Hi Guys.

A friend has a daily driver type car. A bit scruffy so it's not worth taking it down to the metal etc.

What I'm planning on doing water based cleaner, wax and grease remover, a PPG spirit based cleaner/wipe then 800 grit sand paper over the area. Then the PPG Deltron red base, then three coats of clear.

My question is, is it OK to put the red base coat directly onto the old sanded red?

Thanks for your assistance.

i would prime it with a good 2 part primer what MIGHT happen is the new base will start to lift around any of the broken feather edges where you sanded through during the repair. remember to blend out each coat of the color in med. coats ( don't apply real wet) i'm thinking you're going to sand the complete panel with the 800? if so after the color coats simply clear the complete panel. here's my procedure, apply color to the repair area only with a light coat, let flash then another light coat. after this flashes apply a mid. coat to the repair area and out past a few inches then if coverage looks good apply another med wet coat bringing it out further and dusting the panel as it fades out. now clear. this is a solid color so its not real technical.
Jay D.

Where is this "spot" repair?

What is the damage that you want to fix? Apart from being a "bit scruffy"?

Agree with Jay, badsix, spray a sealer or primer mixed as sealer over the sanded area of the repair before spraying your new base. Real easy and almost foolproof way to avoid disaster if the old base or clear decide they don’t want to play nice with each other. Trick is going to be spraying everything including the sealer in at least 2 light coats so you don’t run the risk of too much solvents attacking the old paint. Follow his advice on spraying the red base out a little further each time until you get into unsanded original color. I’m not sure 3 coats of clear is going to be any better than 2 coats unless you plant to wet sand and buff afterwards but since the rest of the vehicle is “scruffy” I wouldn’t do that and make your new panel look substantially better than the rest of the vehicle

Thanks Guys. I once read somewhere... that a very thin coat of clear over the sanded area increases or improves the adhesion of the base coat. I didn't really want to do a sealer and was hoping to do light coats of the red to match the existing red.

Chris, it's a Holden stationwagon that the front right mudguard has had something spilt on it.

Bill911 wrote:a very thin coat of clear over the sanded area increases or improves the adhesion of the base coat

Every second car on the road and almost every single one more than 10 years old has the clear delaminating from the base. One is urethane based and the other is a modified acrylic. They can't get them to stick together in the factory and now someone wants to introduce another point of failure?

Some more detail on the damage would have helped but, if it's just discolouration on the surface then you're probably ok to simply rub back, without going through the clear, and spray the new base straight over.

As Jay suggests, the weak point is always the feathered edges where the solvent in the new base can seep underneath and cause wrinkling. So, if you have to sand through any layer it's best to cover that with some primer. Only need to do the damage area, then sand with P800, ensuring you block the edges well. Then base coat, blending out towards the edge of the panel, finally clearing the whole guard.

If the damage was small and down near the front of the guard, say close to the headlight, you could just do a SMART repair there and finish it maybe 300-400mm back. If you haven't done this type of repair before then best to stick with clearing the whole panel. On a guard it's not much more in materials. Decide, before you paint, where you want to extend the new base to and the blend area. Sand all of that with P800 wet then go to P1200-P1500 wet (or grey Scotch) for the rest of the panel where you will only spray clear.

You didn't actually say that it's a solid red or not. But worth knowing that if it is Sting/Red Hot then Holden did these in 2K Direct Gloss, not COB. Verify on the car.

Some more detail on the damage would have helped but, if it's just discolouration on the surface then you're probably ok to simply rub back, without going through the clear, and spray the new base straight over.

Thanks, yep, this is the confirmation that I was looking for. I've done a similar one on a Toyota Ist that came out looking beautiful. Until the lady scrapped it again.