Two reasons to condition your plates

[Roland Jacques]

Farrah made a post that i believe should have its own thread.

"Under normal conditions the chromium oxide coating on ss is relatively impervious and so protects the underlying metal, but when we are forcing a heavy current through it in an oxygen rich environment such as our electrolysers, then any weaknesses in the surface coating will be exposed and any underlying reactive metal such as iron will of course react.

It is more usual that the anode is attacked this way due to the oxygen being formed, whereas the cathode is often unaffected.

What conditioning does is, by running a steady low current through the cell, weaknesses in this coating are exposed and iron at or near the surface reacts to form rust, which will precipitate into the solution and eventually form a sludge. As there is a lot more chromium in ss that iron, once the iron (or other reactive metal) has reacted and fallen away as an oxide, then more chromuim is exposed and this instantly forms it's protective oxide layer and all is well again. By steadily upping the current through the cell eventually all the iron and any other reactive metals near the surface will have been leached away.

Furthermore, while you are getting the oxygen reacting with such as iron on the electrodes, you will be seeing less oxygen evolved from your cell as gas - it will be busy forming the iron oxide.

Also consider this. Oxide layers are what protect copper and aluminium amongst other metals, and though they are generally insulators, they form such a thin coating that they do not do much to impede current flow. So like our chromium oxide they are relatively porous to tiny electrons. But try forcing too much current through these pores and this is when we start to get trouble as the pores can become holes and, in the case of our ss, expose underlying metals such as iron. So it pays to condition your cells this way initially to avoid the brown sludge and crud you will otherwise get.

This is probably also the main argument for limiting the current density on any electrode - to prevent electrode corrosion.

For a long time people thought it was down to the water being used and inpurities in the water, but in my experience the crud comes primarily from the ss.

Dave Lawton went on to condition his cells further, not to protect them, but to form a mineral layer that upped electrolyser efficiency. He went on to determine efficiencies of 3-4x over-Faraday.

The mineral layer (formed from minerals in 'hard' tap water) forms a coating on the cathode, which I now know allows for plasma discharges within the pores of this mineral coating. Plasma discharges are known to produce more gas from water than Faraday Electrolysis from any given power, but Lawton was achieving this as a by-product of Faraday Electrolysis by pulsing dc.

I've attached a photo of one of my test cells that clearly shows a heavy white mineral coating on the centre ss nut and threaded bar (my cathode). I enhanced Lawtons mineral coating by doping my water with calcium carbonate."
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[Roland Jacques]

The calcium build up is very interesting to me. I assume you could have too much calcium build up. How could I determine when calcium build up becomes too much and becomes counter productive?

Is there a preferred way to build up the calcium layer ?

Ive seen calcium build up on titanium aquarium heaters and glass... I know that exposure of metal to heat, then wetting it (in seawater), then allowing it to a air dry, builds up calcium deposits very fast. It could be made thick as you want it.

[myoldyourgold]

Farrah, in your research of the calcium build up have you discovered the buildup raises or lowers the conductivity of the Stainless? I read somewhere that it lowers the resistance but I have tried to find where that was but seam to have lost it. There is a commercial process for doing something similar which adheres much better and my understanding of it is that they use calcium phosphate. I would like to know if the resulting coating is the same or similar.

[astrocady]

What conditioning does is, by running a steady low current through the cell, weaknesses in this coating are exposed and iron at or near the surface reacts to form rust, which will precipitate into the solution and eventually form a sludge. As there is a lot more chromium in ss that iron, once the iron (or other reactive metal) has reacted and fallen away as an oxide, then more chromuim is exposed and this instantly forms it's protective oxide layer and all is well again. By steadily upping the current through the cell eventually all the iron and any other reactive metals near the surface will have been leached away.

So what parameters do you recommend? What is low and what is high in terms of amps/sq in? Is the progression of amperage increase linear, so do you run a lower amps for, say, 1/2 the cycle and then ramp up during the last half?

Thanks in advance for sharing...
Steve

[Stevo]

I wonder if these parameters (http://www.free-energy-devices.com/f...utting/D14.pdf) would be worth a try even though they may be geared more towards Lawton's replica.

[Farrahday]

So what parameters do you recommend? What is low and what is high in terms of amps/sq in? Is the progression of amperage increase linear, so do you run a lower amps for, say, 1/2 the cycle and then ramp up during the last half?

Thanks in advance for sharing...
Steve

It's not an exact science, as there are numerous things, like plate surface area and indeed current densisty to consider, so everyones cells will be different, but in most cases a couple of amps for a 4 or 5 hours and gradually ramp up the current over the next few days to what you expect to be drawing when in operation. Periodically change the water to so remove any scum and sludge. Eventually the plates do stop leaching reactive metals and the water stays clear.

I couldn't open that link that Stevo has stuck up, but I know what it is and if you can access the link, those guidelines seemed to work very well, but Dave only used relatively low 3- 5 amp current and his conditioning was primarily to form the mineral layer. The process will take longer on heavy current electrolysers. It will be a case of trail and error, just keep cleaning out the water/electrolyte and once the solution stays clear for any given current, up the current level again. Keep doing this a little at a time until the solution is staying clear for long periods at your required current.

This conditioning process appears to effectively give the ss time to self-heal a bit like how the zinc on a galvanised bucket self-heals if scratched - if not form a slighty thicker, more resilient oxide layer.

Drawing too much heavy current too quickly and the chromium doesn't seem to get chance to oxidise and so the protective oxide coating is more fully breached, with the consequences being serious and irreversible corrosion of the ss.

[Stevo]

Drawing too much heavy current too quickly and the chromium doesn't seem to get chance to oxidise and so the protective oxide coating is more fully breached, with the consequences being serious and irreversible corrosion of the ss.

Farrahday,

This makes sense, but let's consider what is being done in terms of plate surface preparation such as sanding, media blasting and other means of increasing surface area which are based on removing minute portions of the plate surface. Seems that regardless of which method was used even these methods would cause serious and irreversible corrosion of the ss. So I wonder how/if providing a calcium layer could possibly stop or slow this condition down. It seems that the calcium layer Roland mentioned would override any chromium oxide layer.

[Farrahday]

Farrahday,

This makes sense, but let's consider what is being done in terms of plate surface preparation such as sanding, media blasting and other means of increasing surface area which are based on removing minute portions of the plate surface. Seems that regardless of which method was used even these methods would cause serious and irreversible corrosion of the ss. So I wonder how/if providing a calcium layer could possibly stop or slow this condition down. It seems that the calcium layer Roland mentioned would override any chromium oxide layer.

Do not get these two conditioning processes confused, they are independent and separate of each other and do not achieve the same thing. For a start it is usually the anode that will corrode more than the cathode, yet it is the cathode that sees the mineral build up as per Lawtons cells. The mineral layer builds up over the existing chromium oxide layer.

Cross hatching, sanding, etc has no ill effects on the stainless steel. No irreversible corrosion is caused by this action. It's not like there is a central iron core or anything, ss is an alloy of various elements mixed throughout its entirety, with iron making up only a very small percentage.

The stainless steel does not have a coating on the surface that once abrasively removed allows the alloy to corrode. Chromium throughout the ss will immediately form a protective oxide layer when exposed to oxygen, either in the air or water. Hence if we scrape off or scratch the protective oxide coating, we are no more exposing reactive metals than would be present at the surface when the ss was first produced. Sure there will be weaknesses in the surface coating just as there was before it was abraded, but the same conditioning process will sort this out.

[Stevo]

Do not get these two conditioning processes confused, they are independent and separate of each other and do not achieve the same thing. For a start it is usually the anode that will corrode more than the cathode, yet it is the cathode that sees the mineral build up as per Lawtons cells. The mineral layer builds up over the existing chromium oxide layer.

Cross hatching, sanding, etc has no ill effects on the stainless steel. No irreversible corrosion is caused by this action. It's not like there is a central iron core or anything, ss is an alloy of various elements mixed throughout its entirety, with iron making up only a very small percentage.

The stainless steel does not have a coating on the surface that once abrasively removed allows the alloy to corrode. Chromium throughout the ss will immediately form a protective oxide layer when exposed to oxygen, either in the air or water. Hence if we scrape off or scratch the protective oxide coating, we are no more exposing reactive metals than would be present at the surface when the ss was first produced. Sure there will be weaknesses in the surface coating just as there was before it was abraded, but the same conditioning process will sort this out.

I'm most certainly not getting these processes confused, but rather trying understand how either cleansing or conditioning can cause the ss to be damaged to the point to where it is "irreversible". I understand ss to be self-healing in a sense. Are you trying to say that somehow there is a way to remove all of the chromium in the ss via conditioning?

btw-

About 3/4 of the way down this page Bob Boyce explains conditioning as a process where low amperage is used just after the cleansing stage where instead NaOH is used at 20% and high amps in order to remove "surface chromium".

http://nicksrealm.com/Forum/viewtopi...=484&start=300

[jwhhopower1978]

sorry littel of topic.. but, is sandning etc worth the effort ?

Sandblasting is easy job but I dont have access..

Fine papper on Air grinders?

I did that last time whit very fine papper (1200k)
but I destroyed my plates before I could test for best mmw
(did a typical newbie mistake )