Paint repair

Daviesmith · 23 Apr 2023

I think they are galvanised. I used this primer https://www.halfords.com/motoring/p...MI1-v2nuPA_gIVpe_tCh0ntgagEAQYASABEgK6sPD_BwE

Old Salt · 23 Apr 2023

If they are galvanised you will be better using something like this

https://www.google.com/aclk?sa=l&ai=DChcSEwi91P7I7MD-AhWG0O0KHcZtBasYABAFGgJkZw&sig=AOD64_0-2Ywvs1VWyrxW2spkbazyWD4Ovw&ctype=5&q=&ved=2ahUKEwikgPnI7MD-AhXERcAKHSK-BpwQ5bgDKAB6BAgEEAk&adurl=

available at Halfrauds and other good stores

JohnD · 24 Apr 2023

If water is getting under the paint, there might be a pinhole from rust or a crack from impact, allowing water to penetrate from the other side. There might be a hollow structure with water inside it.

Some car designs still get shocking rust damage to the sills that you only see from underneath.

Jonny brown · 24 Apr 2023

You need to check if water is getting into the sill ,not sure how to do that on a polo

Mottie · 24 Apr 2023

JohnD said:
Look at the drips and the bumpy surface.

Some kind of previous bodge, surely.

It’s called Stonechip. Does what it says on the tin. You paint over it. Most cars have it on the sills although that car has had a repair in the past and a chunk of filler has come off.

Tetroseal Stonechip Aero Black 500ml

Suitable for all lower body panels vulnerable to stone chipsProvides a rust proof coatingProtects paintwork Provides excellent sound deadening qualities

www.mymotorworld.com

Daviesmith · 24 Apr 2023

Old Salt said:
If they are galvanised you will be better using something like this

https://www.google.com/aclk?sa=l&ai=DChcSEwi91P7I7MD-AhWG0O0KHcZtBasYABAFGgJkZw&sig=AOD64_0-2Ywvs1VWyrxW2spkbazyWD4Ovw&ctype=5&q=&ved=2ahUKEwikgPnI7MD-AhXERcAKHSK-BpwQ5bgDKAB6BAgEEAk&adurl=

available at Halfrauds and other good stores

So would it be... etch primer / filler / etch primer / paint ? . Obviously with a few coats of each.

Old Salt · 24 Apr 2023

That would work. You really need to make sure its dry, I’m not sure why you were able to pop a water bubble unless the primer/filler was absorbing the moisture. Its certainly strange.

Daviesmith · 24 Apr 2023

I also can't understand it . I'm thinking I didn't put enough paint / primer on .
I originally thought it was coming from inside the sill but not sure how likely that is . What to you think about squinting waxoyl into the sills through the drain hole ?

Old Salt · 24 Apr 2023

I used waxoyl on my classic, worth the time, mess and cost if you are keeping the car for any length of time. Run the car over a tarpaulin before though as it can drip out of odd places. Warm the cans in warm water to help it run.

Jonny brown · 25 Apr 2023

Forcing wax oil into the drain hole from the sills ? Will that not lock any moisture inside? Or will it drive it out ? .

Belle427 · 25 Apr 2023

Jonny brown said:
Forcing wax oil into the drain hole from the sills ? Will that not lock any moisture inside? Or will it drive it out ? .

A good flowing wax designed for cavities will drive it out.
I don’t really rate Waxoyl, there are far better products such as Dinitrol and Bilt hamber available.
I have seen thicker type coatings used on car sills so it may not be filler on yours.