 | Home > Maintenance & Modifications > Paint adhesion best method - chassis and axles |
 
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| Shroppy Member Since: 25 Feb 2016 Location: Shropshire Posts: 866   
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In my experience there is no substitute for removing all existing coatings / corrosion and applying a high quality paint system to the bare substrate.
The methods I currently use, with good success so far are: - Blast clean, or if not feasible, clean with a series of abrasives. - Clean with panel wipe or isopropyl alcohol - Epoxy prime using 2pack paint system (Jotun Penguard HB) - Topcoat with 2pack polyurethane topcoat (Jotun Hardtop AX) In some cases I will use either phosphoric acid (steel) or an aluminium cleaner to remove oxidation. Just ensure you remove all traces before painting. I use the same process for painting galvanised steel but add the following steps: - Degrease with screwfix degreaser (5l, great stuff) - Abrade surface with red scotchbrite - Degrease 1985 127 V8 Build Thread Series 2 109" Series 1 80" |
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22nd Mar 2022 9:09am |
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| X4SKP Member Since: 29 Nov 2013 Location: Berkshire Posts: 2295 
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Hello Mossberg
You're main observation is correct. Rust is the reaction of the base element iron (Fe) and oxygen (O) with Water acting as a catalyst. To prevent (slow this down) all products and all processes employed aim to break (inhibit) the connection between Fe and O with H2O as the 'link'.... That's it. The Marine world (all Engineering in a Marine environment) probably leads the way. For us land based wanting to do the best, you are right it is possible to actually make things worse by applying (almost anything) poorly and setting up numerous moisture traps, which will accelerate the rust process. Options... Move somewhere dry (does not need to be hot, but often is). Dry out your 'Iron' / Heated / Airconditioned (Moisture out) Environments. or Coat your Product well (which is probably where most of us are). You Question is about Paint Adhesion... Land Rover (IMO) only just about covered the Chassis and Axles etc... yes there was talk about 'multi step Anti Corrosion Treatments' but the proof is in the Product, almost all Defenders when I look underneath have well established surface Rust, particularly on the Running Gear, with the Chassis, in some areas not far behind. From my experience I would say that what ever you do, expect to maintain it. Absolutely the key factors will be Preparation... Products Used and Application (so the whole Project  )
My experience is limited (four vehicles + 1 Caravan) but the best I think I have achieved is with Dinitrol. I spent around a week in total to do this on a Defender with 6K on the Clock it now has 50K and I'm about to 'Refresh' some areas, but it's lasted really well. The Process in Outline... 1. Power Washing / Degreasing / Salt removal and Drying of All Areas. 2. Removing all Loose Surface Rust. 3. Keying all surfaces, (Scotch bright or similar) this is tedious but... well Key! 4. Using Fe123 from Rustbuster (rubbish name but good product). 5. Use a quality 2 Pack Epoxy Paint on key areas (those poorly painted... so most of it!). 5. Apply Preparation Dinitrol Products. 6. Apply 3 Coats of Dinitrol Top Coat Product (Mist Coat + 2 Main Coats). My Approach... https://www.defender2.net/forum/topic10467...;start=165  Click image to enlarge I completed this in 2013, and I've been really (really) please how well this Product has lasted. If I really clean the underside, beyond 'normal' cleaning every few weeks of so, then the original unbroken finish looks to be there... effectively completely intact. A few Jacking Points on the Axles are the only (acceptably) casualties over the years... Big effort, but I've no regrets and would repeat this approach, or a very similar version of it, if I needed to again. Good Luck... SKIP https://www.defender2.net/forum/topic83242.html |
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22nd Mar 2022 9:43am |
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| Mossberg Member Since: 29 Feb 2020 Location: Lancs Posts: 553 
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So looking at this, the use of the IPA is to remove all traces of grease etc. I will make sure all grease is removed and then apply phosphoric acid to try and kill off any rest hiding in the pitting, but it dies look like the electrolysis is killing the rust but leaving the black residue. So after using the phosphoric, use the alcohol wipe over thus before painting? Just a quick question - could I use the thinners or brake cleaner to do the same job as the panel wipe/IPA on the bare steel as I already have that on the shelf - this is ONLY for wiping down the bare steel as I should be able to get some IPA by the time I have the first coat on. Regarding IPA - where is the best place to get it? If I know where to get it I may be able to pick some up today, otherwise I will have to order online so probably 2-3 days. Skip, I think your approach would be great if my chassis was not in the state its in. Unfortunately, due to the maturity of mine I am conscious of covering problem patches, though once I am happy with it I may go that route. I have currently covered it with Lanoguard so I can monitor it, as my thoughts are it may be a new chassis in the future so would go galv. I will do the internal chassis rails at some point, but I want to get the rusty bits sorted over the summer before I do that as I don't want to damage the newly applied coating within a month or two! Thanks for your responses folks, your knowledge will help me but also I am sure others will benefit from reading of your experiences. |
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22nd Mar 2022 10:27am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17432 
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When LR spoke of "multi step Anti Corrosion Treatments" what they neglected to mention was that the factory only took the first step, all subsequent steps have to be taken by the vehicle's future owners.
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22nd Mar 2022 10:50am |
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| X4SKP Member Since: 29 Nov 2013 Location: Berkshire Posts: 2295
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Hello Mossberg
Break Cleaner Is a fast-drying solvent cleaner and is good enough to wipe down most surfaces prior to painting* * accept getting it anywhere near a Powder Coated Part, which softens the coating making repainting very difficult if not impossible. Lanogaurd Is an excellent product i'd be happy to use this, I completed a TVR Chassis with this and it worked really well, Preparation as ever is key, there such a temptation to get to the Top Coat but resist! Your Defender It sounds like naturalising your existing (maybe extensive) Rust is the main first step... A good Converter is the best you can do hear, remove loose Rust first, but the hard surface rust that remains is essential for the converter to work (it actually needs this), turning a dark purple/black finish. Rust Converter FE123 gives a hard shell like finish when converted, key again this new surface (more gently) than else where and then apply your paint of choice... you could stop here. Dinitrol For me going the next step was the main 'safeguard', protecting the paint Preparation below. The Dinitrol Route gives a sort of cushioned but hard enough protective 'Top Coat' there is a sense that the Dinitrol is just compliant enough to deal with vibration, water spray, stone chips etc (they do a wheel arch specific version) and to my eye does not look to have let water through the overall layered approach. The dangerous / damaging rust on a Defender is mainly from the inside out, so eating through the Chassis until it is structurally compromised. Relatively Thin Chassis add on like Outriggers will be compromised normally at junctions around weld points where the Painted junction breaks down. A Galvanised Chassis swap would be a game changer and although can be left as-is there is a whole other world of how to paint a Galvanised Coating where White Vinegar wipe down and Acrylic Paints come into their own... Good luck... SKIP https://www.defender2.net/forum/topic83242.html Last edited by X4SKP on 22nd Mar 2022 11:55am. Edited 2 times in total |
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22nd Mar 2022 11:45am |
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| X4SKP Member Since: 29 Nov 2013 Location: Berkshire Posts: 2295
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What truth you speak oh wise one...  SKIP
https://www.defender2.net/forum/topic83242.html |
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22nd Mar 2022 11:48am |
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| Shroppy Member Since: 25 Feb 2016 Location: Shropshire Posts: 866
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Hi Mossberg,
You may need to scotchbrite the areas you have treated with phosphoric acid / electrolysis and be sure to rinse off all traces of any chemicals as they can react with the paint system. Then yes, IPA / Panel wipe immediately before painting to remove any final traces or fingerprints / chemicals etc. Brake cleaner would be ok, thinners no. Unless the thinners are the appropriate ones for the paint system you are going to use. Even then, I'd recommend IPA / panel wipe. You can buy both in 5L quantities relatively cheaply online or at your local paint shop. 1985 127 V8 Build Thread Series 2 109" Series 1 80" |
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22nd Mar 2022 11:57am |
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| Mossberg Member Since: 29 Feb 2020 Location: Lancs Posts: 553
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Click image to enlarge Click image to enlarge Click image to enlarge Click image to enlarge Click image to enlarge Click image to enlarge Click image to enlarge Some photos of the replacement axle casing during various stages of cleaning, ending with some phosphoric acid applied. (Oops - I seem to have them in the wrong order! Click image to enlarge |
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22nd Mar 2022 5:04pm |
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| Screbble Member Since: 26 Apr 2015 Location: Lancashire Posts: 2103 
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You’re doing a grand job
Looking forward to seeing the pics of you eating your dinner of it
Keep the pics coming. |
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23rd Mar 2022 6:53am |
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| 100inch Member Since: 15 May 2012 Location: Brunswick Posts: 411  
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The best way is still sandblasting, followed by good quality zinc primer within max2-4 hours of blasting...bit like welding. All in the preparation.m
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23rd Mar 2022 7:09am |
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| Mossberg Member Since: 29 Feb 2020 Location: Lancs Posts: 553
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I would agree about shotblasting as it will remove all the paint etc, but this is being done to a budget and everything in the main is being done by me. I did see a set of blasted axle cases on ebay but unfortunately after I had purchased this one.
I have tried to remove the paint with the wire brush in the grinder, but it is being stubborn to the extent that I am just going to scotchbrite it before painting. This refurb is for longevity rather than looks so I hope this will suffice. One thing that has impressed me with electrolysis is its ability to get to those places you just wouldn't reach with other methods whilst not attacking good steel. I certainly don't think wire brushing is adequate. Where the rust on this was crusty and thick (mainly on the welds), the wire brush removed the surface rust then polished the stuff underneath. A needle gun would probably have worked, but I ain't got one! Electrolysis is relatively cheap to set up and you can just keep using it over and over. The only consumables are soda crystals and sacrificial anodes. I am using an old style battery charger which is showing about 4 Amos on the 12v setting, but not sure how that equates to electricity use/cost. You still need to wire brush and scrape/poke after electrolysis but I feel it removes a great deal of rust. The part is often wet when doing this so you get a local mess rather than the airborne dust from wire brushing rust - this makes a big difference to me as even when wearing a dust mask I still end up with it up my nose, which means I am breathing it in. A pressure washer is very useful for cleaning after electrolysis, but obviously you need somewhere appropriate to use it. I have gone from a 40 ltr bucket to a 200 ltr barrel. I think this will become a permanent setup as I prefer this method where you have suitably sizes parts. A shot blaster would be nice though! |
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23rd Mar 2022 7:55am |
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| X4SKP Member Since: 29 Nov 2013 Location: Berkshire Posts: 2295
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Hello Mossberg
Great job, looks really well done so far, with the description you’ve given I wouldn’t worry too much about removing all the paint… there will be areas that ‘put up a fight’ take these as well adhered 
Good to see the effort at the preparation stage, you’ll get what you’re looking for with this approach. Continue to Show and Tell… SKIP
https://www.defender2.net/forum/topic83242.html |
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23rd Mar 2022 9:00am |
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| Mossberg Member Since: 29 Feb 2020 Location: Lancs Posts: 553
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Well, talk about two steps forward and one step back! After applying the phosphoric acid yesterday afternoon, it seemed to be doing a nice job of sorting the remaining residue After the electrolysis and brushing. I ended up going out after I had done it and was back later than expected, so I didn't want to start moving it without washing it down due to the acid, so decided to leave it out overnight as we were due no rain.
Anyhow, got up this morning and had a quick look before nipping out. I looked and it was covered in condensation - never thought of that! Never mind me thinks, I will wash it down when I get back. We'll an hour and a half later I got back and looked at it. What the f*** - the condensation had dried and left a scaly residue on the surface. Unfortunately I tried pressure washing, and whilst it removed some, wire brushing was required to loosen it. Joy! When wire brushing dust was coming off. A bit of a pressure wash again and as I was getting a milky look to the water as I scrubbed. Anyway I wire brushed and pressure washed and it came up clean. I was going to leave it a couple of days before painting, but flash rusting started to occur. I decided I would paint it today. I let the axle dry then scotchbright, brake cleaner and wipe. I then applied Bonda Rust Primer. One coat then the next, they both went on thick, with the odd run here and there, but I think I got it covered. I then let it cure under infrared (it was sunny this afternoon!). Some photos. Click image to enlarge Click image to enlarge Click image to enlarge Click image to enlarge Click image to enlarge |
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23rd Mar 2022 8:07pm |
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| Screbble Member Since: 26 Apr 2015 Location: Lancashire Posts: 2103
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Crumbs - sounds like you’ve had quite a challenge and some really bad luck - but the painted axle looks really good from what I can see.
You’ve probably done a far better job than most
Just a thought promoted by your pics - I was wondering if you might want to remove the bush cups on the shock absorber rear mounting brackets? Click image to enlarge |
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23rd Mar 2022 9:56pm |
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