Tell me more about sharpies and etching...

[KMS]

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.

I'd say something is wrong with your iron or your print was from an ink jet printer.  Only the toner from a Laser Jet printer will work.


I have a candy thermometer.  After I have made a nice dark copy on my PnP blue from KINKO'S I put the candy thermometer on the iron and wait until it reads between 300 F and 310 F.  Then put the iron on the PnP blue setting on the PCB. Nothing between the iron and the PnP blue.  It take three minutes moving the iron around a lot and in the end using the tip of the iron to push each trace down.  Quench in cold water and it's done.  

[KMS]

Also about the sharpie.............

At 70 degrees F the sharpie will be as dry as it can be in about 5 min.     I have used it for writing my name on my boards and touch up.   I have had some etches go as long as an hour with the sharpie drying for only 5 min and holding 99% of what I put it on and only a small amount around the fringe edges came off. The trick is a clean piece of copper and a thick coating of sharpie.  Drying time and etching time are not really factors to worry about.

[Paul Marossy]

The trick is a clean piece of copper and a thick coating of sharpie.  Drying time and etching time are not really factors to worry about.

Clean copper, yes. Thick coating of Sharpie, yes. Etching time not really a factor to worry about? I don't completely agree with that because of my experiences, but generally 5-10 minutes will give you good results. The last RadioShack PCB kit that I bought was horrible - it took me 30 minutes to get the board to etch completely. The results weren't too bad, but it really sucks compared to the kits I have bought in the past, which is maybe 5 in the last 5 years. 

[KMS]

I just finished etching a new PCB, with a lot of sharpie touch up (I forgot to make a "dark" copy on my PnP blue at KINKO'S today).  This has been my worst PCB etch yet, and it will work just fine.  I have looked it over under the Magnify lens and all is well, thanks to the sharpie.  I used 3rd time FeCl and the etch took about an hour with minimal agitation, a lot of smoke breaks etc.

I put it in the FeCl within minutes of using the sharpie.  No specified dry time, maybe one minute.

I do want to add that the PCB was one that I drew on Microsoft Word using the "Drawing" tool bar.  It is very rewarding to make your own PCB design and just about as easy as using the sharpie.

[KMS]

The trick is a clean piece of copper and a thick coating of sharpie.  Drying time and etching time are not really factors to worry about.

Clean copper, yes. Thick coating of Sharpie, yes. Etching time not really a factor to worry about? I don't completely agree with that because of my experiences, but generally 5-10 minutes will give you good results. The last RadioShack PCB kit that I bought was horrible - it took me 30 minutes to get the board to etch completely. The results weren't too bad, but it really sucks compared to the kits I have bought in the past, which is maybe 5 in the last 5 years. 

I would not base all your boards on that one bad experience.  Maybe you had a bad sharpie.  I use sharpies at work everyday and not all of them are good.  Some have set around a long time on the shelf and are not worth a damn.  Also, Radio Shack copper clad is not any good in my book.  I had a bad experience with their stuff too and I no longer buy form them.  I get my boards from Gateway Electronics in St. Louis and I pay about $3 for 6" x 12" board and the copper is high quality #1 copper (not an an alloy like Radio Shack has).

So if you get the board from Radio Shack, then your method should work better.

[robbiemcm]

We don't have a laser printer at home, but my dad has some at work and photocopiers aswell. But I suppose it's better to use the normal laser printer just for this? Also.. I'm looking at purchasing some of these PnP sheets maybe while I'm here in England. So do any British people know a good place I'd be able to get them that's quite close to Oxford and hopefully for a good price, and maybe they'd be able to provide me with an insight as to what that price may be close to.

Thanks alot,
Robbie.

[Mark Hammer]

Okay, about Sharpies...

"Sharpie" is used like "Kleenex" or "Aspirin" or "Walkman".  At this point, the reference to the brand is largely historical amd not a requirement.  ANY, I repeat ANY waterproof marker will work.  Back in the day when circuits were simple and discrete, and both pads and traces were on the chunky side, Sharpies were suitable.  These days, you need a fine tip to be able to negotiate the twists and turns of layouts that will fit in the spaces afforded by 1590B boxes.

I've pretty much stopped using pens since getting an old laser printer, but before I had it, I used Staedtler Lumocolor pens.  They are reasonably priced, handle nicely, and have fine tips.  The method I took to using was to have two different coloured pens, like red and blue or red and black.  There is no real magic to the colour chosen.  Rather, I would draw the layout in one colour, and with a change of colour I could easily keep track of what I had and hadn't touched up. 

Does it need to dry, as suggested above?  Personally, I don't think so.  If anything, plunk the board in the etchant as soon as the ink doesn't smudge.  This guy says you have far more to fear from copper that has lapsed from gleaming to dull than you do from ink that hasn't cured perfectly.  YMMV, but that's my take.

I strongly recommend getting some Lumocolors anyways, even if you do make the switch to PnP, glossy paper, etc.  Until you get the hang of ironing (sometimes even after) you can run into imperfections in what gets transferred to copper.  You can use the Lumocolor to touch up the pattern on the copper board.  I've been at it for a while, and *I* still do it.  You'll do it too.

Although you can do some very nice boards with simple penwork, try to make the changeover to iron-on transfer if you can, simply because it is REALLY hard to keep finger juice off the copper when drawing, and finger juice impairs etching.

If you cut and paste a bunch of patterns (don't forget to include duplicates) onto a letter-sized sheet and bring it to a photocopy place for transfer onto a sheet of glossy photopaper, I would be VERY surprised if it would cost you more than a dollar.  You can fit 8-10 patterns big enough for a 1590BB on a sheet easily.  Paying 10-15 cents per pattern is a pretty sweet deal.

[MR COFFEE]

Jim,

In case you didn't catch this, you had referred to a inkjet - it *has* to be a laser printer or photocopy machine.

The toner is the resist - it's a plastic... ink isn't.

Warm etchant is critical to fast etching times, as opposed to hours and pinholes. 140 F, celsius - oh I'm too lazy this late and this many beers 

If you live somewhere where you can't get PnP Blue, look up Tom Gootee's pcb method using more readily available materials. Not quite as good as PnP Blue, but it works.

Here's a link. Easier and better and faster than sharpie.

http://www.fullnet.com/u/tomg/gooteepc.htm