diy repair to aluminium corrosion

[mx5cl]

Hi all

This is my first post on pistonheads so please go easy!

I would really appreciate some advice if possible on a repair I am currently considering.

I have a 2007 mazda mx-5 (seemingly the answer to all known problems / needs on here!!) with some corrosion to the underside of the boot lid near to the front lip. I have owned the car for around 3 years and the "spidering" of the paint has increased by around 50% in that time. I am keen to effect a repair to slow it down at the very least and hopefully prevent it spreading to the outer skin of the bootlid thus avoid an expensive trip to the bodyshop (for the time being at least). Pic below (excuse the camera phone!!):



After garaging the car overnight and blasting with some warm air to make sure its dry I plan to do the following (suggestions / comments welcome):

1. sand back the affected area to bare metal
2. treat with a product to "convert" the corrosion (is this possible with aluminium? i'm aware of kurust for example being used on steel)
3. paint with rattle can (do I need a primer / base coat?)
4. inject some wax in behind the panel through the hole.

Thanks

[jds32]

The way I would do it is like you say then at the primer stage use an etch primer something like upol acid 8 then let it dry then a filler primer. Then paint it and I jet it with wax.

[G600]

Not sure if you could get hold of it once the corrosion is removed I'd treat it with alochrome/ (we use it for aircraft) then prime.

[mx5cl]

Thanks for your responses, really useful, i'd seen this aluchrome stuff mentioned on some yachting / land rover sites, looks quite specialist, not sure I could get it at Halfords!

Does etch primer do a similar job?

[adeel_gt]

Have you tried mazda? There anti corrosion warranty should cover you.

[Evoluzione]

mx5cl said:

Hi all

This is my first post on pistonheads so please go easy!

I would really appreciate some advice if possible on a repair I am currently considering.

I have a 2007 mazda mx-5 (seemingly the answer to all known problems / needs on here!!) with some corrosion to the underside of the boot lid near to the front lip. I have owned the car for around 3 years and the "spidering" of the paint has increased by around 50% in that time. I am keen to effect a repair to slow it down at the very least and hopefully prevent it spreading to the outer skin of the bootlid thus avoid an expensive trip to the bodyshop (for the time being at least). Pic below (excuse the camera phone!!):



After garaging the car overnight and blasting with some warm air to make sure its dry I plan to do the following (suggestions / comments welcome):

1. sand back the affected area to bare metal
2. treat with a product to "convert" the corrosion (is this possible with aluminium? i'm aware of kurust for example being used on steel)
3. paint with rattle can (do I need a primer / base coat?)
4. inject some wax in behind the panel through the hole.

Thanks

Are you sure that is aluminium?

[jds32]

Evoluzione said:

mx5cl said:

Hi all

This is my first post on pistonheads so please go easy!

I would really appreciate some advice if possible on a repair I am currently considering.

I have a 2007 mazda mx-5 (seemingly the answer to all known problems / needs on here!!) with some corrosion to the underside of the boot lid near to the front lip. I have owned the car for around 3 years and the "spidering" of the paint has increased by around 50% in that time. I am keen to effect a repair to slow it down at the very least and hopefully prevent it spreading to the outer skin of the bootlid thus avoid an expensive trip to the bodyshop (for the time being at least). Pic below (excuse the camera phone!!):



After garaging the car overnight and blasting with some warm air to make sure its dry I plan to do the following (suggestions / comments welcome):

1. sand back the affected area to bare metal
2. treat with a product to "convert" the corrosion (is this possible with aluminium? i'm aware of kurust for example being used on steel)
3. paint with rattle can (do I need a primer / base coat?)
4. inject some wax in behind the panel through the hole.

Thanks

Are you sure that is aluminium?

That's a good point actually, I don't think they are now I think about it.

[mx5cl]

adeel_gt said:

Have you tried mazda? There anti corrosion warranty should cover you.

hi, yes tried them a few times they have stuck to the line that it's covered for perforation but it is out of warranty for paintwork

[mx5cl]

jds32 said:

Evoluzione said:

mx5cl said:

Hi all

This is my first post on pistonheads so please go easy!

I would really appreciate some advice if possible on a repair I am currently considering.

I have a 2007 mazda mx-5 (seemingly the answer to all known problems / needs on here!!) with some corrosion to the underside of the boot lid near to the front lip. I have owned the car for around 3 years and the "spidering" of the paint has increased by around 50% in that time. I am keen to effect a repair to slow it down at the very least and hopefully prevent it spreading to the outer skin of the bootlid thus avoid an expensive trip to the bodyshop (for the time being at least). Pic below (excuse the camera phone!!):



After garaging the car overnight and blasting with some warm air to make sure its dry I plan to do the following (suggestions / comments welcome):

1. sand back the affected area to bare metal
2. treat with a product to "convert" the corrosion (is this possible with aluminium? i'm aware of kurust for example being used on steel)
3. paint with rattle can (do I need a primer / base coat?)
4. inject some wax in behind the panel through the hole.

Thanks

Are you sure that is aluminium?

That's a good point actually, I don't think they are now I think about it.

I've been out just now and checked it with a magnet, zero stickage! apparently the boot lid on the folding hard top variant is steel but mine is the rag top. Also if it were steel, would the corrosion not have spread faster?

If it does turn out to be steel, is the repair procedure any different? I've got some etch primer to help a high build primer / filler bond and some paint and lacquer to finish the job off, my main concern with the etch primer is, I presume its nasty stuff to get on existing paint so am I best off decanting some and brushing it on in very light coats being careful not to overlap too much?

Thanks for all your help on this, i'll post some pics up when I start the repair!

[CharlesElliott]

Aluminium will react with water to form aluminium Oxide (white powder) but it is nowhere near as aggressive as rust in steel. I'm surprised that you have as wide a spread as you have if it is aluminium to be honest.

[jds32]

Etch primer isnt that nasty and nothing to be scared of. Just make sure the edges of the repair are feathered out.

Apply the etch primer to the bare metal, then the filler primer covering the etch primer and any deep scratches then the colour over the primer and into the existing paintwork. Then finally the lacquer over the colour.

Obviously there is a bit more to it than that, but thats the general idea.

The repair will be the same regardless of wheter it is aluminium or steel.

[JQ]

Get yourself on to MX5nutz and ask the question there, there are a number of bodyshop owners the forum who are MX5 owners. PainterDave is currently working on a Mk3 as a Project Car.

[mx5cl]

update time!

i've now gone ahead and tackled the corrosion, (camera phone) pics below:

taken back to bare metal (along with patch on other side and one near hinge)


etch primed


and other side


then filler primer, which after being a bit trigger happy was then tidied up with wet and dry!




and finally painted




I've treated in behind with cavity wax (just visible in the last pic) and hopefully that will slow it down at least, time will tell! Needs a bit of a tidy up in places but as it is a secondary surface I'm not too bothered.

Thanks for all your help, certainly got the confidence to have a go at a few more jobs next being a rattly roof latch!