Technical Damn its going crusty..

[Leroypanda]

For non Fiat owners this is very very rare now!

Bottom corner of my drivers door has started bubbling unber the paint, best way to rectify without taking paint off?

 

[jrkitching]

Bottom corner of my drivers door has started bubbling unber the paint, best way to rectify without taking paint off?

Can't be done. You'll need to sand the affected area back to sound metal, fill, prime and refinish as necessary. Be aware the damaged area may be more extensive than appearances suggest.

With care, you can get good results over small areas using a modeller's airbrush, following usual bodyshop practice in miniature. I've seen mobile chaps doing this outdoors on used car forecourts. Easiest with solid colours.

Check the drain holes are all clear. If you plan on keeping the car, consider removing the inner door trim panel and treating the inside with a non-setting wax based product.

For non Fiat owners this is very very rare now!

Even for Fiat owners, main bodyshell paint damage is unusual during the first ten years (the bolt on bits are another story). Makes me wonder if there has been any prior accident damage to the affected area?

 

[Herts Hillhopper]

There must have been some damage repair there. The Panda is (as are most cars in the past ten years) fully galvanised and rust on any body panel is so rare as to be unheard of. But, if it’s been badly scraped (enough to gouge into the metal), then a fill and repaint will often lead to rusting through (because the zinc layer - both inside and out - will have been removed)

 

[Leroypanda]

Think it where its been caught when open doors, as its the bottom leading edge.
Guess ill have to dremel out the grot, zinc primer whats left, fill and respray.

 

[Herts Hillhopper]

If it’s right in the bottom edge then, as @jrkitching said, check the drain openings in the bottom of the doors (rectangular slots where the horizontal and vertical parts meet — there’s also similar drains on the boot lid). If these are blocked then water will pool on the inside of the door and can let rust start from the inside outwards.

 

[mj2k]

For non Fiat owners this is very very rare now!

My first thought was to suggest going to the doctor's for some ointment

Other than that, as above, and well worth checking any other drain holes too (does the Panda have scuttle drains?) in case water's collecting anywhere else as well

 

[irc]

There must have been some damage repair there. The Panda is (as are most cars in the past ten years) fully galvanised and rust on any body panel is so rare as to be unheard of. But, if it’s been badly scraped (enough to gouge into the metal), then a fill and repaint will often lead to rusting through (because the zinc layer - both inside and out - will have been removed)

Even supposedly well-repaired damage is likely to be a weak spot after a while. There is a 15 plate 500 locally which got a long scrape down the passenger side. I know it was repaired by an "insurance approved" repairer as I gave the owner a lift to work while it was being repaired. The rear wheel arch has started bubbling where it was repaired. Shame really, as it looked like they made a good job of the repair.
Slightly off topic, but this wing (ok, it's a 169 Panda) was a "proper" insurance repair. This winter it suddenly sprouted some real rust. Not a genuine part, so even though they did a great job on the paintwork, saving a few quid on the panel didn't work out so well.
The other side looks like new!
(Fortunately I've got a spare genuine wing from a breaker in the right colour)