Painting Undercoat

[adivin]

My 72 240Z must have dealer installed undercoating in the wheel wells.  I'm not sure if they did this at the factory.  I am (my Dad) the original owner.  Can this undercoating in the wheel wells be effectively painted?  I don't want to remove it and it makes no sense to put more undercoating or bed liner on top of it.  I'm wondering if paint will adhere and not flake off easily, or would this be a waste of time?  Any suggestions for what to use, or just leave it?

[Diseazd]

Adivin.......The factory installed undercoating in the wheel wells holds paint just fine in my experience. It’ll look great IMO.

[adivin]

3 hours ago, Diseazd said:

Adivin.......The factory installed undercoating in the wheel wells holds paint just fine in my experience. It’ll look great IMO.

Thanks, have you found it stays on even after even after several miles of dirt and debris kicked up from driving?  I can't decide if I want to paint black or the color of the car (112) under there.

[Diseazd]

No problems.......still perfect.....go for it!

[jfa.series1]

Here's another before  and after, all in body color. I prepped and finished this area before my car went off to the painter.

[Racer X]

On 10/2/2020 at 5:20 PM, adivin said:

My 72 240Z must have dealer installed undercoating in the wheel wells.  I'm not sure if they did this at the factory.  I am (my Dad) the original owner.  Can this undercoating in the wheel wells be effectively painted?  I don't want to remove it and it makes no sense to put more undercoating or bed liner on top of it.  I'm wondering if paint will adhere and not flake off easily, or would this be a waste of time?  Any suggestions for what to use, or just leave it?

Be sure to clean and prep the surface very well. Solvent and a stiff bristle brush, followed by a thorough scrub with another stiff bristle brush and soapy water. Rinse well, and be sure to get the surface clean deep into all the irregularities of the undercoating. Adding a flex agent to the paint applied to the undercoating would be a good idea too, so the paint will be more resistant to chipping from stones and grit thrown around by the tires.

[qz16]

I’m not the most experienced painter, so take that into account when you read this.  I am restoring a 1973 240z, changing colors so everything needed to be painted.  One thing that I learned is that I am not capable of defining where rust is or is not.  I wound up removing undercoating from places that I would have bet would not have rust only to reveal issues that I might have inadvertently covered up if I had not taken the time to remove the original 43 year old covering.  I also learned that I could not get away with covering something unless it was completely free of dirt, oil etc.  In my case I had to remove fenders anyway and once I started chiseling and using a wire wheel I could not stop.  I originally was going to make it body color, but my paint color (orange) is extremely expensive, and I actually liked the blacked out look better.  A friend criticized my flat black approach and he was right.  I sprayed a rustoleum  rubberized undercoating product over the flat black and I like the result.  It actually looks better than the picture.  The bucket has not gotten back on the road yet so I cant tell you how well it will hold up but it is reasonably thick and seems pretty tough. 

 

By the way I would encourage you to take a really good look at what is covering the floors inside the cabin, I had what I believe was a factory coating inside,  AND the undercoating on the underside of the car.  I found areas where for whatever reason: driving over a curb or a poorly placed jack, or a mean spirited rock chipped the undercoating.  I think what happens is that water gets into the crack actually gets between  the coating and the metal.  Overtime rust is generated and for the most part concealed from most eyes.  The dog leg area is notorious as is the floor pans just before the firewall, and of course where the fender meets the lower corner of the door.  Free advice probably worth as much.