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· drunk and bored
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Discussion Starter · #1 · (Edited)
This is an article to show,in my opinion,the proper way to smooth the plastic interior
pieces in your vehicle.My main concern here is for you to fully remove the texture to your plastic
and then remove the scratches left by that process.

Plastic adhesion promoter will be use for this project,as will ppg primer.

I will also make use of differents grades(grits) of sandpaper,these being 80 grit and 180 grit. before primer.

The pieces i am demonstrating on are the doors from 1999 GMC Jimmy overhead console.

The first step is to remove all contaminants such as:any interior dressing,fingerprints,nicotine stains etc...
If these contaminants are not removed prior to sanding,they can actually be forced into the scratches created by your sanding.I use multiple steps to remove contaminants.These consist of warm soapy water,wax and grease remover and my favorite is original formula WINDEX!

Clean your parts thoroughly and then follow along.

I start with 80 grit sandpaper,and sand out the texture.There is no need to use a sanding block,just use the ball of your palm.

Feel free to use your finger tip on the edges.

Sand in opposing directions...i.e....crosshatch.Check your work frequently,sometimes you may need to clean your part to check your progress.Remember,you want to remove all texture!

Filling the texture with primer is a no-no.....it can be done,but there remains a possibility(inevitability) of potential shinkage or failure.

Here you can see the differences sanding does:


remember,we want to REMOVE the texture as in the upper right of the piece.

I make sure that i get the edges very,very good....i even remove just a tad bit extra material knowing that there will be a fair amount of new material applied.

The discolored oval is where i wiped it to check for texture removal...we want it to look like that.

This piece is part of this console that is already finished.

Interested yet?

This piece is not even ready for 180 grit yet....if you look closely you can still see small pits left in the plastics texture,you can also see the 'cross-hatch' pattern i referred to

remember...removal of all texture is key!

now that the texture is removed,it is time to remove the 80 grit scratches that was created by that process with 180 grit.....when the 80 grit scratches are removed(you can tell)....

it is time for prepping for primer:

This is one of my favorite pre-paint cleaner!It get's mixed:2 parts water,1 part Total Prep,put in in a spray bottle.Make sure to shake it up everytime you use it!
Spray on your part and dry off with paper towels or some kind of prep towel.
(i said DRY OFF not wipe around and let it evaporate)

if this step is not followed contaminants can be left behind

this is ppg's newest plastic adhesion promoter,one light coat followed by about 15 minutes flash time

since i was spraying something else at the time,i hit it with a coat of ppg dp-90 epoxy(not necessary,but it does not hurt a bit)

after a 30 minute 'flash time,it was time for primer.i used ppg's k-36...i applied 2 coats with 15 minutes flash time in between,keep in mind it was 95 degrees when i was spraying.

there ya go.....the black paint dusted on top is called a guide coat,it will allow you to see imperfections in the primer as you sand

being as there are so many paint manufacturers,i am not going into detail on paint prep.

your tech sheets for your paint system will tell you most of what you need to know.

the hard part is done,the plastic has been completely smoothed and there is very little possibility of shrinkage.
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