And so it begins.. tackling r230 wheel arch rust.

[Conor]

Mirror???

Yes.. exactly that. I wasn't sure how well it would work, but very well, thank you. Combined with a torch was great, but lack of a third hand means no photo. Take my word for it... it was an epic performance!

 

[Conor]

Right...

So today I had another go at this. I bought an angle grinder and heat gun (just because!) + discs + face guard during the week and wanted to try it all out. The wire wheel works quite well, but a couple of stray wires scratch up some unexpected areas, no biggie, but I will trim them next time.

I didn't really get much use of the grinder as I needed to continue preparation + investigation. I partially removed the side skirts as the rust had gone that way too. Broke one of the tabs on both N/S and O/S, but hopefully won't be a deal breaker later on.

I also removed all the grime on the arch inner lips using a cloth and some very soapy water. I discovered there is some kind of rubber coating on the inside lip that seems have had no effect. I suppose it was intended to resist stone chips... but the collected dirt and grime did that.. and the rust also crept in under it.

The rubber coating was quite deceptive actually, because when I had cleaned the surface, running my finders along felt smooth. But it wasn't until closer inspection with mirror + torch (and general gut feeling) that I noticed the bubbling and could see where the rust had crept it.

You can also see in one of the photos, there is a pick hanging from the rust.. it is the same on the inside too.

As shown in the drawing below, the lip protrudes a bit, meaning the angle grinder is definitely not getting in, but maybe the Dremel. I could definitely hand sand with some heavy grit paper. Also, doesn't appear to be as bad as the surface "parallel" to the road.

Now...the conundrum:

I am seriously considering grinding back a bit of the lip to help with access and inspection, which will help me confirm when the area is 100% prepped. Also, from inspecting the arch on my S212, it looks like a very similar design but with no meaningful lip. The lip is probably only a 5 or 10mm. There was still CRUD on the S212...but no rust!

Anyway... I am trying to see a downside of grinding back this lip. Also, a friend of a friend who lives in the USA and operates around some serious cars (He fabs his own carbon panels, and says he has fixes on a Veyron and also rust on an F50), has said I should just grind back the lip a bit so I can prep/treat it then "Bondo" the whole thing around to fill it to prevent relapse.

Once the area is fully cleaned and rust removed I am finding it difficult to reason against it, since I have been pondering how to fill that void to prevent dirt ingress in the future. The Bondo could also come around the edge onto the bottom surface, to protect the edge also..

Thoughts....?



My new kit... (more pics to follow).

 

[Conor]

You can see here where I scratched the treatment to check the texture.

 

[Conor]

Busy week everybody.....

And for my next trick: A post that is certainly not for the squeamish / faint of heart when it comes to chopping lumps off your prized automobile....

So.. I did plenty of more inspection and just couldn't figure out how I was going to confidently get at / remove "all" the rust without removing the inner lip of the arch. It just had to go :/

I cut off most of the vertical piece of that inner lip, as shown in various photos below. I will be first to admit the job I ended up doing certainly won't win any prizes. And some might argue it should never be done, for risk of splitting the arches.

With that said, after getting over the fact that I butchered my car, I took some solace in finding rust inside where the inner arch/wheel well and quarter panel meet. This would have been impossible to get to, but now it's gone.

-- Slide aside--
Once the fix is done I am going to get some U channel (Thanks @television for the tip!) and run it along where I chopped off. I am not sure if I would fill the U channel with seam sealer or wax oyl..and if I would covert the U channel with Seam sealer after. I need to get advice on how to approach that and not do a shotgun approach while missing the target....
-----------------

Now that I have put away grinder, before I could do any more damage preparation. I moved onto treatment. Cleaned up with BH Surfex and ensured it was dry with heat gun.

Next up was Bilt Hamber Deox Gel (Rust Remover) all over the exposed metal and covered with Cling Film and covered with carrier bag to protect from the rain.

Tomorrow I will be washing all the Deox Gel off with Surfex was and Methylated spirits and inspecting. I may apply more Deox gel or get the Dremel out with grinder to clean up some missed spots before more gel. This is a very tricky job and there are many intricate places to get to, primarily down around the rear bumper join area and the side skirt join area. I think I will remove the skirts tomorrow as they are kind of in the way and I want to ensure I have no small bits of rust hiding.

Progressing from the rust remover to following stage is time sensitive as I don't want the metal to be exposed for any length, as even the humidity in the air can start the rust process again.. With that in mind, I have my BH Hydrate 80 rust converter to apply to the metal to pick up any missed rust and then I will apply some 2K epoxy primer I picked up. Beware that anything 2K is extremely hazardous to your body. I need to get some proper respiratory PPE before applying that.

I think that's it for the moment.

This thread has some high level photos and I will share more in depth ones after. I have tried to take some decent photos/angles of the arch lip that I chopped off so that you can see how the pieces have rusted etc.

Below you have the arch: Before, the removed piece and after removal.

 

[Conor]

Another 10 photos...

 

[Conor]

 

[Conor]

 

[Wighty]

Madrid de dios x10000 !
Excellent work buddy , that took some cojones
Sell it to someone on MBClub UK when you are finished

 

[Wighty]

Just chuckling to myself , a new member was having hassle with getting his 2017 cars service record , he needs to read this

 

[Conor]

@Wighty what does all that mean? Lol.

I think it should all be fine. One potential pitfall is the visibility of the U channels given the shorter lip....

 

[Conor]

What I think is hilarious is the silence lately.

Everybody at home reading and wincing.. Better off saying nothing lol

 

[LostKiwi]

Rather than use U channel get it all done then give it a coat of stone chip paint.
The guy that did ours did that and it's immaculate 3 years on.

 

[Wighty]

What I think is hilarious is the silence lately.

Everybody at home reading and wincing.. Better off saying nothing lol

Can’t speak from any experience of rust , but your approach seems logical and you’ve done your research . Everyone is out drinking the pubs have opened

 

[Conor]

Rather than use U channel get it all done then give it a coat of stone chip paint.
The guy that did ours did that and it's immaculate 3 years on.

Fair enough. I was thinking seam sealer might work.. Is there much different with stone chip paint?

I still like the concept of the U channel though as the metal is quite exposed. Some might say more than it was before but its pretty much the same because the sealer doesn't actually cover the seam.

Rubberstock.com has some nice tidy bits there.

 

[LostKiwi]

The problem with U channel is it allows water under the surface. You can seal with a silicone sealant but you can't tell if there's a gap water can get past.
A good stone chip paint bonds to the metal but is resistant to knocks and stones. Some can also be overpainted to match body colour.

 

[Conor]

The problem with U channel is it allows water under the surface. You can seal with a silicone sealant but you can't tell if there's a gap water can get past.
A good stone chip paint bonds to the metal but is resistant to knocks and stones. Some can also be overpainted to match body colour.

Interesting. I need to investigate the approach but I was thinking the channel could be filled with sealer or stuff/injected after.

Or else do the same with wax oyl and keep on top of it.

Consdiering all options.

 

[alexanderfoti]

When I do rust repair on inner arches, the lips that stick into the arch etc, We go back to metal, then etch prime, then normal prime, then stone chip, then paint the cars colour on top.

Not had rust come back from that yet.

 

[McDonald]

I asked the body shop about putting something behind the lip to stop muck building up. The answer was no, damp will get trapped and rust will be promoted. I was resistant to stone-chip paint as I think it looks ugly. The man has persuaded me that there is a smooth variety which will look very like the original but will be much more robust. I'll be following that guidance and hoping it doesn't look cheap & nasty.

 

[LostKiwi]

I asked the body shop about putting something behind the lip to stop muck building up. The answer was no, damp will get trapped and rust will be promoted. I was resistant to stone-chip paint as I think it looks ugly. The man has persuaded me that there is a smooth variety which will look very like the original but will be much more robust. I'll be following that guidance and hoping it doesn't look cheap & nasty.

If you're only applying it under the wheel arch no one will see it (unless you run them over).

 

[wizzman]

Ha ! Having similar problems up ere in the north !Had to chop a neat section out to get to an 8 inch section of rot on the inner arch. First picture is the patch I fabricated then welded in then re attached the section of outer arch neatly. The best tool for the rust is a 3M strip and clean disc used with air drill or electric drill. The discs are around 100 mm in diameter and you can get right round the back of the lip with them. Best tool for complete rust removal is called an MBX blaster but they are an air tool and £300....happy days