Rust Removal Experiments: Electrolysis

hello I've recently been working on the restoration of an old lathe that restoration project included various methods of removing paint and rust like wire brushing and wire wheeling the use of a needle scaler or needle gun sandblasting and more and if you're interested in that restoration project or if you want to know more about those methods you can find a link to the playlist in the video description all of these methods are effective but abrasive or mechanical in nature meaning that they are also quite invasive in this video I will compare different methods of electrochemical and chemical rust removal and my goal is to D rust all the parts that you see here on the bench within a timeframe of 24 hours and yes there is a variety of other chemicals that can be used for this process especially a large number of different assets but this video is just a means to an end because I want to go on with the lathe restoration project and I can't afford to delay that anymore so this has to be quick and that's why I'm using stuff here that I could just grab off the shelf in the next supermarket and what you're going to see here are rust removal experiments with electrolysis cider vinegar citric acid and a commercial product called osteo and please watch the video to the end because there will be a grand before and after comparison of all the parts that you just saw on the bench and I will also give you some numbers on the concentrations that are used as well as some warnings which you absolutely have to follow because there are numerous dangers in the experiments that I am performing here today and I also bought some molasses and that will arrive here tomorrow I will then use that for another rust removal experiment but that will take a much longer time than I have here so the video about that will come up at some point in the future so let's start with the electrolysis experiment and the first thing that I need is a sacrificial anode for this we can just use an old steel plate like this one now this is pretty rusty and that wouldn't be a problem since this thing is going to rust even more when the experiment is done but the thing is that I want to have a relatively high conductivity of the surface to allow for higher currents to pass through the tank and that is why I first use my large angle grinder to rust the surface of this anode and I also attach a steel angle plate to the backside of the anode and this will enable me to hang the electrode on the wall of a plastic tank that I'm going to use for the experiment I also attach a nut on the backside of the electrode and that will keep a distance between the conductive surface and the plastic surface of the tank and this will enable me to practically double the effective conductive cross-section area of the electrode and I drill a 10 millimeter hole at the upper end of the electrode and here a bolt will sit that will connect a wire coming from the current source to the electrode and next I drilled two smaller holes through the electrode and prepare this 0.05 ohms power resistor here with two thick pieces of copper wire and then I attach the resistor electrically to the bolt and also physically to the surface of the electrode which will also act as a heat sink normally I would also add some thermal compound but I just can't find it at the moment and we will use this resistor at least for a short time to measure the current that will be flowing through the electrode by means of the voltage drop that will occur across the power resistor and as a last step I degrees the electrode with some universal thinner before we use it for the experiment the work pieces namely the sex head and a cast-iron hand wheel are prepared for the experiment as well I remove the really loose rust with a wire brush first and then I degrees these parts with the means of some gasoline inside this plastic tank here now I don't recommend doing this this way because well you will inhale some of the fumes also of course there's a fire hazard here so maybe use another chemical or do it outside at least right in front of an opened window I guess and now we need a tank made of a non conductive material I will use this plastic box here and I fill it up with 12 litres of lukewarm water that's around three gallons of water and I can now insert the anode inside the tank and here is my workpiece in this case the X hat that I clamped into this screw clamp and this is how I'm going to do it I lean it against the electrode so that the workpiece and the anode are comparatively close together now often you just use a piece of wood that you place on top of the tank and then you can suspend your work pieces on iron or steel wire dangling from that piece of wood and you can find that in a couple of other videos about this topic that I will link in the video description but I am just going to do it this way now I will add some sodium carbonate usually sold under the name washing soda in supermarkets in Germany we call this not vom carbonate it is added to increase the conductivity of the tap water and here is a warning that you will hear in many videos about this topic use washing soda not baking soda which is not sodium carbonate but sodium hydro carbonate often called by its more old-fashioned but chemically incorrect name sodium bicarbonate now you can make washing soda from baking soda by cooking it but that is a process that you would have to go through before using it for electrolysis and I start with a mixture of 1 tablespoon or washing soda to each gallon of water which is roughly 3.8 liters and I simply took this recipe from the wood magazines video about this which I also linked in the video description and now that I'm added let me warn you about some other dangers as well and that is never to use stainless steel as a material for the anode because there is a danger of you producing hexavalent chromium the electrolysis process which is a highly carcinogenic material you also shouldn't have copper parts for example from your copper wires dangling directly into the tank and you also have to have good ventilation because during the electrolysis process hydrogen is going to be released from the tank and there could be a explosion hazard if that collects inside the room you're working in now you need a current source the plus pole of which is to be connected to the sacrificial anode while the minus pole is to be connected to the workpiece in many other videos you will see that people often utilize car battery chargers for this you could also use an ATX power supply with similar results but I'm going to use this manual metal arc welding machine here often called a stick welder and of course it has to be a DC stick welder most experiments that I have seen on YouTube so far use comparatively low currents between 1 and maybe 10 amps why we will go much higher here and start with 10 MS and go up from that value so the DMM displays the voltage drop across a 0.05 ohms resistor that means that you have to read off the voltage reading in volts multiply it by 20 and divide it by 1 ohms to get the current reading in amp ere's or in other words multiply it with 20 and thing in your head that it's amps not volts okay so we're at the absolute minimum value and if you multiply zero point four five or four four times 20 you get zero point nine nine and pair so we are around ten amps when this potentiometer here is down to the absolute minimum value and we can already see a rather violent reaction here on the sacrificial anode let's see what happens if I crank up the supply voltage so that we will have a larger current flowing through the bath we are now at around 20 amps pretty wild huh and let's crank up the supply voltage even more so one point six volts if you multiply that by 20 you are at 32 amps and that is the maximum that I can get here no matter how much I crank up that is of course because the welding machine is designed in such a way for safety purposes that a certain voltage between the two electrodes cannot be exceeded and it can deliver 150 amps but only if the conductance between the two electrodes is high enough or the resistance is low enough in other words and that means that if you want to reach even higher currents we have to separate the water with more sodium carbonate and even though I'm standing right next to the opened window I have a better feeling about this if we go on the balcony and proceed with the experiment there so we're now on the balcony and the current is around 30 m/s I will now switch off the Machine put another tablespoon of sodium carbonate into the mixture stir it a little bit and reactivate the welding machine and here you can see that we're now talking about 2 volts voltage drop which equates to around 40 m/s of current passing through the electrolysis tank and P equals I squared times R which means that the power dissipation inside the power resistor alone is at this point at around 80 watts which far exceeds its power rating and that is what we can only do this for a couple of seconds and here you already see black smoke coming from the resistor and that is why I will now connect the clamp directly to the 10 millimeter screw not using the power resistor any longer and after only 10 minutes of electrolysis with a current value of around 40 ms I took out the ex-head wash it here with a brush and some soapy water and then dried it with a towel just to check how far the process had held at this point in time and as you can see a lot of the rust had already vanished but I put it back into the electrolysis tank and let the process go on for up to eight hours and I checked every half hour or so for the progress and it became obvious that most of the rust had gone after just one hour of electrolysis and the seven hours that I put on top of that were basically not necessary and after that I took out the ex-head I cleaned it off with some steel wool dried it with a piece of cotton and then I altered with some bells toll and that is what it now looks like and after I had tried it on this forged axe head I you purposely used a cast iron part this cast iron hand wheel here and repeated the process this time I only waited about four hours and after that I used a wire brush to clean off the material and here's a little before and after a comparison of the electrolysis process first the ex-head made of forged steel I guess from around the middle of the 20th century treated at 40 amps for about eight hours and here is a cast iron hand wheel and you affected around the turn of the century and it was inside the tank for four hours at again around 40 ms of current so as I said in the beginning of the video I actually originally intended to show you the results of all my rust removal experiments within this episode but editing the electrolysis experiment just took me longer than expected and I can't find the time today to do all the rest of the work but I do promise you that a second part of this video will go online until Thursday so I hope you like this and see you soon

Channel: The Post Apocalyptic Inventor

Views: 561,408

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Id: HN590K81D5c

Length: 14min 19sec (859 seconds)

Published: Mon May 09 2016