How to tackle rusty underside?

[Yingyz]

Hi all,

I’m in possession of a fairly rusty LS600h from 2012 that unfortunately spent most of its life in Scotland so the underside has quite a bit of surface rust due to salt.

I’m planning on getting a bunch of Bilt Hamber anti-corrosion products and scraping as much of the rust off as possible.

Does the below sound about right?

 

1: Degrease with Surfex HD and rinse off and leave to dry.

2: Wire brush off as much rust as possible.

3: Apply hydrate 80 to reachable areas.

4: Coat with Dynax UB using brush and Dynax spray.

5: Repeat step 4 multiple times to build up 3-4 coatings.

Attached photos to show how the current state of the car. Does it look like surface rust or do I need to find a welder soon?

 

 

 

 

[Malc1]

Did the last MOT mention “ rust “. ? 
Malc 

[VFR]

To my eye I see nothing that needs welding in your pictures. 

Plenty of rust though so needs a lot of attention (as you know) sooner rather than later and what you propose in your plan will do no harm that’s for sure. 

[Yingyz]

1 hour ago, Malc1 said:

Did the last MOT mention “ rust “. ? 
Malc 

No mention of rust, asked tester if I have a rust issue and he said no it’s fine.

 

 Though I don’t think that’s very accurate looking at the photos my mechanic sent me.

[S.H.]

Youtube Repair Geek https://www.youtube.com/watch?v=QqbnNNZRF-c&list=PLdZ4W-5tDUwHDA_F2VZWOEpJcZ81BEu4B&index=5

all about rust coating, only facts.   I use this myself on surface rusted cars. Go through his videos before anything else, that could save you frustrating outcomes.

Good luck.

Edited Friday at 05:48 AM by S.H.

[ambermarine]

The subframe is the worst as are those pipes which need checking out for replacement where plastic shrouds meet or cover the sills and floor remove them as there is likely rust under them.The wire brush will take off scale but you must use a rust inhibitor before aplying any protective coats.

[steve2006]

Looks mainly cosmetic rust and pretty sure structural rust would have been flagged on the MOT. I would be more concerned regarding the pipe works suggesting replacement of those shown and a thorough inspection of all the others particularly the rear brake pipes which are known for corrosion on earlier LS models. 

Scottish road salt eh!

[Yingyz]

1 hour ago, steve2006 said:

Looks mainly cosmetic rust and pretty sure structural rust would have been flagged on the MOT. I would be more concerned regarding the pipe works suggesting replacement of those shown and a thorough inspection of all the others particularly the rear brake pipes which are known for corrosion on earlier LS models. 

Scottish road salt eh!

That really rusted pipe is actually the fuel filler pipe, it’s very rusty and I’m thinking eventually I’ll need to get it replaced.

 

I’ve had the rear brake pipes rust treated and taken care of by my mechanic because they started to get pretty rusty. 

[S.H.]

If you want to save this car, then DO NOT WASH IT and use Fluid Film with a pressure gun and let the air pressure take out the loose dirt and surface rust. First round will disappear

after few days then put another round and more rust will go, minimum 2 carefully non saving and lot of elbow greasy time and effort and you will be rewarded. 

this is what I use on my winter salt bucket (Getz) except do not use the Bitumen like in the picture (that is for new paint)

[ColinBarber]

19 hours ago, Yingyz said:

4: Coat with Dynax UB using brush and Dynax spray.

All sounds good but just remember that Dynax-UB is brown so you might get MOT comments that they cannot check for corrosion. Dynax-UC on brake lines, suspension springs etc. would avoid advisories. 

[ambermarine]

7 hours ago, steve2006 said:

Looks mainly cosmetic rust and pretty sure structural rust would have been flagged on the MOT. I would be more concerned regarding the pipe works suggesting replacement of those shown and a thorough inspection of all the others particularly the rear brake pipes which are known for corrosion on earlier LS models. 

Scottish road salt eh!

When I resided in Argyll in the noughties there was a shortage of salt Nationwide in one particularly bad winter and the argyll & Bute used a chemical formula on the roads and it wrecked my Mark 1 so much so It rotted out the rear suspension and the cills.

[steve2006]

1 hour ago, ambermarine said:

When I resided in Argyll in the noughties there was a shortage of salt Nationwide in one particularly bad winter and the argyll & Bute used a chemical formula on the roads and it wrecked my Mark 1 so much so It rotted out the rear suspension and the cills.

Rumour has it the stuff used came from a local distillery and it was tested on old oak barrels first which were unaffected before use on the roads 😀

[S.H.]

Repair Geek

Coated vs Uncoated After 7 Years: The ULTIMATE PROOF Lanolin Undercoating Works!

[Yingyz]

Pete Hamber recommends Dynax UB, and Hydrate 80 if I can get rid of the surface rust.

 

 

[S.H.]

On 11/10/2024 at 12:21 AM, Yingyz said:

Pete Hamber recommends Dynax UB, and Hydrate 80 if I can get rid of the surface rust.

 

 

Dynax UB is (Forms a touch-dry, brown, wax-like film that does not peel or flake off like traditional bitumen underseals)    and Hydrate 80 is (Converts rust into a stable, protective metal complex)   For me this formula is for light surface rust, Hydrate 80 is just a rust converter..  (they all work similar).    In all instances I use Fluid Film FROM A PRESSURE CAN, reason the pressurized air blow off dirt/rust, after each round more rust will flake off. Some use Fluid Film in sills and cavities but a thicker fluid like the wool wax (or similar) on open air places.  Look at RepairGeek then you see exactly what I am talking about. Like on my 2008 Getz winter salt bucket you can see on some panel connections it seeps through after few weeks after I wash the car where thicker Lanolin types do not. I have used few types of rust converters but I only use it on the body and prime or just paint over it. Waxing or + nano coat does breath in the end and I need to re rust convert that spot (if not painted).  I am 63 and 90% of my cars have rusted down to Fred Flintston style ...... but I could always drive them. When I got the Getz about 8 years ago I told my self now I will learn this finally and buy the right tools for it and every year before inspection I Fluid Film the underbody and say to my self Ill give him 3 years.... He will not go to the scrapyard cos of rust no when the Catalytic converter and the turbo rust out I will need to make a decision... My guess is I would fix it... time will tell... kind regards

[Yingyz]

6 hours ago, S.H. said:

Dynax UB is (Forms a touch-dry, brown, wax-like film that does not peel or flake off like traditional bitumen underseals)    and Hydrate 80 is (Converts rust into a stable, protective metal complex)   For me this formula is for light surface rust, Hydrate 80 is just a rust converter..  (they all work similar).    In all instances I use Fluid Film FROM A PRESSURE CAN, reason the pressurized air blow off dirt/rust, after each round more rust will flake off. Some use Fluid Film in sills and cavities but a thicker fluid like the wool wax (or similar) on open air places.  Look at RepairGeek then you see exactly what I am talking about. Like on my 2008 Getz winter salt bucket you can see on some panel connections it seeps through after few weeks after I wash the car where thicker Lanolin types do not. I have used few types of rust converters but I only use it on the body and prime or just paint over it. Waxing or + nano coat does breath in the end and I need to re rust convert that spot (if not painted).  I am 63 and 90% of my cars have rusted down to Fred Flintston style ...... but I could always drive them. When I got the Getz about 8 years ago I told my self now I will learn this finally and buy the right tools for it and every year before inspection I Fluid Film the underbody and say to my self Ill give him 3 years.... He will not go to the scrapyard cos of rust no when the Catalytic converter and the turbo rust out I will need to make a decision... My guess is I would fix it... time will tell... kind regards

Is fluid film a US lanolin based wax coating? 

[HensTeeth]

1 hour ago, Yingyz said:

Is fluid film a US lanolin based wax coating? 

Oil based. The advantage it has is that it never sets and will continue to creep into rust for ages after its applied. The downside is that it's messier than waxes which set to a greater or lesser extent and will wash off faster so it'll need doing annually, at least for the first few years, but it's quite good for rusty areas that are hard to get to.

Sadly there's no one perfect solution once rust is present - it's all trade-offs.  Speaking from personal experience of using their corrosion removal, neutralisation, arresting etc. products over more than 10 years is that the Bill Hamber range is excellent and does what it says it'll do, so long as you follow the instructions.

Whatever you use, there's nothing that's a one and done. Everything is messier than a painted surface, but what good is not messy when stones and salt degrade the paint and it comes off.

If you're doing it yourself and want the rust back to shiny metal, the poly strip wheels on angle grinders and drills are fabulous at getting rid of rust but not removing excess metal. The problem is you can't get them into most of the places you really need to get them into like all the pipework and intricacies of the subframes and behind. That's why BH suggest you wire brush and remove what scale you can and then just apply Dynax wax and keep a regular eye on it. https://bilthamber.com/faq/can-i-use-rust-removers-and-paint-coatings-to-protect-a-rusted-vehicle-underside/ 

[S.H.]

9 hours ago, Yingyz said:

Is fluid film a US lanolin based wax coating? 

Yes, and sometimes referred as wool wax.

https://www.fluid-film.com/

FLUID FILM® is Eureka’s own unique lanolin-based brand of corrosion preventive and lubricant, used Worldwide in a multitude of industries and applications.

I did test the thicker type but that did not work for me it was to thick (did not bond well) or is for warmer climate, close to a bread butter in viscosity.   And ohh yes it is messy but it is the only fluid that I trust to penetrate through almost anything ... it is an oil base... in that way that it mixes with Bitumen (some underbody coatings include a small % of Lanolin to make it less brittle when fully hardened), see SDS papers.

 If a thinner version is wanted, start by mixing a small amount of vegetable oil to the product until the desired consistency is reached. (I have not tested this, I just warm up my can more if needed).  P.S. your fuel tank I would cover it with Fluid Film even if you want to use other methods for the rest of your car.

 Your car is so badly surface rusted that I would always start with Fluid Film, I use HQ borescope in closed chambers if I really want to see what I am doing,  but that is me.