I accidentally bought double-sided copper clad. I'm using muriatic+hydrogen peroxide etchant. Since I've heard some people needed to add copper wire to get theirs going, I thought I'd be ok, since the extra copper would just make my etchant stronger.

Not really. I tried etching both sides simultaneously (completely removing the side I don't need), but the lines on my trace side starting getting eaten away before the blank side was gone.

So I hatched a scheme: tape off one side, etch off the other. Now I have single-sided copper. Works, but it takes twice as long, and by the time I get to actually etching my traces, the etchant is kind of sluggish.

Anybody have any clever ideas? Is it possible to remove a side of copper without etching? Anybody want to trade some single-sided for double?

I did it the ghetto way, with a dremel.  Not reccomended!  (But it works)

How do you mean? You ground it off with some sort of grinder attachment?

What if you sliced it down the center and then had two very thin single sided copper boards?

Use 40% Peroxide solution!

I etched (2) 3" x 5" double sided pcb's in about 2 minutes with that mix... no masking, no adding extra copper, just etchant that was almost too fast.. next time I am going to play around with the mixture and see if I can get it a little slower....

Make sure you have a good transfer and you should be ok. I prefer to use double sided PCB because then the board is translucent and it makes it easier to line up the transfer for the component side!

What if you place your layouts on both sides, just not over top of each other? That way you get rid of the copper on both sides and get a couple boards out of it.

Quote from: MicFarlow77 on July 04, 2009, 12:03:17 AM
Make sure you have a good transfer and you should be ok. I prefer to use double sided PCB because then the board is translucent and it makes it easier to line up the transfer for the component side!

Mic: Do you mean IF the board is traslucent it is easier ? 
I have bought double sided too: is the easiest way of using it (boht sides to contribution) is with alining both transfer papers together with two holes that are pointed on both patterns ?

I think I am not sure to understand well...

Tape off one side and etch the circuit on the other. Drill the lead holes, i usually use ~ #70 drill bit. Take a much larger diameter drill bit (i tried an 11/64") and chamfer the holes removing the copper from around lead holes on the unetched side of the board, just spin the bit with your fingers you don't want to go through the board. It's not hard to remove enough copper around the hole so that there's no danger of a lead shorting to the copper plane.

You could create a mask that just allows etching  small patches where the leads come through, more work but same result.

dave

A double sided copper clad board could be used on both sides ?  Why waist it ?  Keep it for a future project with two sides.    But sincerly I used some of mine in some Manahttahan style buildts.  Keep one side at ground and the oyher a 4.5V.  Glue islands with crazy glue for the components and get the other desired voltages with jumpers and holes for the 0V or 4.5V refs.

I have a large stock of double-sided copper clad, and have found that it only takes a couple minutes to sand off one side with a belt sander.  I usually stop sanding before it's completely gone, and let the etchant take off the rest.  My sander is a 4-inch wide bench sander.  It would probably be very tedious to attempt this with a less capable sander.

There is a special drill bit which has a tiny pip in the center and which cuts a nice circle around the hole, making an isolated donut of copper anywhere you have a guide hole.

Of course, the last time I saw these was at least 20 years ago. 

I accidentally bought double sided vero once. I still have it, the traces run horizontal on the bottom and vertical on the top. Or is it vertical on the bottom and horizontal on the top?

Quote from: R.G. on July 04, 2009, 11:42:33 PM
There is a special drill bit which has a tiny pip in the center and which cuts a nice circle around the hole, making an isolated donut of copper anywhere you have a guide hole.

Of course, the last time I saw these was at least 20 years ago. 

I found the hand tool version of that buried at my work's electronics lab, neat tool.  You could make a ground plane on a DIY'd etched board with it.  It's also good for cutting traces when modding a PCB.

for applying resist to a whole side, spray it with lacquer from a can

Mmm.  Groundplane.   

Quote from: Taylor on July 03, 2009, 10:58:13 PM
How do you mean? You ground it off with some sort of grinder attachment?

Not a sanding wheel but, a cut off wheel gently dragged over the surface.  Again, not recommended.

Well, I found a reasonable way to remove the other side. A lot of the ideas above were quite clever, but more time-consuming than I was willing to do.

What I did was slice one side of copper away from the substrate on a corner, peeling it off as far as my utility blade could do. Then, using pliers, I started pulling the copper off. It came of in about 3 sections. Kind of a PITA, but faster and easier than other options I've heard so far. It leaves the components side with a texture - you can feel the woven fiberglass(?). I don't mind it, but some might, so I thought I'd mention it.

Note to future etchers - BUY SINGLE-SIDED! I found I'm not the only one who's made this mistake here.

I`ve found it possible to do this also. By careful manipulation you can actually peel away the copper on one side. If you score it on one side you can, when snapping the substrate, leave the copper on the other side intact and then gently wiggle it from side to side till it comes away. Easier to do than describe.

If its fr4 board (fibreglass) it is possible to slice the board right down the centre creating two sigle sided pices of half the thickness. its tricky to do and may or may not work, how i have done this in the past is to use a sharp knife like a stanley blade and wiggle along one of the corner edges until you get a split in the pcb material, then its a case of sliding into the split a larger flat blade and as you twist it splits the fibre right along the centre. It works because fibre glass fr4 type board is built in layers. This sounds like a pain to do but in realaityonce you get the thin blade in and start to seperate the board it slices easily and only takes a few minutes.I hope this explanation makes sense

SORRY you already done this. It took me too long to type this, lol

Quote from: Ice-9 on July 10, 2009, 05:27:26 PM

SORRY you already done this. It took me too long to type this, lol

Sounds like you`re describing a different technique. I admire your patience and dexterity.