Sharpie to protect against oxidation?

[The Rocket From The Tombs]

Would applying a thick layer of sharpie over copper traces do anything to protect against oxidation? If it can keep acid from getting a hold of the traces I'd imagine it could keep air out, too  .

[mremic01]

I just solder over the traces, then run a hobby knife between them to get rid of the flux and make sure there are no solder bridges. I think some people put a layer of clearcoat over them, but that might make future mods or repairs a bit harder.

[davent]

I use the same waterbased lacquer that i use to clearcoat  the enclosure. I just shoot a couple light coats and that solves the oxidation problem, some people use candy coloured transparent lacquers like Testors' to give it a solder mask look. When you go to solder the lacquer vaporizes at the touch of the soldering iron so virtually no issues to deal with, works great!

I use to use MG Chemicals tinning product but the lacquer works better and looks better too.

dave

[Gurner]

google sk-10 flux spray...it's a clear lacquer that prevents copper oxidzation yet it can still be soldered over.

[The Rocket From The Tombs]

Oooh, the flux spray looks promising! I was thinking about the sharpie as something I could use for a quick fix for this particular board, until I can go out and get something more professional for future boards.

[Gurner]

Oooh, the flux spray looks promising! I was thinking about the sharpie as something I could use for a quick fix for this particular board, until I can go out and get something more professional for future boards.

it should work, but I reckon a sharpie 'coloured over' pcb copper track would look worse than the oxidization itself!

[Mark Hammer]

After I etch my boards, I buff them and take a Q-tip cotton applicator swab and spread out some liquid flux over the board to cover the traces.  I like to tin the boards with solder after I do that, but if I don't feel like it or have the time, I can just leave the flux on.

But you know, it's not a BAD thing to buff the board, wrap it in plastic food wrap or stick it in a resealable plastic sandwich bag until you're ready to use it, and then just give it a quick once over with fine steel wool when the time comes to populate it.

[Seljer]

I haven't had any issues with spraying a finished (and cleaned) board with a coat of lacquer, even when it came to repairing it later.

Enameled wire is coated in polyurethane (or sometimes other things) and it works great as an insulator.

[The Rocket From The Tombs]

Thanks for the responses guys! as far as the look of the board, I'm not too concerned with that.

[mremic01]

Nail polish might be a good compromise. A little less easy to apply  than Sharpie, but you'd get a better seal over the copper and you can avoid getting it on the pads to allow for future soldering. 

[davent]

It's the pads that you don't want to oxidize, the rest doesn't matter.  The oxidation creates soldering difficulty.

[Kesh]

The dielectric properties of these products may increase stray capacitance between traces. Some lacquers are designed to reduce this problem.

[R.G.]

Sharpies are filled with a form of lacquer.

For board passivation use, spray lacquer is likely to be more efficient to use than going over it with a sharpie.

[mremic01]

It's the pads that you don't want to oxidize, the rest doesn't matter.  The oxidation creates soldering difficulty.

Well then I'm confused. What's the point of going over them with anything at all? Once they've got a nice solder joint, won't the be protected from oxidation? I've always been worried about the traces running between pads. Unlike professionally fabricated PCBs, etched PCBs don't have a mask over them, so they're exposed to air, which I thought might corrode them over time. They tend to be thin enough that I could see them oxidizing to the point of not being reliable.

[Electron Tornado]

An electronics tech I know says he uses clear nail polish on the copper traces. I've also used solder to cover traces.

[Mark Hammer]

It's the pads that you don't want to oxidize, the rest doesn't matter.  The oxidation creates soldering difficulty.

The pads are for the things that are supposed to go there.  Sometimes, you end up wanting to pop a few post-build holes in the board for parts that weren't in the original design, but help extract more from it, or to run wires out to toggles to make something more flexible.   I'm in complete accord with your rationale of "Don't knock yourself out about things that don't really matter".  I just happen to be one of those people for whom traces often represent as critical a landing spot as pads do.

And it's not just for adding parts, either.  Sometimes, one of the most useful aspects of a debug is to cut a trace and isolate something.  When the problem is identified and fixed, an oxidized trace is not quite as receptive to bridging that gap again with a tiny piece of resistor lead.

So, long story short, I find it helpful, for my own purposes, to make sure the whole board is tinned.  I see enough oxidized copper every day looking out at the roof of the Parliament buildings.    But I can fully understand where it is not quite AS critical for many others.

[mremic01]

I kind of like the idea of continuous solder-flow from pad to pad. It's almost like point to point and makes me feel a warm and fuzzy about my builds.

Recently I've started leaving strips of copper on the edges of the PCB. If I need to, I can drill holes into them and use them for extra components in mods. I just put a Rat together with two caps on one side and si diodes and leds on the other. Instead of wiring them onto the switch, they're all nice and secure on the PCB and I can just run wires to the switch.

[Electron Tornado]

Recently I've started leaving strips of copper on the edges of the PCB. If I need to, I can drill holes into them and use them for extra components in mods.

When I etch I make traces and pads large, and try to leave as much copper on the board as I can. It makes it easier to get things lined up to drill for an IC socket, for example, and gives me some wiggle room if I make a mistake (like forget a wire) or want to mod something later. I also think that big traces and big pads decrease the chances of having a pad lift off the board.