# Rear wheel arch rust repair



## Lugy (Nov 4, 2009)

I'm looking to have a go at doing a rust repair on the rear arches of my Saab, I bodged them using filler and a spray can kit from Carpaints4U, they finished better than they were however, I tend to lose patience and they definitely weren't my best work, the rust coming back through would confirm this!
Now I'm looking to have a second attempt with more success.
In our workshop we've got a proper compressor, now with water trap/filter/reg and I have a cheapy spray gun so I'd like to do it properly and I'm looking for guidance.
Not looking for a concourse finish, just something that looks tidy enough.
First stage would be treating the rust, would something like Bilt Hamber products work here?
Next my prep stages, filler/primer and then basecoat, I'll get a colour match from a local paint supplier and I'm going to have a go at blending with the spray gun, I guess this will be a similar idea as using rattle cans, I think this shouldn't be too much of a problem.
Finally the top coat, I've read that I might come into problems here, with clear lacquer being 'runnier' and needing a smaller nozzle on the gun. This is a bit over my station but I'd like to give it a bash and learn a bit! Any bits of info would be gratefully received!


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## mr paint (Jul 11, 2009)

Hi mate my recommendation would be ..

Buy 5 ltr of thinners and wash the full panel that you have painted ,
if not painting over this will cause you problems ...reactions etc .


Treat rust with what ever product you wish there all about the ssame tbh read the instructions and follow them .

After treatment you should seal the bare metal with an 2k epoxy primer 2 coats 

do filler work ontop of epoxy primer finishing all repairs on 320g paper DRY

Apply 2-3 coats of a 2k primer leave over night 

Sand with 400 on da sander dry or 600 wet by hand 

prep blend panels 

apply paint and blend adjacent panels 

Clear coat full panels DONT try to blend clear coat 


To make clear coating a bit easier use a MS clear coat and sit it on the radiator before you mix it ...also get the panels warm if you can 


tommy


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## Lugy (Nov 4, 2009)

Cheers, sounds like a decent method, I'll bear in mind about clear coating the whole panel, I'm sure that'd trip me up! No doubt I'll have more questions when I actually get started!


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## slim_boy_fat (Jun 23, 2006)

Sadly, unless you cut out the rust and replace with fresh metal, the chances are it'll keep coming back. 

Good luck and post up the results. :thumb:


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## Lugy (Nov 4, 2009)

If it was a newer or nicer car that I was a bit more attached to then I'd probably go down that road, as long as it looks a bit better for now, that'll do!


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## Lugy (Nov 4, 2009)

Operation 'Haveagoatpainting' is well underway. Unusually I spent a whole day doing the prep on Saturday (with my attention span that's quite incredible!) and the colour is going on today. Unfortunately the first attempt this morning saw the air supply go funky and made the paint go on 'blobby'. Decided to cut my losses and use a fair bit of my thinners taking it off again and started from scratch.

So far I've done quite a few coats of base, was some confusion between ratio's and what actually goes in the mixing pot, the paint I'm using is MaxMeyer MaxiCar HS mixed 1:1 with MaxMeyer Thinner 4130. Seems to be going on quite well so far.
Just put on my first coat of clear, using U-Pol scratch resistant clear, a pro would probably laugh at my work but it feels quite rewarding to see the shine coming through. I plan on putting on quite a lot of clear so there's lots on for when I inevitably need to wet sand it back after making a **** of it.


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## Lugy (Nov 4, 2009)

Finished applying paint now, inevitably something has gone a bit Pete Tong, in my enthusiasm to get a fair bit of clear on the panel I've got a few runs. Hopefully they'll be easily sorted with some wet sanding and a bit polishing. Something's also blistered so I'll see how that comes out after I do the finishing. I'm happy enough for my first attempt, just need to work on a few things (and not pile on the clear as much!).

Some pics....



See how I said a few runs, check the wheel arch....


The further away you get, the better it looks, by the time you're in the next county it looks amazing!


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## enc (Jan 25, 2006)

looks to be a fair bit of orange peel going on there fella ! that would suggest to me there's plenty of paint on there and fair scope for wet sanding back.... 

i think you might have been better with some pro mixed aerosols rather than using the sprau gun. but 10 out of 10 for having a go dude :thumb:


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## Sicskate (Oct 3, 2012)

I've never seen runs like that before?!?

But as above, well done for having a go


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## Aaran (Sep 18, 2007)

keep an eye out for solvent pop dropping that much clear on in one go.


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## Lugy (Nov 4, 2009)

enc said:


> looks to be a fair bit of orange peel going on there fella ! that would suggest to me there's plenty of paint on there and fair scope for wet sanding back....
> 
> i think you might have been better with some pro mixed aerosols rather than using the sprau gun. but 10 out of 10 for having a go dude :thumb:


Erm, yeah, I might have overdone the clear....

I've done the aerosol method before but I'd like to get in about the spray gun, I guess there's going to be a fair bit trial and error, and really I should have practiced on some spare panels first .



Sicskate said:


> I've never seen runs like that before?!?
> 
> But as above, well done for having a go


I guess it's as above, 'slightly' too much clear coat, it just looked really 'wet' when I applied but obviously the reason being it was really wet!



Aaran said:


> keep an eye out for solvent pop dropping that much clear on in one go.


Solvent pop? Could that be what's caused the bubbles?

So for my next attempt at painting, I'm thinking that less paint but more coats would be the answer?


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## Sicskate (Oct 3, 2012)

Start learning about the stages of paint, so primer first. 

In reality you shouldn't have primed right up to the edge of the masking tape. 

Also, you probably didn't need to lay the colour over the whole area. 

But your learning, no ones expected to get it right first time.


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## Kiashuma (May 4, 2011)

About 110% better than when i tried. Looks fine, i would be happy with that if i had done it myself.


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## Lugy (Nov 4, 2009)

It definitely is quite a different animal from aerosol tins! Currently I've been using U-Pol grey primer from an aerosol, I was under the impression that I only had to prime filler and bare metal, and just key the rest of the paint (for the painting the same colour at least), the bit primer at the top of the panel was after some enthusiastic sanding with the orbital, I probably should have taken a bit more time!
I'm just back from picking the car up, before I left the garage I spent half an hour wet sanding and gave it a quick pass with Menz FG400. For the time I spent it's made a world of difference. 
One thing I've noticed are little 'dots' under the lacquer, must be something wrong with the base or maybe a reaction. 
I've also found an old BMW wing in my shed, so I'll have a play about with that sometime soon.


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## Aaran (Sep 18, 2007)

dots are either moisture bubbles or solvent trapped by putting to much on in one go.

observe the tds for drying times between coats and also film thickness. note all times given are based on the temp of the cars body, so if it says 5 mins between coats at 25c, outside a booth your looking alot more like 15/20-mins between coats at say 15c, especially if you dont have the airflow a booth provides


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## mr paint (Jul 11, 2009)

Looks like you sneezed !


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## Lugy (Nov 4, 2009)

:lol:

I had to cut the drops off with a scalpel, no chance of rubbing them down any time soon.

This; http://www.mig-welding.co.uk/spray-painting.htm, has been my nightshift reading this week. Going to have a play about with the wing I found then might see if I can do any better with the passenger side as it's beginning to bubble up.

My main goal is to get enough experience (won't say skills!) to paint my Cavalier when I've finished welding it. It's white which I'm told is the easiest colour to do but we'll see!


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## JCoxy (Dec 21, 2011)

Yeah It's just practice, My paint ran like tree sap when I first picked up a gun, now with a few de nibs and a polish it's good to go, and not being in a booth isn't bad going

I would recommend adding U POL Rocket to your 2K clear, certainly hardens the paint a little quicker, but if you add too much the paint will turn into silly string within 10 mins


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## Lugy (Nov 4, 2009)

Cheers, would the Rocket reduce the life in the spray pot drastically too?


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## mr paint (Jul 11, 2009)

Yes will harden in the pot rapid ! 


Best thing you can do is sit clear and activator on a heater and get paint around 40 deg ish this will help paint flow out and through cure 


1st coat put on med wed ...dosnt matter if dryish areas ...leave a good 10-15mins and let rip ! 



Tommy


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