Bodywork over Dp90 Questions...

[Taylor1969]

A warning about DP epoxy primer. You mention there is one coat of DP sprayed on the car. One coat isn't enough! If there isn't enough DFT (dry film thickness) then it would be advisiable to remove the DP by using an orbital sander with #80 grit sandpaper to provide "mechanical adhesion" for filler work.

The DP needs to have a minimum DFT to prevent moisture bleed thru. Best to check an area by sanding. If you happen to see rust underneath the DP, then I would advise you remove it since there isn't much material anyway.

Otherwise, if there was enough DP material applied, you need to scuff the DP where you will be applying filler to aid adhesion. Also, it would be wasteful to dust on a coat of DP over the bodywork area because moisture would bleed thru it. If you plan to spray DP to prevent environmental attack on the bodywork, you must apply at least 3-4 wet coats of the DP to achieve the desired protection.



I would also suggest you acquire a product bulletin to gain more knowledge about the use and "how not to use" DP primers.

Sorry - I shouldn't have said one coat. I meant one application - consisting of two wet coats as reccommended by the DP90 product sheets. It takes some eblow grease to get down to metal at this point. In areas where I plan to apply filler it will be scuffed and/or taken to bare metal depending on what type of repair needs to be made. Thanks for the clarification Alchmist.

[Alchemist]

Your welcome!

When you're ready to spot prime your bodywork, be sure to thoroughly scuff all surrounding DP areas with a red scotchbrite pad, or scotchbrite the entire car if you're gonna prime the whole car/part.

[Taylor1969]

Your welcome!

When you're ready to spot prime your bodywork, be sure to thoroughly scuff all surrounding DP areas with a red scotchbrite pad, or scotchbrite the entire car if you're gonna prime the whole car/part.

THanks for the help!

One more thing. If I plan to run in dp90 and then clear over it what should I sand to before applying the last coat of dp? 320?+

Also - how long is it safe to leave the bodywork in the elements before applying primer to it?

[Alchemist]

Taylor,

What is the result you want by spraying clear over the DP - protection perhaps?

Epoxy primers do not need to be clearcoated to provide environmental protection. Eventually the UV rays will affect the "look" of the DP90, it will start to appear chalky but it will not affect the properties of the DP. As I already mentioned you will need to apply enough coats to achieve the required DFT. When the DP appearance starts to look blotchy, you can sand the DP with #400-600 grit sandpaper and then apply a couple of more coats of the DP90 and it'll look real nice once again.

I've clearcoated DP90 many years ago and it didn't hold up that well! DP primers or I should say "epoxy primers" were meant to be DTMP (direct to metal primer). This is the foundation of a paint job. PPG even suggests that you apply body filler over "sanded/scuffed" DP, even prior to priming.

I would suggest that you get all the bodywork, priming, blocksanding done. Then when you're at the stage just prior to spraying topcoat color, which is where you've final sanded with #320/400/500 grit sandpaper - this is dependent upon the topcoat system (single stage, 2 stage -solid/metallic etc), you can then spray 4-5 very wet coats of DP90 as your barriar coat. Let the DP sit for a few days, then you can wetsand the DP with #400/500, wipe it down and dry it well. Just before you apply your topcoat color, you will need to (and highly suggested) spray one wet coat of the DP90 as your sealer coat, let it flash the recommended time, then blast your color/clearcoat.

This is just one method I've used, using DP epoxy primers.

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http://sem.ws/Catalog.asp?prod=272