Hi
I've got some second hand Jensen transformers & fired up free Eagle version and made a small PCB to test them.
I'm using the PCB toner transfer method and mixed two parts of Muriatic acid with 1 part of peroxid, but it isn't etching the copper, or it is working but very slow. I waited one our and still much copper on board.
I remember having done the same some long time ago for other PCB's and as soon as I added the PCB the solution started to bubble and it was a fast procedure. If I used a brush or a finger to rub, it was also faster.
Funny is if I try it with a nail or a wood screw, it starts to bubble and etches it.
I also remember the peroxid used before was of strong industrial type like 100 or 1000%
The acid used is probably OK since I use it to clean rust on ceramic tiles.
What am I missing ?
The peroxid was sitting too long and has loosen the strength ?
Does it also work with ordinary 3-5% drug store or pharmacy peroxid ?
Thank You.
I've got some second hand Jensen transformers & fired up free Eagle version and made a small PCB to test them.
I'm using the PCB toner transfer method and mixed two parts of Muriatic acid with 1 part of peroxid, but it isn't etching the copper, or it is working but very slow. I waited one our and still much copper on board.
I remember having done the same some long time ago for other PCB's and as soon as I added the PCB the solution started to bubble and it was a fast procedure. If I used a brush or a finger to rub, it was also faster.
Funny is if I try it with a nail or a wood screw, it starts to bubble and etches it.
I also remember the peroxid used before was of strong industrial type like 100 or 1000%
The acid used is probably OK since I use it to clean rust on ceramic tiles.
What am I missing ?
The peroxid was sitting too long and has loosen the strength ?
Does it also work with ordinary 3-5% drug store or pharmacy peroxid ?
Thank You.
Peroxide does lose strength.
Pharmacy first-aid peroxide is very very weak, because your body is not as tough as metal.
Pharmacy first-aid peroxide is very very weak, because your body is not as tough as metal.
The acid should be warmed to 40C or so. Constant agitation is needed. Rubbing will remove the resist, just agitation or flow is safest.
Don't play with strong peroxide, its thoroughly evil. You don't need an oxidizing acid to dissolve copper, just a strong acid. Oxidizing acids may attack the FR4 or other plastics and char them.
Don't play with strong peroxide, its thoroughly evil. You don't need an oxidizing acid to dissolve copper, just a strong acid. Oxidizing acids may attack the FR4 or other plastics and char them.
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"I also remember the peroxid used before was of strong industrial type like 100 or 1000%"
You are not making any sense here.
Do you even understand %?
30 to 32 % hydrogen peroxide is what I have seen in the lab.
You are not making any sense here.
Do you even understand %?
30 to 32 % hydrogen peroxide is what I have seen in the lab.
I think that's the old way, measuring the _volume_ of O2(g) / volume H2O2(aq) - as percentage that can easily be > 100%. By weight, obviously not...
1) never never ever ever put a finger there.
If too hurried or if you want to etch faster some "slow" area you *may* use a piece of sponge , held with dental type long nose pliers or even a gloved hand, but that generally means copper surface is dirty.
You must clean it very well with steel wool or very fine wet dry emery paper 400 grit or higher, then degrease with pure alcohol or some solvent and never ever touch it again with your hands which are greasy even if just washed, then apply toner, then etch.
2) your peroxide is dead.
Muriatic/clorhidric acid is stable , son it´s not your problem.
Wound treatment peroxide is 3%, some call it "10 volume" because nominally 1 cc gives you 10 cc free oxygen, it *does* work but is slow, you might mix 3 peroxide to 1 acid if nothing else available.
What I and most everybody use is hairdresser hair dying/decoloration type which is often bought in specialized "hair supplier" stores,it´s "30 volume" or 8%, much stronger and it already burns your skin white if pure.
Do NOT buy hair dying kits in desperation (I have 🙁 ), they only bring, say, 50cc or less, but much worse, are mixed with some "skin protector" such as glycerine or lanoline, which completely ruin the mix, you need the pure stuff, which looks like pure water.
3) strong mineral acids, such as clorhidric, nitric, sulfuric (VERY dangerous) will etch copper on their own, but act slow.
The combination is very fast, because it´s a synergistic mix, one helps the other: peroxide oxidizes copper, and copper oxide dissolves very fast in acid, much faster than bare metal.
My troubleshooting is (when reusing old/stale mix from earlier jobs): if copper becomes orange red, I am missing acid (surface oxidized but does not dissolve) so I add some; if surface is bright shiny but "nothing happens" then I am missing oxygen, what I guess is happening to you; if proportions are right it etches very fast, in a few minutes.
Of course best is to work with fresh chemicals in proper proportions.
I buy "30" volume 8% peroxide, no additives at all at a haidresser supplier by the 5 liter jug, put it inside 3 or 4 black bags and keep it in a *dark* place, ideally in a room which never ever gets sunlight , even indirect, UV is your enemy.
Kept that way, it lasts 1 or 2 years.
I silkscreen my own PCBS in 40-80 batches (I commercially make Guitar Amps) and have a 30 liter heated Iron Perchloride bath but now and then I must make a prototype or a single custom job which does not justify burning a screen, there I use toner transfer (generally cold transfer by chemical-solvents, not ironing) and acid/peroxide bath.
Me too - I just looked up the electrochemistry of copper - HCl alone won't attack it normally, hence the need for additives, though I've also seem other acids used such as nitric acid, sodium persulfate, or a mix of FeCl3 and HCl.
Note that disposal of used etchant is an issue. Copper salts are poisonous. Perhaps the best approach is dry out the used etchant into a powder and bag it (labelled!) for future disposal.
After reading all this, boy am I glad for sorta cheap pcbs from jlcpcb. Happy/ safe etching folks
They are certainly a blessing for many/most.
Specially if you *need* 2 or more layers, plated through holes and vias, gold plating, the fancy stuff, that´s beyond the practical end for DIYers.
For me who design and prototype all the time, I need them NOW and not in 15 days, just to be assembled, tweaked and modified within the hour is priceless.
Also cost, I can get a 3 ft by 4 ft single face FR2 phenolic board for U$47 , do the Math.
Musical Instrument amp PCBs are often huge, not because of component density (which can be very low) but because they must match end to end panel distribution of jacks, pots and switches.
Chinese charge by the sq. cm so costs skyrocket quickly in those cases.
Specially if you *need* 2 or more layers, plated through holes and vias, gold plating, the fancy stuff, that´s beyond the practical end for DIYers.
For me who design and prototype all the time, I need them NOW and not in 15 days, just to be assembled, tweaked and modified within the hour is priceless.
Also cost, I can get a 3 ft by 4 ft single face FR2 phenolic board for U$47 , do the Math.
Musical Instrument amp PCBs are often huge, not because of component density (which can be very low) but because they must match end to end panel distribution of jacks, pots and switches.
Chinese charge by the sq. cm so costs skyrocket quickly in those cases.
Math is part of doing business. You have to factor in all the other costs, compare your pcb costs to all the others to see how much percentage it is and how much the pcb cost affects the final outcome.
For me at least, it is a week to receive a new batch from jlcpcb. I sell blank and assemble pcbs so pro pcbs is the only way in my case. If you are able to use home made pcbs, in your products, great but you also have to factor in your time( drilling, cutting), chemicals, disposal, yield etc. Even having a silkscreen layer is helpful in assembly and ultimately will save time. It depends on who does the assembly and how well they know the design. All my designs are 2 layer, HASL, Au plate is not required unless you need the coplanarity for smt.
For me at least, it is a week to receive a new batch from jlcpcb. I sell blank and assemble pcbs so pro pcbs is the only way in my case. If you are able to use home made pcbs, in your products, great but you also have to factor in your time( drilling, cutting), chemicals, disposal, yield etc. Even having a silkscreen layer is helpful in assembly and ultimately will save time. It depends on who does the assembly and how well they know the design. All my designs are 2 layer, HASL, Au plate is not required unless you need the coplanarity for smt.
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I'm always getting excellent results with 10-15% HCl solution mixed with 30% hydrogen peroxide in about 4:1 ratio. It takes literally a minute to get the job done. Handle with care, it's much more aggressive than a ferric chloride.
I use an etching cuvette and as an etchant I use sodium persulphate. I let the bath heat up to 45°C to 50°C, then I put the circuit board in and turn on the air pump. The etching process is accelerated by blowing in air.