capecorvette

I am wet sanding bumper down and it is coming out real nice. Now back in my lacquer days we had to add a flex additive to the paint, do we need to do that will 2 stage urethane paint? I would think not because the paint is much more flexible than lacquer.

I have found a few small nicks, what filler can I use to fill in the nicks on a bumper? and lastly, we don't prime these correct? just shoot paint over sanded bumper?

thanks

crazywelder

There are differing opinions on the additive. If you paint the bumper cover on the car, no additive is needed because the bumper won't be flexing and the harder paint surface can be wet sanded and polished to match the body. If an impact does occur the paint will likely crack but it's a worthwhile risk for the improved appearance. If you paint the part off the car you should put additive in the clear only, since you will be flexing the part during installation and handling. The additive eventually hardens over time so there is little advantage. The additive will also prevent you from polishing the paint as well as the body.

There are several brands of fillers, I use Transtar Plasto-Mend Plastic Repair Non Rigid, it works very well. I also use Transtar Hydroflex Waterborne Primer. It improves adhesion, is flexible and is compatible with all topcoats. It also allows you to fill and sand small scratches and chips and you can block sand the surface similar to body primer. Make sure to follow the tech sheet carefully for sandpaper grit and don't rush the applications.

Scott Marzahl

I wet sanded ours down and sealed with SPI epoxy primer. SPI said no flex agent needed, not even for the clear.