Repainting Interior Plastics

Anything goes in the world of fiberglass and plastic



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PostPosted: Sat Jun 07, 2014 11:03 am
HI

I'm currently refinishing some plastic pieces in my interior. They were painted blue by the previous owner, but are starting to flake off.
Coulple questions:

The pieces have been stripped with a plastic safe stripper (well it did melt a couple pieces). Do I need to completely remove all the paint? There are bits that the stripper didn;t remove.

Also wondering what grits I need...I know there's a sticky, but I'm not sure if its the same with plastics. Any tips on sanding plastic?

I;m using a plastic adhesion promoter, primer surfacer with flex, acrylic enamel (no flex), and clear coat with flex.

Will the lack of flex in the acrylic be a problem? It's a metal flake paint.

Sorry if these are stupid questions...
Thanks

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PostPosted: Wed Jun 11, 2014 6:43 pm
The base is thin enough you will be fine without flex agent. You don't have to strip completely just make sure it's feathered out good and primer over everything. If sanding start with 100 grit or higher, see how it goes. Coarse grits tend to "fuzz" the plastic, you just need to be careful.



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PostPosted: Mon Jun 16, 2014 1:17 pm
chris wrote:The base is thin enough you will be fine without flex agent. You don't have to strip completely just make sure it's feathered out good and primer over everything. If sanding start with 100 grit or higher, see how it goes. Coarse grits tend to "fuzz" the plastic, you just need to be careful.



Thanks!

Just wondering about sanding... I'm using 400 grit wet after stripping the old paint. Wondering if I should use a sanding sponge or a sanding paste instead. I want to make sure everything is nice and smooth. should I be more concerned with smoothness during the priming stage?



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PostPosted: Tue Jun 17, 2014 8:21 pm
If the coating was done incorrectly and failing it all has to come off. It's flaking so the previous person had no refinishing knowledge. Check out SEM Products. It's usually what I've used in years of plastic refinishing. That's just one of their professional products available. Priming is not standard procedure. If you are green and have questions just call SEM.

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PostPosted: Wed Jun 18, 2014 7:49 am
Here's the SEM product for priming plastic:

http://www.semproducts.com/flexible-primer-surfacer/

and yes, the primer needs to be flat before you paint...



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PostPosted: Wed Jun 18, 2014 8:12 pm
Chris,
Primer is available but not standard procedure. Generally all that is required is prep, adpro if required (or desired), and shoot. Check it out. SEM is easy to navigate and choose products that apply to a particular job.If not, a phone all to their tech line can provide a novice with assistance.

The OP might also have paint mixed in an interior formula based on his company of choice. Metal flake as the OP states is open to interpretaion. Often people refer to metallics as flakes. Flake sizes vary and can exceed that of metallic in automotive factory paint.

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PostPosted: Wed Jun 18, 2014 8:49 pm
Thanks, Scott - I didn't realize it wasn't considered a typical procedure; I've use similar primer before on "problem" plastics and it has helped. Scuffs, minor scratches, and sanding marks...that sort of stuff.

Never called the SEM tech line but that's a good tip too...thanks...

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PostPosted: Wed Jun 18, 2014 11:44 pm
Interior pieces are tricky because they can be contaminated with Armor-All or some other silicone detail spray. It can make it a real nightmare for interior items.

I like to wash everything really well with warm water and dish soap. Wipe down with rubbing alcohol. On smooth plastic, wet sand with P220 - P400 depending on how much work needs to be done. Even more coarse if it is really rough, and then work my way back up.
If it is textured plastic, a gray scotchbrite pad and scuffing paste is your best bet.
Spray with SEM or Bulldog adhesion promoter and either paint it or prime it and then paint.

On an external item like a bumper, you can usually get by with just epoxy priming and painting over that... Interior items, I like to take the extra step and use adpro for a little insurance.

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