EEVblog Electronics Community Forum

Electronics => Beginners => Topic started by: lordvader88 on June 14, 2019, 10:33:34 pm

Title: Dead bug copper clad prototype board advice ?
Post by: lordvader88 on June 14, 2019, 10:33:34 pm
I haven't used any yet, how should I clean and de-oxidize the copper before use , I have iso-alcohol and weak solder resin?

I want to make some cool RF projects soon, what's some advice for making isolation channels, or islands, I need super glue I guess. I have hot glue, is that any good ?

what tools make nice clean cuts in the copper ?
Title: Re: Dead bug copper clad prototype board advice ?
Post by: cur8xgo on June 14, 2019, 10:37:53 pm
I haven't used any yet, how should I clean and de-oxidize the copper before use , I have iso-alcohol and weak solder resin?

I want to make some cool RF projects soon, what's some advice for making isolation channels, or islands, I need super glue I guess. I have hot glue, is that any good ?

If memory serves me right you may see good examples of dead bug RF and RF PCB prototyping techniques in general in:

ARRL handbooks
Robert Pease writings
Art of Electronics
Title: Re: Dead bug copper clad prototype board advice ?
Post by: ogden on June 14, 2019, 10:57:24 pm
I have hot glue, is that any good ?

Wow, No!!!!   :o

You need thermally stable glue because when you solder something onto island it is heated over 250oC. Hot glue will just melt away or even vaporize.
Title: Re: Dead bug copper clad prototype board advice ?
Post by: bd139 on June 14, 2019, 10:58:55 pm
I make a ton of stuff in this way.

Just clean it with an abrasive pad of some sort. I usually use a scotchbrite type thing. No chemicals are needed.

As for the islands, get some 0.8mm thick single sided FR4 PCB and some good scissors and cut it into strips. Then glue down with superglue. Do not use hot glue - it'll melt the moment you solder anything!

As for cutting the main FR4 substrate I use the following tools:

1. Scribe for marking it (copper side)
2. Metal rule for measuring (duh)
3. Engineers square for angles
4. Aviation shears for cutting it.

The latter go through the stuff like butter and makes very accurate cuts but requires some practice.

Here's a pile of stuff I made recently as an example of technique:

(https://i.imgur.com/zYiYNRH.jpg)

Try and build bits of circuits in modules, then test them, then assemble them later. Involves less pain then.

I call my technique "manflattan" as it's manhattan style but flat because I bloody hate all those excess bits of lead sticking up plus it's horrid at VHF and above.
Title: Re: Dead bug copper clad prototype board advice ?
Post by: wilfred on June 15, 2019, 01:18:59 am
What determines when a PCB might be a better option? Some of those circuits look pretty complex and not less work than etching a PCB. I'm guessing a solid ground plane factors in here somewhere.
Title: Re: Dead bug copper clad prototype board advice ?
Post by: lordvader88 on June 15, 2019, 03:52:54 am
(https://i.imgur.com/zYiYNRH.jpg)

IDK what that is but it looks super cool. I've seen people use a fibre-glass brush on copper traces, I've been meaning to get 1.

I know some basic chemistry, but I don't know off hand what what works with copper. 1 thing people worry about when using acids on copper, is leaving residues that act over time. Well why don't they just clean the lot with a base ? For hobby level stuff that should be ok
Title: Re: Dead bug copper clad prototype board advice ?
Post by: lordvader88 on June 15, 2019, 03:55:08 am
So 1 board is the GND plane, and I cut up a 2nd board to make conductive islands to glue down, correct ?

More reason to get a FX-888 soldering iron as well.
Title: Re: Dead bug copper clad prototype board advice ?
Post by: Psi on June 15, 2019, 04:01:51 am
Yep, as others have said. Use a scotchbrite/pad.
Those abrasive cleaning pads you use in the kitchen to clean pots and pans.

You can also use a normal cloth with some abrasive cleaner, that stuff that feels 'gritty'.

Give the copper a really good scrubbing and then wash off and wipe with iso + clean cloth.

You will find it solders really nicely after that.

If the board is very very old and dull/oxidised you can try some 1000 grit sandpaper but this is usually not needed.
Title: Re: Dead bug copper clad prototype board advice ?
Post by: lordvader88 on June 15, 2019, 04:35:51 am
Do u mean the non metal plastic type pads, often dark green colored in my part of Canada ? I think u mean nonn metal pads right ?

I do have things like 8k grit sand paper and grinding stones, but no actual polishing grit in a jar.... I have those green scotchbright pads tho, I'll try that

But for that matter, I bet if u took average sedimentary rocks that are found all over the world, that crush easy and finely, you could use that as an abrasive slurry to polish copper. Remember that after nuclear war
Title: Re: Dead bug copper clad prototype board advice ?
Post by: Psi on June 15, 2019, 04:43:06 am
yes, the pads are green and not metal.

That said, a metal pad would probably work.  but i think the green ones are higher 'grit' equivalent so are better for pcbs.

I used to use paper towels and JIF brand cream cleaner when i did pcbs.  It achieves the same result, it's just the cleaner is the grit instead of the pad.
Title: Re: Dead bug copper clad prototype board advice ?
Post by: KL27x on June 15, 2019, 06:37:06 am
Stainless steel wool, like you buy for pots and pans. It works great or shining up copper clad. Drop of soap, spritz of water, scrub a dub. Rinse, dry, wipe with a layer of rosin. No dust.
Title: Re: Dead bug copper clad prototype board advice ?
Post by: IconicPCB on June 15, 2019, 06:47:06 am
Simpler yet a few crystals of tartaric acid ( cream of tarter) a food sour additive from supermarket.
Wet tarnished copper, sprinkle, rub, let pickle for a few minutes rinse for tarnish free finish.
Title: Re: Dead bug copper clad prototype board advice ?
Post by: RoGeorge on June 15, 2019, 07:04:29 am
https://www.youtube.com/watch?v=kH110yjYZ2g (https://www.youtube.com/watch?v=kH110yjYZ2g)

For cleaning the copper clad, I use to use toothpaste and a cloth or some paper tissue. Do not put much water, no water, or a drop or two at most, then cleanse the PCB in running water.

Alternatively, the harsh part of dish washer sponges works pretty well, too, for cleaning the oxide layer.

There is no reason to use harsh chemicals, the copper will oxidase back immediately.  The flux will remove the remaining layer anyways.  Unless you have ancient PCB, with dark brown oxide layer, you will probably not need cleaning it at all.  Usually the flux is enough.  If not sure, test it.  The solder should "wet" the copper clad.  If the solder tends to stay in bulges/droplets it needs cleaning.

Important thing while cutting the PCB:  avoid power tools that will throw fibers in the air while cutting, like a dremel tool, or at least wear a respiratory mask.  It's not smart to put fiber glass in your lungs.

https://www.youtube.com/watch?v=uBkPX_QhRI0 (https://www.youtube.com/watch?v=uBkPX_QhRI0)

Happy RF tinkering.
Title: Re: Dead bug copper clad prototype board advice ?
Post by: HB9EVI on June 15, 2019, 07:07:09 am
Practically I'm not using any other technique than that, using a dremel bit for island cutting:

https://www.dremeleurope.com/ch/de/fraeser-hss-4-8mm-134-ocs-p (https://www.dremeleurope.com/ch/de/fraeser-hss-4-8mm-134-ocs-p)

they're available in 3 different sizes

before working I'm cleaning up the pcb with steel wool
Title: Re: Dead bug copper clad prototype board advice ?
Post by: RoGeorge on June 15, 2019, 07:21:53 am
One more thing when doing RF PCBs:  leave room for shielding.

Most of the time, shielding is crucial for RF stability.

https://www.youtube.com/watch?v=fpD_mDCViPE (https://www.youtube.com/watch?v=fpD_mDCViPE)
Title: Re: Dead bug copper clad prototype board advice ?
Post by: KL27x on June 15, 2019, 08:38:05 am
Quote
There is no reason to use harsh chemicals, the copper will oxidase back immediately.  The flux will remove the remaining layer anyways.  Unless you have ancient PCB, with dark brown oxide layer, you will probably not need cleaning it at all.  Usually the flux is enough.
 
Yes, if you get the copper wet, it will surely oxidize a bit right after cleaning and drying it. As you say, it's not a big deal if you use the board in short order. But over time it will generally get worse and it can be a bit annoying. Even with a good flux, you will need to use MORE flux and longer dwell times.

Now that I'm thinking about it, the rosin flux coating would be a PITA for protoboard due to all the holes. I apply rosin flux to homemade PCBs by squirting a bit onto the board and then wiping it around with a bit of paper towel. It dissolves the rainbow sheen of microns-thin oxide that is already forming on the copper just seconds after drying it off. And the thin layer of rosin flux dries out in a few minutes, forming a protective layer against moisture and air. The board stays bright and shiny for months and the dried rosin flux aids with soldering. In the past I have used car wax, but I think rosin flux protects for longer
Title: Re: Dead bug copper clad prototype board advice ?
Post by: StuartA on June 15, 2019, 09:30:50 pm
My preference for cleaning copper board is the very fine steel wool used by furniture restorers. It's much more gentle than the stuff that, say, a plumber might use. It's essential that you follow that with a really good wipe using IPA on a tissue.

For one off-jobs, I've been using stripboard a lot, but I keep thinking that I ought to re-visit dead bug again.
Title: Re: Dead bug copper clad prototype board advice ?
Post by: lordvader88 on June 16, 2019, 01:08:33 am
ok I have the basics then , and I have tin snips, oh I just need superglue
Title: Re: Dead bug copper clad prototype board advice ?
Post by: windsmurf on June 16, 2019, 03:45:18 am
... why do they call this "Dead bug"?
(https://us.123rf.com/450wm/refluo/refluo1708/refluo170800016/83874621-stock-vector-defeated-bedbug.jpg?ver=6)
Title: Re: Dead bug copper clad prototype board advice ?
Post by: Arjunan M R on June 16, 2019, 04:26:38 am
... why do they call this "Dead bug"?
(https://us.123rf.com/450wm/refluo/refluo1708/refluo170800016/83874621-stock-vector-defeated-bedbug.jpg?ver=6)
I think most of them die with their legs upside down(don't know)  :D
if you put a DIP package upside down they look like dead bug.
Title: Re: Dead bug copper clad prototype board advice ?
Post by: Zero999 on June 17, 2019, 03:15:32 pm
An ink eraser, the gritty rubbery type, is good cleaning copper clad board.

Be careful with cyanoacrylate (super glue), it gives off nasty fumes when overheated.
Title: Re: Dead bug copper clad prototype board advice ?
Post by: james_s on June 17, 2019, 03:54:50 pm
I don't clean it at all unless it's contaminated with something or really oxidized. The flux cleans it right up.
Title: Re: Dead bug copper clad prototype board advice ?
Post by: tpowell1830 on June 17, 2019, 04:27:12 pm
If  you're doing RF dead bug style checkout W2AEW at:

https://www.youtube.com/channel/UCiqd3GLTluk2s_IBt7p_LjA (https://www.youtube.com/channel/UCiqd3GLTluk2s_IBt7p_LjA)

If you use copper clad, it is called Manhattan style.