I don't see why the process has to take days, unless there are specific reasons for this.
It's just become generally accepted practice for co-dep experiments- but you may be right. Also meetings and other nonsense means I an not able to go to the lab every day, so sometimes experiments have to wait for me, rather than the other way around.
There must be some underlying reason for that, though. Perhaps that's from Pd-D experiments (with which co-deposition experiments have been traditionally made) where one might want to be extra careful not to waste the reagents.
Otherwise, even dendritic deposition—which sometimes has been linked with LENR—appears to occur easily if current is increased a bit too much (some can be seen in the previously posted photo for the copper piece with extra Fe deposition).
The Fe deposition layer on same copper piece, by the way, is still shiny and hasn't dulled yet.
The cathode has a good coat of iron, overlaid with loosely adhered black iron oxide...
Looks like this test was a success. Tomorrow I'll test for the LEC effect.
Very nice job! 
Please take into account that the iron layer oxidizes at a very fast rate if left in air, and the LEC effect decreases over time about at the same rate. So will tomorrow be too late? Finger crossed... 
I have been playing around with the FeCl2 solution made by dissolving some steel wool in 10% HCl, and it seems to work well compared to my previous attempts.
Very good looking iron plating! It looks like actual iron. The HCl method gives instead a quite black, less shining coating. This may be due to incorporation of magnetite particles or to a different structure of the lattice.
I should clarify that when I initially used it for the deposition test, the FeCl2 solution still contained free HCl, as I removed the steel wool while it was still evolving hydrogen at a low rate. However, I currently don't have any means to measure the pH, so it's possible that I got lucky with it and accidentally reached the sweet spot for depositing iron.
The anode was a plain steel piece and still got consumed fairly rapidly despite the overall low current compared to my previous turbo-attempts just using HCl. The solution got somewhat above ambient temperature (very mildly warm).
Whether this sort of deposition layer is useful for the LEC effect it's unclear, but Frank Gordon previously reported using a 0.1M FeCl2 solution which could be expected to normally produce a similar Fe deposition layer. I used a much higher current density, however (~0.2A/cm2, just considering the immersed cathode portion facing the counter-electrode). At lower currents just the edges of the copper sheet seemed to receive visible deposition while the face either didn't or got covered very slowly.
Very nice job!
Please take into account that the iron layer oxidizes at a very fast rate if left in air, and the LEC effect decreases over time about at the same rate. So will tomorrow be too late? Finger crossed...
Very good looking iron plating! It looks like actual iron. The HCl method gives instead a quite black, less shining coating. This may be due to incorporation of magnetite particles or to a different structure of the lattice.
Thank you kind sir- aware of the problems so popped it back in the tank with the current turned dow. Incidentally, this was the voltage/current used for the run
This excerpt is from one of the previously posted papers on iron deposition using ferrous chloride solutions. While usually calcium chloride is also used in ferrous chloride plating baths, it seems that if the FeCl2 concentration is high enough, the same can also be used on its own at higher current densities:
On a related note, I made other plating tests after adding diluted 10% HCl but I had overall worse results and couldn't obtain a shiny Fe deposition layer as easily as before—which, again, whether that is actually desired it's unclear.
Display MorePlating trials with 5% HCl are going well.
This was the anode at the start..
.
This was the anode after 72 hours...still there, just.
The cathode has a good coat of iron, overlaid with loosely adhered black iron oxide...
Looks like this test was a success. Tomorrow I'll test for the LEC effect.
Alan Smith - that's very happy news indeed!
Not sure if this is of any help, but I tried again the FeCl2 deposition process to see if I just got lucky earlier on.
I recycled most of the previously used solution, added more 10% HCl and some steel wool. After making the solution digest the wool overnight (outside), the solution looked green/emerald green. Note that contact with air/oxygen makes it slowly turn yellower.
I put the solution in a different jar and used a cleaner Cu piece shaped similar to the one I previously used.
In the new jar with the increased amount of solution the immersed surface was about 14 cm2. The initial attempt was with 0.8–2.0A with voltages < 2V. At 0.8A voltage was 1.25V. It "feels" like initially using a higher current level helps kickstarting the process, but for most of the short period I only used 0.8A. The so-obtained Fe layer was very thin and a magnet could not be attracted to it.
So I restarted it at 2.5A and 2.87V for a current density of about 0.18A/cm2. About 9 minutes later I stopped the process. The Fe layer was thicker and somewhat magnetic but not as much as yesterday where the layer was shiny, possibly due to higher current density and much thicker deposition layer.
The yellow-looking jar contains sodium bicarbonate. I used it to neutralize the electrolyte residues on the piece, which did not oxidize afterward.
Bottom line: the process seems simple to reproduce (it was not just luck) using FeCl2 solution and with higher current densities than suggested so far, although this time I used lower current than yesterday.
Your mileage may vary.
EDIT: I also took the chance to coat some more yesterday's graphite rod, although I couldn't manage to obtain the same thick and bright layer as yesterday. It was still fairly thick and magnetic, though:
Using higher current densities resulted in a pitted and bumpy surface, as in this close-up of Fe on steel blade (which previously had electroless Cu deposition on it). So, something changed although I'm not sure what exactly. It could be the pH or the concentration of FeCl2 in the solution (possibly it was lower this time).
I have to point out again that these deposition attempts are all relatively fast (tens of minutes at most). Also, no visible oxidation within short periods after neutralization with sodium bicarbonate.
Also, no visible oxidation within short periods after neutralization with sodium bicarbonate.
That is the reason I have favoured alkaline electrolytes, which also seem to inhibit the kind of rapis corrosion you get with acid ones.
If rinsing in diluted sodium bicarbonate can solve the oxidation issue and is not a problem for the LEC reaction, it should make the overall process simpler and less error-prone, since the plating solution is easy to make in various ways (for example it should be possible to make it from FeCl3 etchant) and the reagents commonly available.
What I did was just immersing the piece in sodium bicarbonate solution right away after taking it off the FeCl2 bath, agitating it a bit in the solution, and then drying it with paper towel.
As for actual testing in a LEC cell, I'll leave that to others with a more reliable setup.
EDIT: as a side note, the Fe-deposited pieces are still looking good.
EDIT2 : regarding oxidation, a related statement from one of the documents I previously linked on Fe deposition:
Just for the record: after a few hours in the atmosphere the graphite rod which was electrodeposited with Fe at moderately high current has developed dark round spots which don't look like oxidation nor due to material peeling off. The area shown in this photo corresponds roughly to the visible area in the previously posted one (the red-tinted area is a reflection from the copper piece nearby).
The copper piece with Fe deposited at low-ish current and the Cu-Fe blade with Fe deposited at high current still look unchanged.
EDIT 2021-11-14 : perhaps it's oxidation from trapped electrolyte residues, after all. It got worse overnight. The other pieces look still good.
Earlier on in this thread I mentioned that crackling sound could be heard occasionally under certain conditions after depositing Fe; this time I have a recording.
Here Fe-C was electrodeposited from a FeCl2 solution (concentration and pH unknown, but I think the pH increased to the point that fine steel filaments wouldn't generate much gas) with the addition of slight amounts of citric acid, using moderately high current of 3.0A on the roughly 14 cm2 copper piece. The audio actually is after neutralization of electrolyte residues and drying, while the video (looping a few times) is from a couple minutes earlier.
The crackling sounds have been digitally amplified and they are strongly audible as I put the microphone of my cellphone on top of the long copper piece resting on an empty glass jar. Since supposedly Fe-C is harder than just Fe, possibly this makes the effect more easily observed. In general, according to the literature adding soluble organic compounds (even sugar) to the solution should cause the co-deposition of carbon on the piece; see this example from the paper I linked several times in the past few posts:
The idea of adding citric acid was mainly to see if I could tweak the pH without using more HCl, but it failed in this regard. Overall the visual quality of the deposition layer was lower and I couldn't obtain anymore a bright/shiny layer as before, so probably I ruined the FeCl2 solution. The deposition layer tends to turn dark (possibly more similar to that shown by others) but it still does not oxidize thanks to neutralization in sodium bicarbonate. I don't think it's magnetite. The photo below is from a different Cu piece.
At higher current it tends to acquire a "burned" appearance, while it's smoother at lower currents, with much less chance of generating this sound effect (it still does to some extent). It looks like excess hydrogen is needed, although at all times in my case fine bubbles were generates at both electrodes, and at higher temperatures and/or current levels, a slight fine mist too from the cathode.
EDIT: several hours later, the above black-coated piece still emits the same noise at a rather low rate.
Earlier on in this thread I mentioned that crackling sound could be heard occasionally under certain conditions after depositing Fe; this time I have a recording.
Here Fe-C was electrodeposited from a FeCl2 solution (concentration and pH unknown, but I think the pH increased to the point that fine steel filaments wouldn't generate much gas) with the addition of slight amounts of citric acid, using moderately high current of 3.0A on the roughly 14 cm2 copper piece. The audio actually is after neutralization of electrolyte residues and drying, while the video (looping a few times) is from a couple minutes earlier.
There are what appear to be some linear light tracks as well as the many small flashes visible in the video. These are relatively quick, lasting one video frame or less, unlike the persistent bright spots that are probably bubbles on the surface. Some of the short-live ones may also be reflections from evolved gas, assuming the video was done during the plating. Have you looked in the dark to see if any light is actually coming from the surface chemistry?
Wonder if the surface chemistry can be stimulated to high voltage using it own voltage.
Earlier on, when the pH was likely much lower (I had removed the steel wool from the emerald-green solution while it was still visibly outgassing) and the iron deposition layer was bright and effortlessly accomplished, in one of the tests at higher current levels I saw low-temperature flashes in the plating solution, but these could have come from the tips of dendritic deposits formed in real-time.
However, I haven't actually seen bright/white flashes from the surface of the smoother as-deposited Fe-C piece visible here and so I haven't tried looking for them in the dark.
The video above was made immediately after taking the piece out of the plating bath (before neutralization in sodium bicarbonate) because I was curious seeing if anything in particular could be observed due to this crackling sound. I figured that if noises strong enough to cause the piece to resonate were generated, they might actually manifest themselves in some other way (more mundane effects like small pieces of metal getting ejected, tracks due to pressurized gas, etc).
Occasionally louder crackling noises could be heard during the plating process but I haven't checked the surface for flashes. When I put the piece in the sodium bicarbonate solution there appeared to be a large amount of gas evolution and generation of crackling noises also, but I haven't recorded that and I didn't notice flashes there either.
As a side note, after more than 12 hours the solution has turned yellowish (olive oil color), so I don't expect it to be good according to what is mentioned in the literature. This could be from the too high pH unable to dissolve fast enough a steel piece I put there to keep the solution "reduced" (as FeCl2). Also, there are many floating non-magnetic residues which are likely to be harmful for the plating process.
EDIT: the Fe-deposited Cu pieces still emit crackling sounds at a low rate.
EDIT: after filtering (no change except for the floating residues) and adding more 10% HCl (I'm almost out of it; I should consider getting >30% HCl):
When I put the piece in the sodium bicarbonate solution there appeared to be a large amount of gas evolution and generation of crackling noises
This is probably CO2 from the reaction between HCl and NaHCO3. The crackling at this stage might be cause by the same reaction going on in acid solution present between less than perfectly adhered plating and the substrate.
I meant that there seemed to be a larger generation of gas than just CO2 from the reaction between HCl and NaHCO3.
In any case, it is still doing it, albeit not at the same intensity as before. I just tried immersing the Fe-deposited pieces in warm tap water and recording the effect. At minute 0:30 I put the camera microphone on top of the jar. The audio has been amplified for clarity:
EDIT: After immersion in tap water and drying with paper towel, the pieces, which remained black until earlier, have started oxidizing a bit.
... Have you looked in the dark to see if any light is actually coming from the surface chemistry?
Good idea. This seems easy to do. What say you can?
Video or photo or both. 
I could try again with the remaining FeCl2 solution (I need high concentration HCl to decrease the pH without diluting the solution further) but I don't expect to see visible light. If there were flashes in the video, they were likely reflections from the relatively strong cell phone LED I used for lighting the piece up.
In principle, if there was a large amount of energetic/excited H coming out of the piece, there might be visible light emission e.g. from the known Balmer lines. I don't think this would cause bright flashes however.
EDIT: from an initial test with the plating solution with probably lower pH than yesterday, I am now obtaining a smoother gray layer (still rather thin), but it does not seem to be outgassing significantly. I wonder if that was mainly due to higher pH, which according to the literature may "increase stresses" in the deposits.
EDIT: I added some amounts of citric acid (organic compound) and eventually the deposition layer turned darker, but not as rough and noisy as yesterday. So there must be something else for that; I'm suspecting pH should be higher (otherwise, I have no idea EDIT: besides that a thicker deposition layer might be needed).
EDIT: unfortunately it's not working as intended anymore; probably I ruined my FeCl2 solution by adding too much citric acid. I should start over again with new FeCl2 solution, when I'll get new HCl.
It seems like doing these sorts of electrodeposition tests also deposits microscopic staining droplets all over the place. So be prepared to clean a lot, or to use a fume hood.
