philb Posted January 24, 2012 Share Posted January 24, 2012 Background: The rear springs on my Matador have rusted so badly between the leaves that they have burst the clamps and buckled the upper leaves. They could possibly be given a new lease of life but the prospect is not good. A bit of luck: I was able to buy another pair of springs from a chap nearby, in much better condition but, having been laid on their side in a field for many years, were still pretty rusty and I don't want them ending up the same state as the current pair. I'm sure grit blasting would have cleaned them up but my little compressor wasn't up to it and I don't like to give in straight away to getting someone else to do it. Make and mend is all part of the hobby. Testing the enemy: I dismantled the new springs (16 leaves and about 90kg each set) and attacked the rust with the usual DIY tools - angle grinder equipped with wire brush and polycarbide fleece, needle gun, files etc.. Most of the rust seemed to be annoyed by this treatment, it went shiny and gripped tight. A cunning plan: I'd heard about the use of electrolysis to remove rust (on this forum and elsewhere) so I read up about it. The process is dead easy to set up - the part to be cleaned is the cathode (-ve), some scrap iron or mild steel (nothing with Chromium in it) is the anode (+ve) and a weak solution washing soda is the electrolyte. They just need to be placed in a watertight container and hooked up to a low voltage DC supply. It's safe process (as long as the hydrogen that can be released is allowed to blow away in the wind) but it can result in embrittlement of high carbon steels (like springs!) if precautions aren't taken. Into battle: I made a spring sized (60 inches long) wooden trough from some scrap and lined it with a bit of redundant pond liner. I welded a few bit of scrap steel together to make two anodes (to connect together and place either side of the part being cleaned) and welded some long nails to them with bolts on the end of the nails to make electrical connections above the electrolyte level. Then used a lap-top power supply (a battery charger, but not a modern clever one, would do) with a current limiting resistor to supply the juice. Victory! (provisional - until I've fitted them and driven a few thousand miles): Well what do you know, it seems to work a treat. I set the current very low (about 1 Amp for the big leaves, ~4mA per square inch - to minimise the gassing and the likelihood of atomic hydrogen migrating into the steel grain structure and stressing it) and left each leaf in the trough for a day. After that. most of the rust just washes off and a quick buzz with the wire brush reveals clean shiny steel. If doesn't fill the pits but gets right to the root of them - nothing I know of except blasting would do that. Evidence: If I've got the hang of the process, the first pic shows, from right to left, a typical leaf before treatment, after electrolysis and wire brushing, a squirt of "metal ready" and a coat of Owatrol preserver ready for assembly and painting. the second pic is work in progress and the third pic is the trough with one of the last leaves in it. Voila! Quote Link to comment Share on other sites More sharing options...
philb Posted January 24, 2012 Author Share Posted January 24, 2012 So, the pics are in reverse order, I'll stick to cleaning. Quote Link to comment Share on other sites More sharing options...
Zero-Five-Two Posted January 24, 2012 Share Posted January 24, 2012 Seems to work very well for a homemade invention,nice idea Quote Link to comment Share on other sites More sharing options...
timbo Posted January 24, 2012 Share Posted January 24, 2012 Nice post looks impressive in the face of it... Now, where can i find a vessel big enough to get an entire land rover into...?! Quote Link to comment Share on other sites More sharing options...
Essex5 Posted January 24, 2012 Share Posted January 24, 2012 Now, where can i find a vessel big enough to get an entire land rover into...?! I bet you're not using the swimming pool in this weather........? John Quote Link to comment Share on other sites More sharing options...
philb Posted January 25, 2012 Author Share Posted January 25, 2012 Now, where can i find a vessel big enough to get an entire land rover into...?! Not so daft as it sounds - the Navy use the same scheme, but with Sodium Chloride mostly, to stop their submarines from rusting. I know, that's not quite what it's for but the electro-chemistry is the same. You don't have to treat the whole thing at the same time. There are lots of folk who have partly submerged awkward shapes and made special anodes that fit inside hollow sections and gradually treated the whole area. If there are exposed patches of rust you don't even need to immerse them. Use a wad of rag or old carpet felt soaked in the electrolyte solution and press it against the area to be treated with a steel plate, the anode. I'm not on commission, honest, just a bit excited to find something that works for once. Quote Link to comment Share on other sites More sharing options...
scammell 7377 Posted January 25, 2012 Share Posted January 25, 2012 so if ive got this right, do you connect the neg to the rusty item and the live to a lump of scrap steel imerse it all but make sure the pos and item to be cleaned dont toutch ? i have chargers of differing voltages any one better than another one Quote Link to comment Share on other sites More sharing options...
mash Posted January 25, 2012 Share Posted January 25, 2012 Nice post looks impressive in the face of it... Now, where can i find a vessel big enough to get an entire land rover into...?! A perfect excuse to buy an lovely IMMLC or the MMLC..... hmmmmmmmmm Quote Link to comment Share on other sites More sharing options...
philb Posted January 25, 2012 Author Share Posted January 25, 2012 so if ive got this right, do you connect the neg to the rusty item and the live to a lump of scrap steel imerse it all but make sure the pos and item to be cleaned dont toutch ? i have chargers of differing voltages any one better than another one Yes, that's the right way round. If you are cleaning low carbon steel or iron parts you can do it as quickly as you like by using large area anodes and high current (I've seen one chap who uses a DC welder at 30 amps to clean big generator housings in a few hours). the voltage you need to get this depends on the resistance between the electrodes, which depends mainly on the geometry of the set-up. 12 volts would probably do nicely for odd jobs. If you are cleaning high carbon steel that will be highly stressed in use, you must either prevent excessive hydrogen formation at the cathode (work piece) by using very low current densities (implies low voltages) and taking a long time over it or bake the work piece at 200C for an hour or two immediately after electrolysis to drive out any free hydrogen atoms from the steel surface. Parts are quite clean after electrolysis and a quick wire brushing so you might get away with popping them in the kitchen oven late at night without raising suspicion. (If you get caught, it wasn't me who told you to do it!) Have a look on U-Tube to see many good examples, and some nutters (it's fairly obvious). Quote Link to comment Share on other sites More sharing options...
scammell 7377 Posted January 27, 2012 Share Posted January 27, 2012 thanks i can see me trying this at some point although im told kitchen not an option Quote Link to comment Share on other sites More sharing options...
Tony B Posted January 27, 2012 Share Posted January 27, 2012 What sort of 12 volt supply do you need? And importantly the ampage? Quote Link to comment Share on other sites More sharing options...
gritineye Posted January 27, 2012 Share Posted January 27, 2012 I can confirm this really does work a treat, it's one of the most satisfyingly simple things to do...makes you feel very clever too! Quote Link to comment Share on other sites More sharing options...
Tony B Posted January 27, 2012 Share Posted January 27, 2012 Igorrrr! Raise the lightning rod! Haha haaha haaaaha. Going to try it something small tommorow. Quote Link to comment Share on other sites More sharing options...
gritineye Posted January 27, 2012 Share Posted January 27, 2012 I use a battery charger with a bulb in the live wire to reduce it a bit, not good with the technical stuff but it worked well for me! Quote Link to comment Share on other sites More sharing options...
Tony B Posted January 27, 2012 Share Posted January 27, 2012 I've an old charger, I'll stick a 21 watt bulb in series that should giove about 75 ohm. Got some rusty old shackles to try out on. Quote Link to comment Share on other sites More sharing options...
LongJohn Posted January 27, 2012 Share Posted January 27, 2012 A battery charger putting out around 8 amps or so is ample, last year I was restoring an old Honda motorcycle and the tank was extremely rusty inside. Electrolysis worked extremely well for me and as a bonus it is very cheap to do! Washing soda is available at most of the major supermarkets at about a pound a packet, I forget the brand name but it will be buried amongst the laundry powder section somewhere. There are several clips on youtube to peruse and this is one of them: Quote Link to comment Share on other sites More sharing options...
Rangie Posted January 27, 2012 Share Posted January 27, 2012 I've used electrolysis with great success for years! Just remember for best results to change the solution for each batch of parts, as it eventually gets spent. Also, give the anodes a clean before each use to remove the grotty oxide residues. The anodes eventually get eaten away but it does depend on how rusty the part is/how many amps you are pumping in etc. Be careful with aluminium as it can be vicious with it. I have removed an aluminium piston from a pump by using a salt solution instead of a caustic solution, it ate it away sufficiently to get the damned thing out!! :nut: Or you could try the age-old american way of submerging ferrous parts in farm treacle or molasses, leave them in a few months and it cleans them up nicely! Alec. Quote Link to comment Share on other sites More sharing options...
Tony B Posted January 28, 2012 Share Posted January 28, 2012 Don't forget the other Good 'Ole US rust remover Coca Cola! :-D Quote Link to comment Share on other sites More sharing options...
REG Posted January 28, 2012 Share Posted January 28, 2012 Molasses!!! Thinking about filling up some old Jerry Cans to clean them out. I was looking at the electrolisis approach but fancy diluted molasses! Is this the same as the coke method? Quote Link to comment Share on other sites More sharing options...
Tony B Posted January 28, 2012 Share Posted January 28, 2012 Molasses!!! Thinking about filling up some old Jerry Cans to clean them out. I was looking at the electrolisis approach but fancy diluted molasses! Is this the same as the coke method? Has its dangers! http://en.wikipedia.org/wiki/Boston_Molasses_Disaster :shocked: Quote Link to comment Share on other sites More sharing options...
pc1959 Posted January 28, 2012 Share Posted January 28, 2012 (edited) I use a battery charger with a bulb in the live wire to reduce it a bit, not good with the technical stuff but it worked well for me! That's exactly what I did as well! I used a v. small bulb from a dashboard light (5w) and an old battery charger, left the stuff in the tank for a few days and have had a lot of success with the method. Another benefit is that it seems to unsieze rusted nuts and bolts, I had some mud flap brackets with M5 studs on them which just snapped off when I tried to remove the nuts. After a bit of electrolysis they undid without problems. There's a good explanation of how it works http://myweb.tiscali.co.uk/andyspatch/rust.htm Edited January 28, 2012 by pc1959 Quote Link to comment Share on other sites More sharing options...
Jessie The Jeep Posted January 28, 2012 Share Posted January 28, 2012 What product should I be looking for, for sodium carbonate? Lynne had a look in Asda this morning, but couldn't find anything. Quote Link to comment Share on other sites More sharing options...
Tony B Posted January 28, 2012 Share Posted January 28, 2012 What product should I be looking for, for sodium carbonate? Lynne had a look in Asda this morning, but couldn't find anything. Commonly sold as 'Washing Soda'. Check ingredients. Quote Link to comment Share on other sites More sharing options...
Kufra Kiwi Posted January 28, 2012 Share Posted January 28, 2012 Anyone had any experience removing the rust from a petrol tank by electrolysis? The petrol tank from our 1942 Chev truck is rusted inside and out. I have previously had good success with mollasses but for obvious reasons I don't want to introduce any kind of sugar into a petrol tank. I think with electrolysis the main difficulty would be getting a large enough anode inside the tank (and then out again) through the narrow filler neck? Quote Link to comment Share on other sites More sharing options...
Zero-Five-Two Posted January 28, 2012 Share Posted January 28, 2012 What product should I be looking for, for sodium carbonate? Lynne had a look in Asda this morning, but couldn't find anything. Plenty on Evilbay, for only a couple of quid a box Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.