Good LORD!!!!
I am not nearly so elaborate.
I do use clean copper boards, freshly scrubbed with my special super secret degreaser from my chemistry lab (my "real" job is a chemist). With printouts on Epson Premium Photo Glossy from an HP 5M printer with standard toner, I crank up my household iron to linen, put some kitchen parchment paper (NOT wax paper!!!) over the back of the Epson paper to avoid stickiness, press the iron firmly on the printout for about 90 seconds, then I go back over the whole board really well with the edge of the iron. I think this last part is pretty important since I always seem to get loose traces if I fail to "scrape" the boards properly with the edge of the iron.
Anyway, no vacuum press nor press-n-peel for me, though I am sure it would be nice if I had it!!!
David
PS I find it funny that I am more than willing to spend hundreds of dollars on caps, resistors, and transistors, but I haven't shelled out a couple of bucks to try press-n-peel!
I am not nearly so elaborate.
I do use clean copper boards, freshly scrubbed with my special super secret degreaser from my chemistry lab (my "real" job is a chemist). With printouts on Epson Premium Photo Glossy from an HP 5M printer with standard toner, I crank up my household iron to linen, put some kitchen parchment paper (NOT wax paper!!!) over the back of the Epson paper to avoid stickiness, press the iron firmly on the printout for about 90 seconds, then I go back over the whole board really well with the edge of the iron. I think this last part is pretty important since I always seem to get loose traces if I fail to "scrape" the boards properly with the edge of the iron.
Anyway, no vacuum press nor press-n-peel for me, though I am sure it would be nice if I had it!!!
David
PS I find it funny that I am more than willing to spend hundreds of dollars on caps, resistors, and transistors, but I haven't shelled out a couple of bucks to try press-n-peel!
Yes, the vacuum system is elaborate, but since we use it a lot at work it was worth the effort.
[brag] I used it to make double sided flex circuits (thats copper on Kapton film) with track and space sizes of 0.005" ! Yes, thats 5 thousandths of an inch, not a typo. Not bad for a laser print, eh? Especially since prototype flex costs at least $1000 and takes a week ( I can make it in the kitchen in an hour). [/brag]
Still haven't figured out how to do real pth, though ...
[brag] I used it to make double sided flex circuits (thats copper on Kapton film) with track and space sizes of 0.005" ! Yes, thats 5 thousandths of an inch, not a typo. Not bad for a laser print, eh? Especially since prototype flex costs at least $1000 and takes a week ( I can make it in the kitchen in an hour). [/brag]
Still haven't figured out how to do real pth, though ...
I use scotchbrite, but it is essentially the same thing as steel wool without the "splinters" and rust. So far, the limiting component has been that I have used too aggressive etchants. I have concentrated reagents in my lab and "forgot" to dilute them correctly before etching.
HCl and H2O2 mixed worked rather well, though a little "too" well the first coulple of rounds. I think I just about have it right now.
HCl and H2O2 mixed worked rather well, though a little "too" well the first coulple of rounds.
I think I just about have it right now.
Nah, this mix is pretty tame. Remember, I am a chemist and work with things like triflic acid, elemental bromine, and other such REALLY nasty stuff on a regular basis. On the flip side, once you neutralize it, the HCl/H2O2 mix is completely inert. The ferric chloride, conversely, is a pain to dispose of. I'll stick with what I have had success with, but thanks for the concern.Nordic said:
David
I've been using the HCl/H2O2 mix for years, when our machines have been down..or for other ad hoc use.
Originally, we used Ferric chloride, but we found it rather messy with all the stains, so we switched to Sodium persulphate in the machine.
The recipee I once found for HCl/H2O2 called for a 1:1:2 mix of HCl:H2O2:water, and HCl and H2O2 both being 40% dilutions.
I have tried to keep this strength, as it gives reasonably fast end well controlled etching.
I could be interesting to hear a chemists opinion on this process, though....
Originally, we used Ferric chloride, but we found it rather messy with all the stains, so we switched to Sodium persulphate in the machine.
The recipee I once found for HCl/H2O2 called for a 1:1:2 mix of HCl:H2O2:water, and HCl and H2O2 both being 40% dilutions.
I have tried to keep this strength, as it gives reasonably fast end well controlled etching.
I could be interesting to hear a chemists opinion on this process, though....
Well, I have nothing to add!! That is exactly what I use. I tried a bunch of other acids (most notably Nitric and Sulfuric) but neither were as well behaved as simple HCl. The H2O2 is, of course, there as an oxidixing agent to get the copper on the boards to Cu2+ more easily. Nitric acid by itself worked OK, but it wasn't very well behaved with my experiments (though they were fairly limited). The HCl/H2O2 mix is just too clean with regard to cleanup and ease of use. I found something that worked well and have stuck with it.AuroraB said:
Hi
I use an injet printer with transparency setting and best printing quallity and the paper i use is a semitransparent paper which is usually used for drawings but a thick one because there is also a very thin like cigarete paper.
Then i use a PCB with a photo sensitive coating and put it under a solariun lamp (Phillips cleo 60cm 40w sun lamp) for 9min.
The PCB then goes to a bath containing warer and NaOH
and after that etching is done with Hydrochloric Acid and Hydrogen Peroxide about 4 to 1 (the Hydrochloric Acid is 14% from any market).
Using this method the pcbs look pretty sharp.
I forgot to say that i convert all the pcb designs to vector graphic image before i print it which gives a very clean printout.
Alex
I use an injet printer with transparency setting and best printing quallity and the paper i use is a semitransparent paper which is usually used for drawings but a thick one because there is also a very thin like cigarete paper.
Then i use a PCB with a photo sensitive coating and put it under a solariun lamp (Phillips cleo 60cm 40w sun lamp) for 9min.
The PCB then goes to a bath containing warer and NaOH
and after that etching is done with Hydrochloric Acid and Hydrogen Peroxide about 4 to 1 (the Hydrochloric Acid is 14% from any market).
Using this method the pcbs look pretty sharp.
I forgot to say that i convert all the pcb designs to vector graphic image before i print it which gives a very clean printout.
Alex
You can also take a look to the following links
http://www.opencircuits.com/Chemical_Etchants
About half way down, in the PCB section
http://web.telia.com/~u85920178/data/pcb2.htm
Alex
http://www.opencircuits.com/Chemical_Etchants
About half way down, in the PCB section
http://web.telia.com/~u85920178/data/pcb2.htm
Alex
dfdye,
Ive been using the mix of 1 part HCL to 2 parts H2O2 for some time now with great results. The etch time is about 3 minutes using 3% H2O2, and less than 1 minute 45 seconds using 6% H2O2. Its cheap too, about $0.38 per cup of solution.
I also use Red Devil Drain cleaner (Sodium Hydroxide, aka Lye) mixe 1/2 teaspoon to 300 ml of lukewarm tap water. This mix will develope positive-sensitized PCB in less than a minute. The cost is about $0.15 per batch.
When finished I mix both the developer and etchant together before disposing.
I would like to know at what ratio will the two become inert?
Thanks for your help
Ive been using the mix of 1 part HCL to 2 parts H2O2 for some time now with great results. The etch time is about 3 minutes using 3% H2O2, and less than 1 minute 45 seconds using 6% H2O2. Its cheap too, about $0.38 per cup of solution.
I also use Red Devil Drain cleaner (Sodium Hydroxide, aka Lye) mixe 1/2 teaspoon to 300 ml of lukewarm tap water. This mix will develope positive-sensitized PCB in less than a minute. The cost is about $0.15 per batch.
When finished I mix both the developer and etchant together before disposing.
I would like to know at what ratio will the two become inert?
Thanks for your help
<snip>
I would like to know at what ratio will the two become inert?
I'm not a chemist, didn't even take high school chemistry. Anyway here is an experiment I did with the chemicals, to try and answer my own question.
It been a while sense the last post so, remember the etch solution is made up of 1 part 31% Hydrochloric acid (HCl), 2 parts 3% Hydrogen Peroxide (H2O2). The developer is made up of 1/2 teaspoon Sodium Hydroxide in 300ml water.
Hydrochloric acid (HCl) is very acidic, PH1. Sodium Hydroxide (NaOH) is very alkaline, PH14. When you mix an acid with an alkaline and adjust the solution to PH7 they become table salt and water. HCl + NaOH = NaCl + H2O2
I took the spent etchant and developer and adjusted them to PH7. I let the solution set for about 12 hours and a blue sludge that I believe to be copper hydroxide formed at the bottom of the container, and salt water formed at the top.
I siphoned off most of the water being careful not to disturb the sludge.
I tested the PH of the water and it is still PH7, and is crystal clear.
I have reduced the 3 liters of chemicals down to ~250ml of sludge.
Am I on the right track?
Is the blue sludge copper hydroxide?
I would like to know at what ratio will the two become inert?
I'm not a chemist, didn't even take high school chemistry. Anyway here is an experiment I did with the chemicals, to try and answer my own question.
It been a while sense the last post so, remember the etch solution is made up of 1 part 31% Hydrochloric acid (HCl), 2 parts 3% Hydrogen Peroxide (H2O2). The developer is made up of 1/2 teaspoon Sodium Hydroxide in 300ml water.
Hydrochloric acid (HCl) is very acidic, PH1. Sodium Hydroxide (NaOH) is very alkaline, PH14. When you mix an acid with an alkaline and adjust the solution to PH7 they become table salt and water. HCl + NaOH = NaCl + H2O2
I took the spent etchant and developer and adjusted them to PH7. I let the solution set for about 12 hours and a blue sludge that I believe to be copper hydroxide formed at the bottom of the container, and salt water formed at the top.
I siphoned off most of the water being careful not to disturb the sludge.
I tested the PH of the water and it is still PH7, and is crystal clear.
I have reduced the 3 liters of chemicals down to ~250ml of sludge.
Am I on the right track?
Is the blue sludge copper hydroxide?
EasyPC,
Since I AM a chemist, I though I would take a stab at your question. You are definitely on the right track, and nothing you have done so far is problematic, but I would offer a different strategy:
I would recommend neutralizing the etch solution with baking soda (sodium bicarbonate). It will react with all of the acid and will not become overly basic if you overshoot. Keep adding baking soda in a slurry of water until bubbling ceases, stir it a little more, let it sit for a day, and add some excess baking soda to make sure the reaction is complete. At this point, the solution should consist of a bunch of copper salt and water (you can effectively ignore the peroxide), so you can evaporate most of the water off and be left with just the solids to deal with as waste.
WARNING!!!!!!!! The mixture of baking soda and acid WILL CAUSE VIGOROUS BUBBLING from the release of CO2!!!!! Be sure to wear proper safety gear (at least eye protection, gloves and a long sleeved shirt/long pants--an apron or lab coat would be recommended too just as an additional safety redundancy) and work in a well ventilated area!!! Do NOT add too much bicarbonate at once and be sure to stir the solution well before adding more to ensure that you do not have unreacted bicarbonate that will cause unexpected gas evolution when you add more to the solution. If you do get splatter on your skin, wash the area with water for ~5 minutes to ensure that you don't get any acid burns. (now after all of that warning is done with, I think this is a better and safer method than the NaOH addition since addition of the bicarbonate won't let you add the two solutions together too quickly, avoiding potentially hazardous conditions resulting from overheating of the solution, though the chance of this isn't really that great either. . . . )
Either way, you shouldn't really flush these solutions down the drain! Even the water solution from the top! The water will still contain some quantity of dissolved copper that you don't want to loosely introduce into the environment. Though copper isn't really that environmentally dangerous and you won't really be causing a disturbance if you wash copper carbonate down the sink, it isn't good practice to introduce metallic waste into the environment. If you have a college or high school chemistry teacher you know, or a waste disposal facility near by, call them up and ask what the proper disposal method for your locality is.
Again, small quantities of copper won't be an issue, but if you are going to be doing more than a few boards a year, there could potentially be cumulative issues, so be on the safe side!
As an aside, copper hydroxide is blue, as are most hydrated salts of copper(II) (or green if they aren't blue--if you want me to bust out Tanabe-Sugano diagrams for a more in depth discussion as to why this is the case, I will be happy to do so). If there is a black color, it is likely due to contamination from other materials in the developer solutions you have been using. When I do my etching, the resulting solutions are usually green or blue in color depending on what I have done to them, but I have never seen a black solution using these reagents (HCl, peroxide and sodium bicarb.). The blue sludge you see is most likely indeed copper hydroxide or some other copper salt.
David
PS, I am in the middle of grading papers now, so if this seems a little stream of conscious, it very much is. Feel free to ask for clarification if there is some needed!
Since I AM a chemist, I though I would take a stab at your question. You are definitely on the right track, and nothing you have done so far is problematic, but I would offer a different strategy:
I would recommend neutralizing the etch solution with baking soda (sodium bicarbonate). It will react with all of the acid and will not become overly basic if you overshoot. Keep adding baking soda in a slurry of water until bubbling ceases, stir it a little more, let it sit for a day, and add some excess baking soda to make sure the reaction is complete. At this point, the solution should consist of a bunch of copper salt and water (you can effectively ignore the peroxide), so you can evaporate most of the water off and be left with just the solids to deal with as waste.
WARNING!!!!!!!! The mixture of baking soda and acid WILL CAUSE VIGOROUS BUBBLING from the release of CO2!!!!! Be sure to wear proper safety gear (at least eye protection, gloves and a long sleeved shirt/long pants--an apron or lab coat would be recommended too just as an additional safety redundancy) and work in a well ventilated area!!! Do NOT add too much bicarbonate at once and be sure to stir the solution well before adding more to ensure that you do not have unreacted bicarbonate that will cause unexpected gas evolution when you add more to the solution. If you do get splatter on your skin, wash the area with water for ~5 minutes to ensure that you don't get any acid burns. (now after all of that warning is done with, I think this is a better and safer method than the NaOH addition since addition of the bicarbonate won't let you add the two solutions together too quickly, avoiding potentially hazardous conditions resulting from overheating of the solution, though the chance of this isn't really that great either. . . . )
Either way, you shouldn't really flush these solutions down the drain! Even the water solution from the top! The water will still contain some quantity of dissolved copper that you don't want to loosely introduce into the environment. Though copper isn't really that environmentally dangerous and you won't really be causing a disturbance if you wash copper carbonate down the sink, it isn't good practice to introduce metallic waste into the environment. If you have a college or high school chemistry teacher you know, or a waste disposal facility near by, call them up and ask what the proper disposal method for your locality is.
Again, small quantities of copper won't be an issue, but if you are going to be doing more than a few boards a year, there could potentially be cumulative issues, so be on the safe side!
As an aside, copper hydroxide is blue, as are most hydrated salts of copper(II) (or green if they aren't blue--if you want me to bust out Tanabe-Sugano diagrams for a more in depth discussion as to why this is the case, I will be happy to do so). If there is a black color, it is likely due to contamination from other materials in the developer solutions you have been using. When I do my etching, the resulting solutions are usually green or blue in color depending on what I have done to them, but I have never seen a black solution using these reagents (HCl, peroxide and sodium bicarb.). The blue sludge you see is most likely indeed copper hydroxide or some other copper salt.
David
PS, I am in the middle of grading papers now, so if this seems a little stream of conscious, it very much is. Feel free to ask for clarification if there is some needed!
David,
Thank you for your reply. So give it TUMS
Can you give me a ball park estimate of how much baking soda it will take to neutralize 300ml of etch solution that is comprised of 100ml of 31% Hydrochloric acid and 200ml of 3% Hydrogen peroxide.
My goal was to discard the water, and save the sludge. If the water still has copper, and I can not dispose of it, and now I have added sodium bicarbonate to neutralise the solution, I have increased the volume of the solution. This increases the trips to the facility.
Maybe I'll do what I have been doing, just save the solution, when the gallon jug is full take it to the hazard waste facility as is.
Thanks again for your help.
Thank you for your reply. So give it TUMS
Can you give me a ball park estimate of how much baking soda it will take to neutralize 300ml of etch solution that is comprised of 100ml of 31% Hydrochloric acid and 200ml of 3% Hydrogen peroxide.
My goal was to discard the water, and save the sludge. If the water still has copper, and I can not dispose of it, and now I have added sodium bicarbonate to neutralise the solution, I have increased the volume of the solution. This increases the trips to the facility.
Maybe I'll do what I have been doing, just save the solution, when the gallon jug is full take it to the hazard waste facility as is.
Thanks again for your help.
You can just use straight baking soda if you want, just be careful! I would say a box would be more than enough (plus it is quite cheap). Also, if you have a well ventilated area (like a garage) you can leave the cap off of the jug and let the water evaporate off to minimize volume once it is neutralized.
Alternately, you can just take the jug to the disposal facility and let them deal with it without neutralizing anything!
Just out of curiosity, how long/how many boards have you been using your solutions for? If you keep the solution out of light, it should last for a good long time.
PS Tums is CALCIUM carbonate!
Alternately, you can just take the jug to the disposal facility and let them deal with it without neutralizing anything!
Just out of curiosity, how long/how many boards have you been using your solutions for? If you keep the solution out of light, it should last for a good long time.
PS Tums is CALCIUM carbonate!
I use a bubble etch tank that I made myself, the tank will etch a 6" * 9" board, the tank is only 3/8" thick. I has a volume of 475ml. However by the time you add the pcb holder and the volume that the bubbles displace you only need a max of 300ml of etch solution.
The board will etch in just under 3 minutes using 3% H2O2. I can usually etch 3 to 4 boards depending on the board size, if I leave the air running I can do more. The problem is that if I turn off the air the H2O2 quickly turns to H2O. So I etch a few boards at a time and dispose of the solution in the waste jug.
To answer your question, using HCl and H2O2 maybe 30 boards. Before that I used ferric chloride for years. After using HCl and H2O2 for the first time I gave away all my ferric chloride. No more running to RS, and Fry's to find out they are out of stock, or over paying at the local electronic shop, no more heating the solution, no more stains!
Tums, I know, I was just having some fun, Tums, HCL, stomac acid
The board will etch in just under 3 minutes using 3% H2O2. I can usually etch 3 to 4 boards depending on the board size, if I leave the air running I can do more. The problem is that if I turn off the air the H2O2 quickly turns to H2O. So I etch a few boards at a time and dispose of the solution in the waste jug.
To answer your question, using HCl and H2O2 maybe 30 boards. Before that I used ferric chloride for years. After using HCl and H2O2 for the first time I gave away all my ferric chloride. No more running to RS, and Fry's to find out they are out of stock, or over paying at the local electronic shop, no more heating the solution, no more stains!
Tums, I know, I was just having some fun, Tums, HCL, stomac acid
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