to keep the liquid moving over the board

I just use the Radio Shack FeCl, but the bottle doesn't give the percentage of the solution.  I'm trying to think back to chem lab--and I'm not sure that more solution/reagent will necessarily make it go quicker.  You'll certainly have to have enough acid so that there are enough molecules to bond with the copper you want removed.  But really, I believe "heat" in any of the above forms is the surest (only?) way to speed up a chemical process.  (of course maybe my chem teachers were just keeping things some of the secrets of the universe safe from us).

a serious question i wrestle with:  does anybody have preference for copper side up or down in the tray?

Where can you get the pnp paper? Is it just a paper you buy and print on then just use an iron to seal it to the pcb?

I got mine from www.techniks.com, but smallbear and others carry it too.

[fixr1984]

What I actually do is print out my PCB layout on plain paper using a LaserJet printer. Then I iron on the image onto the blank PCB and get as much of the toner to release as possible. Then I go over that with a Sharpie, good and thick. That gives me a pattern to use and pretty much eliminates the human error part. This is how I have done every PCB that I have ever made. I haven't really had a "failure" yet using this method. YMMV. 

I tried this last night and it barely shows up on the board. I tried both photo paper and regular paper. Guess it means getting the pnp blue from Smallbear or something.

[Paul Marossy]

I tried this last night and it barely shows up on the board.

You have to have the iron really hot and use a lot of pressure to get it to come off onto the PCB. I have done it dozens of times now, though, so I guess I have got it down to a science. It's certainly far from perfect... 

[fixr1984]

How dark does it show up? I had the iron to max and held it on there for almost ten minutes and you can faintly see the outline starting to appear.

[Paul Marossy]

Usually, not real dark, but enough to make the layout clear. It only gives you an idea of where to draw on the PCB with the Sharpie. Press N Peel is really the best thing to use, especially if you want to do mutilples of the same board. I just do one offs at this point, so I just do the Sharpie thing.