Front Arch Corrosion / Painting

Matt182! · Aug 10, 2023

Hi all, been gradually going through my 182 (when the weather allows), cleaning it up and removing the worst corrosion where I can see it. In the front wheel arches there is corrosion behind the front liner and also a small amount along the back edge.

However I am a bit stumped about what to do in terms of finishing / painting. So far I have been using Electrox primer and then coating with Inferno spray paint. However, the wheel arch is a much lighter colour so I am thinking that it would look quite patchy with inferno bits here and there so I only see three options:

1. Inferno Spray the whole arch (not massively keen)
2. Inferno Spray the bits that need doing (might look a bit patchy, however not a massively on show anyway...)
3. Underseal the whole thing (also not massively keen)

Just wondering if anyone has any other suggestions or examples of what they have done.

Many thanks.

Robbie Corbett · Aug 10, 2023

How much do you see the wheel arch when the wheel is on the car?

I would epoxy the lot, re apply seam sealer, stone chip (grey) and then paint it orange. You will need to take the front wings off to sort the front bumper mounts too.

Mr Underhill · Aug 10, 2023

I'd go with option 1 and finish the job Renault should have done in the first place. It's barely noticeable with the wheels on anyway.

Mr Underhill · Aug 10, 2023

And this is mine 18 months later. Took this shot last Saturday after a quick wash down with Atom Mac and dried it with a cloth. I've since touched everything up again so it now looks like the above shot.

1. Degreaser
2. Agitate corrosion
3. Hydrate - 80
4. Electrox primer
5. Aerosol of paint for local store brushed on

The car is used on the road over the summer and stored outside over winter. I just keep on top of it and top up ACF-50 on other parts.

Matt182! · Aug 10, 2023

Touring_Rob said:
How much do you see the wheel arch when the wheel is on the car?

I would epoxy the lot, re apply seam sealer, stone chip (grey) and then paint it orange. You will need to take the front wings off to sort the front bumper mounts too.

Mr Underhill said:
And this is mine 18 months later. Took this shot last Saturday after a quick wash down with Atom Mac and dried it with a cloth. I've since touched everything up again so it now looks like the above shot.

1. Degreaser
2. Agitate corrosion
3. Hydrate - 80
4. Electrox primer
5. Aerosol of paint for local store brushed on

The car is used on the road over the summer and stored outside over winter. I just keep on top of it and top up ACF-50 on other parts.

Thanks both of you, like you say it won't be that visible anyway with the wheels back on, I'm probably just overthinking it as it's my first time doing anything like this. I do think painting the whole thing is probably the best option, I was just worried about how "loud" it would look.

Love your work on the rb, been following your build thread for a while and it's top notch, I want to be that good!

Got the whole front of the car in pieces at the moment, already done the front bumper brackets (they were pretty bad actually), and started the sills yesterday, again don't judge the work 😂.

Mr Underhill · Aug 10, 2023

Cracking job. Just take your time! Get some Dynax S50 in the seams, behind the rear door cards and inner sills. There's a little sticker on the sill. Peel it back and shove the lance that comes with the S50 in there. It's easy to use, but ugly stuff so just use it in the places you can't see.

They also do a UB version which I use under the bonnet, door hinges, petrol flap etc....

Keeping on top is the name of the game and you've made a good start.

Matt182! · Aug 10, 2023

Mr Underhill said:
Cracking job. Just take your time! Get some Dynax S50 in the seams, behind the rear door cards and inner sills. There's a little sticker on the sill. Peel it back and shove the lance that comes with the S50 in there. It's easy to use, but ugly stuff so just use it in the places you can't see.

They also do a UB version which I use under the bonnet, door hinges, petrol flap etc....

Keeping on top is the name of the game and you've made a good start.

I'm all stocked up on the Bilt Hamber products ha!

Definitely doing the inner sills soon, the corrosion doesn't seem too bad thankfully...

Thanks!

Robbie Corbett · Aug 10, 2023

Do Bilt Hamber do an epoxy mastic undercoat type stuff? I can't praise Epoxy enough, no corrosion has come back on any parts done in epoxy on mine and its been a fair while since I did them.

Mr Underhill · Aug 10, 2023

Touring_Rob said:
Do Bilt Hamber do an epoxy mastic undercoat type stuff? I can't praise Epoxy enough, no corrosion has come back on any parts done in epoxy on mine and its been a fair while since I did them.

Yes they do. I used it on my rear beam, hubs, subframe etc. It dries really hard. Ideal for steel or alloy.

Wurth do a stone guard underseal which can be over painted. Probably better than the expoxy as it’ll be more flexible and won’t crack.

Robbie Corbett · Aug 10, 2023

Mr Underhill said:
Yes they do. I used it on my rear beam, hubs, subframe etc. It dries really hard. Ideal for steel or alloy.

Wurth do a stone guard underseal which can be over painted. Probably better than the expoxy as it’ll be more flexible and won’t crack.

Epoxy mastic with stone chip over the top. It bonds to the substrate better than nearly everything else. Mastic 121 isn't rock hard when cured so stays flexible enough.

I used upol over paintable stuff on my escort but wish I had done the car in epoxy first then stone chip.

Matt182! · Aug 11, 2023

I'm a bit clueless when it comes to the epoxy products.

Would you use an Epoxy product on top of a zinc primer, then you can paint over the epoxy with a colour? (Sort of an extra layer of protection?)

Mr Underhill said:
I'd go with option 1 and finish the job Renault should have done in the first place. It's barely noticeable with the wheels on anyway.

View attachment 1655705

Is the subframe in this picture the pure Epoxy finish or has this been overcoated with something else after the epoxy? (I assume the hubs have paint on them?)

Many thanks again.

Robbie Corbett · Aug 11, 2023

Matt182! said:
I'm a bit clueless when it comes to the epoxy products.

Would you use an Epoxy product on top of a zinc primer, then you can paint over the epoxy with a colour? (Sort of an extra layer of protection?)

Is the subframe in this picture the pure Epoxy finish or has this been overcoated with something else after the epoxy? (I assume the hubs have paint on them?)

Many thanks again.

I'm not 100% on the zinc primer. *Epoxy - I have only ever used it on very clean and bare metal. The idea is that it bonds so well no oxygen can get to the metal, no oxygen no corrosion which is why some people use it direct over corrosion.

I have had car parts powder coated in the past and it looks fantastic but its often very hard so chips off from edges easily then you get focused corrosion in the chipped areas. The epoxy mastic 121 I have used from rust.co.uk I think cures well and seems to be soft enough to not crack. All the parts I did with etch primer then dinitrol underbody black show signs of corrosion 3 years later while all the epoxy coated sections are still good.

Next time I do a full car again I will do bare metal - epoxy - either upol or Wurth over paintable stonechip/undercoat paint and then soft wax or lano-guard every winter. The Raptor stuff is supposedly very good as well as the products from buzz welding although I've never used either to date.

The epoxy bonds to the metal well enough that you can use filler or seam sealer on top of the epoxy.

Robbie Corbett · Aug 11, 2023

PS I've also not used the Bilt Hamber products but all I read are really good reviews so will dive in at some point.

As I'm sure you already know, the idea behind zinc is that it becomes a sacrificial layer which corrodes instead of the base metal. The trouble with spray on zinc is that you are reliant on the bond strength between the zinc spray and the base metal which is unlike the OEM plating process where the zinc bonds with the steel at a molecular level. It gets used as a weld through primer as is more effective there I suspect.

Although people use it regularly for anti corrosion I personally don't and have had better success with an etch primer followed by a regular coating, by better I mean I can't scratch it off after!

Mr Underhill · Aug 11, 2023

Matt182! said:
I'm a bit clueless when it comes to the epoxy products.

Would you use an Epoxy product on top of a zinc primer, then you can paint over the epoxy with a colour? (Sort of an extra layer of protection?)

Is the subframe in this picture the pure Epoxy finish or has this been overcoated with something else after the epoxy? (I assume the hubs have paint on them?)

Many thanks again.

Yes. Epoxy on pretty much all those parts.

The process i used on those parts were:

1. Degrease
2. Descale
3. Deox-c (on really rusty stuff)
3. Hydrate 80
4. Electrox
5. Expoxy
6. Paint (where applicable)

The only one that I didn't do was that wishbone stabiliser and you can see how it's started to rust around the bolt in my 18-month-old picture. Other than that, it's been amazing stuff. I don't drive mine in the winter though, so not overly exposed to salt etc....

Robbie Corbett · Aug 11, 2023

Sorry just edited my first post for clarity.

Robbie Corbett · Aug 11, 2023

Is hydrate-80 the stuff that turns black after a while? I think its latex based or am I thinking of something different?

Mr Underhill · Aug 11, 2023

And the ARB needs resorting as that was properly crusty and I should have had that shot blasted.

Mr Underhill · Aug 11, 2023

Touring_Rob said:
Is hydrate-80 the stuff that turns black after a while? I think its latex based or am I thinking of something different?

Yes. It's not perfect by any stretch though. I've seen corrosion coming through in 12 months of using it. When you can get parts off a vehicle and really get at them with chemical preparation, the results are better.

I'm always checking mine and retreating anyway, so my cars always stand the test of time.

Robbie Corbett · Aug 11, 2023

I'd like to do a few test pieces to see what lasts longer comparing different products and prep. Like hydrate 80 before epoxy compared to just epoxy. Lots of conflicting internet advice out there so ultimately you can only recommend stuff which has worked for you.

My ARB went to s**t too, I only used dinitrol on that as I was worried about it flexing too much for the epoxy.

Robbie Corbett · Aug 11, 2023

I saw a mates old LR recently and he's been using lano guard for the past couple of years. All the new parts he's fitted in that time still looks new, bolt heads etc. So I'm absolutely going to give it a go.

Mr Underhill · Aug 11, 2023

Cold weather plays a part as well.

Matt182! · Aug 11, 2023

Brilliant, thank you both so much for the insights it seems clearer now. It's a bit of a minefield all the different products and processes but I'm slowly getting there ha!

Touring_Rob said:
I'd like to do a few test pieces to see what lasts longer comparing different products and prep. Like hydrate 80 before epoxy compared to just epoxy. Lots of conflicting internet advice out there so ultimately you can only recommend stuff which has worked for you.

My ARB went to s**t too, I only used dinitrol on that as I was worried about it flexing too much for the epoxy.

Yeah I think some test pieces would be very interesting, like you say there's so much conflicting information that you just have to choose a process and go with it!

Just trying to do a decent job now to give the car the best chance, I don't think this car will see the salty roads again anyway...

Again many thanks to you both for the information, very helpful

Mr Underhill · Aug 11, 2023

Touring_Rob said:
I'd like to do a few test pieces to see what lasts longer comparing different products and prep. Like hydrate 80 before epoxy compared to just epoxy. Lots of conflicting internet advice out there so ultimately you can only recommend stuff which has worked for you.

My ARB went to s**t too, I only used dinitrol on that as I was worried about it flexing too much for the epoxy.

I did my rear beam with epoxy directly on the steel and it's started to lift again. I've got another rear beam in the garage which I've been working on and in a few months will unleash on the group haha (sad b*****d). It's going to be a thing of beauty.

Mr Underhill · Aug 11, 2023

Touring_Rob said:
I'd like to do a few test pieces to see what lasts longer comparing different products and prep. Like hydrate 80 before epoxy compared to just epoxy. Lots of conflicting internet advice out there so ultimately you can only recommend stuff which has worked for you.

My ARB went to s**t too, I only used dinitrol on that as I was worried about it flexing too much for the epoxy.

Yeah, it's the sheer hardness of the Epoxy that worries me on certain parts that can flex. If you took a piece of clean steel, coated it in Epoxy and stood it upright in the water, it wouldn't rust. That I'm sure. But it doesn't self-heal. That's why it's cracked on my rear beam. It also doesn't like sunlight, so goes white.

Mr Underhill · Aug 11, 2023

Matt182! said:
Brilliant, thank you both so much for the insights it seems clearer now. It's a bit of a minefield all the different products and processes but I'm slowly getting there ha!

Yeah I think some test pieces would be very interesting, like you say there's so much conflicting information that you just have to choose a process and go with it!

Just trying to do a decent job now to give the car the best chance, I don't think this car will see the salty roads again anyway...

Again many thanks to you both for the information, very helpful

No worries. Invest in some of their Atom Mac. If you look at my RB thread, I sprayed my brand new rear discs and dampers with it before storing it over winter. 6 months later there wasn't a single bit of rust on those discs. I think it's a bit like Lanoguard. You can literally spray it on anything. Just water it down and put it in a sprayer.

I've seen some detailers use it when they Karcher a vehicle off prior to detailing. Stops oxide coming through on the discs.

Robbie Corbett · Aug 11, 2023

Matt182! said:
Brilliant, thank you both so much for the insights it seems clearer now. It's a bit of a minefield all the different products and processes but I'm slowly getting there ha!

Yeah I think some test pieces would be very interesting, like you say there's so much conflicting information that you just have to choose a process and go with it!

Just trying to do a decent job now to give the car the best chance, I don't think this car will see the salty roads again anyway...

Again many thanks to you both for the information, very helpful

You're welcome mate, keep posting pics of the car!! It's looking great already 👍

Bmac · Feb 3, 2024

@Mr Underhill after you have painted the arches, do you put a laquer over it to protect it further and have you just used rattle cans for the paint? It looks like a great finish.

Mr Underhill · Feb 3, 2024

Bmac said:
@Mr Underhill after you have painted the arches, do you put a laquer over it to protect it further and have you just used rattle cans for the paint? It looks like a great finish.

Just paint but I guess you could if you wanted.

MrBlonde · Aug 25, 2024

With the rear inner doorcard area,go straight in there with the Dynax S50 or treat with Hydrate 80 first?

Robbie Corbett · Aug 25, 2024

The S50 is an anti corrosion wax, intended to prevent or stop corrosion not treat. Hydrate 80 is a corrosion converter, it converts the top layer of rust into a black oxide layer, they probably use latex as a carrier. Hydrate 80 does seem to adhere to the base metals better than other similar products. However if there is no Iron(III) present it won't do any 'converting'.

Personally, if you have no corrosion I would just use a cavity wax like S50, however if there is corrosion I would knock it back then use Hydrate 80 before the S50. Where I think Hydrate 80 works really well is where you have used a grinder to remove corrosion, but can't get into any pitting where there is remaining grot.

On clean metal, where something is either new or has been blasted epoxy wins over Hydrate 80.

Robbie Corbett · Aug 25, 2024

Mr Underhill said:
I did my rear beam with epoxy directly on the steel and it's started to lift again. I've got another rear beam in the garage which I've been working on and in a few months will unleash on the group haha (sad b*****d). It's going to be a thing of beauty.

Coming back to this, I did a little testing at work a while back for some gear that was being subsea tested. Epoxy coated areas won hands down but ONLY if the surface was blasted and then degreased, any areas that weren't degreased properly or didn't have a sufficient key the epoxy lifted. Its got to bond to the surface fully.

Failure seems to be where you get a chip, without the chip even with poor prep the epoxy seals well enough, but a new chip means water can creep under the epoxy layer (because it hasn't bonded properly) so you get corrosion between the epoxy and the base material so more epoxy lifts and flakes off. I think this is where rust converting stuff works fairly well, because it converts rust so kind of creeps into the corrosion later so adheres really well, while epoxy would just sit on top.

MrBlonde · Aug 25, 2024

Great info thanks @Touring_Rob

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