Maverik Posted September 25, 2014 Share Posted September 25, 2014 Now I've been thinking about this for a while and I'll give it a shot but not quite worked out where I want to bolt some... ( I was thinking some strips/bar bolted to the steel frame of my rear door...) I digress has anyone else ever considered such things... with particular regard to stopping the Alu door skins from disappearing... Anyone anything to add? Mav Quote Link to comment Share on other sites More sharing options...
Snagger Posted September 25, 2014 Share Posted September 25, 2014 A galvanised door frame will work in much the same way as the zinc is sacrificial to the aluminium. Magnesium might not be a good idea in practice, though: it's a wee bit reactive! The best thing to do is remove the skin, clean up the frame and paint it with red lead or zinc rich primer, use duct tape over the steel that will be in contact with the aluminium and then refit the skin before painting. I used seam sealer in place of the tape when I built my front doors, and while it has worked perfectly and preserved the aluminium without a single fault, it was difficult to fit the skins because of the resistance of the seam sealer - tape is thin and even but 100% electrically inhibiting. Quote Link to comment Share on other sites More sharing options...
landroversforever Posted September 25, 2014 Share Posted September 25, 2014 Just bolting something to it will I believe only work if the item is submerged. It needs something to keep the metals separated. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted September 25, 2014 Share Posted September 25, 2014 I was thinking of welding a zinc anode to the chassis, when I'm repairing it. Can't hurt. They're on ebay. G. Quote Link to comment Share on other sites More sharing options...
Shackleton Posted September 25, 2014 Share Posted September 25, 2014 agree with snagger. the metals need to be separated. working on yachts Ive usedd thin plastic and a speccialist isolating compound called tef gel , which is intended for bolt threads and other metal fastenings, say a stainless bolt fixed to aluminium Quote Link to comment Share on other sites More sharing options...
ejparrott Posted September 25, 2014 Share Posted September 25, 2014 I don't think it will work unless you leave the land rover permanently submerged in water. My understanding is that is how they work. They are always welded to narrowboats in areas of he hull that never come above water. Quote Link to comment Share on other sites More sharing options...
HampshireHog Posted September 25, 2014 Share Posted September 25, 2014 Wasn't there an Aussie firm selling something along these lines ? Quote Link to comment Share on other sites More sharing options...
sean f Posted September 25, 2014 Share Posted September 25, 2014 As others have said it won't work unless you store the vehicle under water. For it to be a sacricial anode the electrolyte I.e. water needs to be in contact with the anode and part they are to protect then the anode corrodes first. If the car is very very wet it might just work but most of the time it won't. Quote Link to comment Share on other sites More sharing options...
JeffR Posted September 25, 2014 Share Posted September 25, 2014 Just bolting something to it will I believe only work if the item is submerged. It needs something to keep the metals separated. It's a Landrover, it's gonna get wet inside when it rains, come to think of it, it's gonna get wet inside the the humidity is high........ Quote Link to comment Share on other sites More sharing options...
Boydie Posted September 26, 2014 Share Posted September 26, 2014 Just a thought, save your money and buy a pressure cleaner and wash down, and I mean really wash down your landy after your weekend jaunt or once every two weeks in winter if you have to drive on roads that have had salt sprayed on them to disolve snow and frost. We dont have the corrosion problems here in Australia that you have in the UK, even so after every trip I make into the red interior I remove the inner door panels (trim) and wash all the dust and accumulated crud from their insides, the next operation is to flush out the chassis rails, before the trip I tape up all the openings which makes this oiperation easier, all that remains is to clean the underside before the end of trip spanner check. The second best thing I ever purchased was a full one piece water proof overall that allows me to do this without getting soaking wet. Quote Link to comment Share on other sites More sharing options...
cackshifter Posted September 26, 2014 Share Posted September 26, 2014 The problem is (and you probably aren't suffering this) if the roads are salted it's probably cold; so using a jet wash is right out because of the ice hazard. You have to wait till we get an Atlantic low and it warms up and rains, and that can take weeks. Also someone has to ask, Ok, what was the best thing you bought then? Quote Link to comment Share on other sites More sharing options...
zim Posted September 26, 2014 Share Posted September 26, 2014 You been looking at the legs on a jackup ? Quote Link to comment Share on other sites More sharing options...
sean f Posted September 26, 2014 Share Posted September 26, 2014 As it happens yes!. View out my cabin window is the 520ft marker on the leg of the E120, nice shiny new build jack up. Quote Link to comment Share on other sites More sharing options...
Shackleton Posted September 27, 2014 Share Posted September 27, 2014 I remove the inner door panels (trim) and wash all the dust and accumulated crud from their insides Pity you weren't the owner of my D2. It came from Australia. If I lift carpets, take an outer panel off or an interior one for that matter, everything's covered in red dust. It just goes to show how far dust/salt/particles can penetrate. Quote Link to comment Share on other sites More sharing options...
zim Posted September 27, 2014 Share Posted September 27, 2014 As it happens yes!. View out my cabin window is the 520ft marker on the leg of the E120, nice shiny new build jack up. I'm currently flying home after a 3 week rig move.... Sick of jacking up n down. Took shelter for a week in safe waters due to weather. 31 days on board is enough ! Quote Link to comment Share on other sites More sharing options...
Boydie Posted September 27, 2014 Share Posted September 27, 2014 LOL, the best thing I ever bought, -- top cover health insurance in 2006 - just before I needed a quadrouple heart by-pass -- pity it didnt prevent me contracting MRSA never mind, I survived and in my hospital bed decided to have a change of life, unfortunatly this also included a change of wife, so I did some research and purchased a low milage 2.5L 300TDi Disco and to date Julie and I have covered a tad over 250,000 kilometers out in the Australian bush and fully expect to cover at least a million more before I give it away and settle down. Quote Link to comment Share on other sites More sharing options...
robertspark Posted September 27, 2014 Share Posted September 27, 2014 2p... I thought about getting a magnesium rod and making some washers and bolting them where required with a few additional self tappers (mild steel not S/S!!!) http://www.ebay.co.uk/itm/Magnesium-Rods-15mm-x-95mm-99-95-Metal-Sticks-Blocks-Bars-UK-/171259190301?pt=UK_BOI_Medical_Lab_Equipment_Lab_Supplies_ET&var=&hash=item27dfd7dc1d Seems all the research I have done on the matter either goes one of two ways: 1) magnesium is reactive and can be highly flammable when a source of ignition is about (it does not seem to self combust just sat on a table / chassis / door, but has an auto ignition temperature of around 473ºC), and there is a whole group of people who seem to be really adamant don't do it on the grounds of combustion / furiocity of combustion of magnesium. 2) contact area surface to surface contact. The problem with a sacrificial anode is that it is reliant upon contact area, on a boat they are immersed in water so the contact is very good because of the ions in the water. In a landrover they are reliant upon metal to metal contact. but when the magnesium anode corrodes the contact path reduces, given it corrodes at the point of metal to metal contact..... meaning it will work for a short while then not so well. The other thing is they only work over a certain coverage area so you need to have quite a few and space them accordingly (never seen a calculation for the required spacing). My thoughts on washers were it's easy to get some magnesium rods, drill a hole in the center (well lubed / slowly) and them part them off on the lathe as washers, fix as required. All information seems to point to the use of zinc (galv or painted) was it's got the best contact path + cheap + non-reactive (combustible) Not tried the magnesium anode though, but still pondering the thought Quote Link to comment Share on other sites More sharing options...
Boydie Posted September 27, 2014 Share Posted September 27, 2014 Shackleton, you are so right, which isone of the reasons why I spend up to two days just de-dusting the Disco after a desert trip, the interior gets stripped out (very easy as its been cut around the centre console) , the remaining two seats get hosed through and the interior subjected to a high pressure air blast while a cooling fan is blowing ---- then I get atarted on the underside and engine bay, just as well Julie likes the red sand in the driveway !!!! Even so my message is simple, in my 'umble opinion water, on its own is seldom a problem, mixed with salts and crud - different matter, salts help it form an alkali and crud turns into a mud which holds the moisture onto the metal surface, again the simple cure is to wash it down. Quote Link to comment Share on other sites More sharing options...
Maverik Posted September 27, 2014 Author Share Posted September 27, 2014 So.... tell me why do aluminium door skins oxidise like they do... they are not submerged in water all the time...? If I attach magnesium to the same steel door frame in the same conditions as the aluminum skin, whats going to happen?... Say strips of magnesium fixed to the inner bottom of your doors (usually nice and damp) could forsceably help keep tin/alu worm away a little longer... Quote Link to comment Share on other sites More sharing options...
robertspark Posted September 27, 2014 Share Posted September 27, 2014 So.... tell me why do aluminium door skins oxidise like they do... they are not submerged in water all the time...? If I attach magnesium to the same steel door frame in the same conditions as the aluminum skin, whats going to happen?... Say strips of magnesium fixed to the inner bottom of your doors (usually nice and damp) could forsceably help keep tin/alu worm away a little longer... Contact.... surface area .... conductive ion deposits ..... give it a go with the magnesium washers and tell us how it goes? My 90s still in bits door corrosion is the last thing on my mind at the moment. Quote Link to comment Share on other sites More sharing options...
Soren Frimodt Posted September 28, 2014 Share Posted September 28, 2014 All you need Sir, is some good old Birmabright. Find a nice old S3 88 and swap the body parts with the alterations required Or why not start changing the oxidized Ali with plastic panels? No more corrosion Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted September 28, 2014 Share Posted September 28, 2014 All you need Sir, is some good old Birmabright.........Interesting as Birmabright was a magnesium alloy, apparently equivalent to 5251 which has good corrosion resistance and is recommended for marine environments http://www.smithmetal.com/downloads/5251.pdf why did they change, and what do they use now? Quote Link to comment Share on other sites More sharing options...
mickeyw Posted September 28, 2014 Share Posted September 28, 2014 So.... tell me why do aluminium door skins oxidise like they do... Electrolytic corrosion between two dissmilar metals that are in direct contact. Interesting as Birmabright was a magnesium alloy, apparently equivalent to 5251 which has good corrosion resistance and is recommended for marine environments http://www.smithmetal.com/downloads/5251.pdf why did they change, and what do they use now? Birmabright - a much higher, tough quality grade of alloy than what is used now. Remember this was surplus material for aircraft manufacture! Series panels tended not to corrode anything like those of the coil sprung models. They also were far more resistant to knocks and bumps - they may have been a bit thicker than modern panels, which would have helped too. Bottom line cause of this evil IMO is cost! Quote Link to comment Share on other sites More sharing options...
robertspark Posted September 28, 2014 Share Posted September 28, 2014 Sorry, didn't realise that the question was going towards why aluminium actually corrodes (thought everyone knew who owned a landrover)? As MickeyW stated, galvanic corrosion (potential difference (voltage) between dis-similar metals, naturally inherent in the metals) The greater the potential difference between the metals on the chart below the more likely the active metal will corrode before the noble. hence stainless bolts (A2 most common ( ~ 304s/s)) on aluminium is probably not a good idea (each to their own off topic as the discussion was on anodes), Quote Link to comment Share on other sites More sharing options...
Maverik Posted September 29, 2014 Author Share Posted September 29, 2014 Just a bit of devils advocate... the main question still stands. I've only got one Alu skinned door now and its the rear, will see if I can find some bits of Magnesium and fasten it to the frame see if I get any long term effects. 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.
Note: Your post will require moderator approval before it will be visible.