Drilling before Eching

I have never seen instructions that say to drill before etching.Why?
Are there any problems if drilling before eching?
I will be drawing the circuit lines with an etch resist marker.

I guess with press'n'peel, you would drill last.

Hi!

The only problem is if you want to galvanize your pists to prevent corrosion. The solder would obstruct the holes. If you use your board without anything else, you can drill before etching.

whats a pist?

Hi!

Excuse my english. I'm a french speaking person. I was talking of the copper wire. Ok?

ok, thanks JFDuval.

I've never drilled the pcb before the etching process, because I thought the etchant might undercut the copper around the drill hole, leaving less copper pad than I had intended. Have you ever run into that problem JFDuval?
JB

Hi!

For the moment, I ever drill before etch because I transfer with a pen and I use holes as a repere. I don't ever see that it was more attacked near the holes.

Drilling before etching causes an undercut around the hole, making it later more difficult to solder as the copper land is some distance from the hole's edge.
Also, if your etching (before drilling) was good, you should have a tiny mark etched at each drill position, giving you a place for the drill to start cutting without wandering about.

The only time the holes are drilled before etching is when they go through the plate through hole process, something out of reach for the home PCB maker.
Klaus