Front and rear grill plastic questions

[pagrunt]

I'll add if possible (and if offered in the paint line you're using) use flex additve for the covers. One thing to note is it's most likely the paint is laquer so that adds to other things to keep in mind for what can work over it as not all paints like each other. As for those cracks, it is from the laquer cracking & exposing the fine line of the bumper's urethane to the elements. Those can be covered/filled with thin coats of plastic bumper repair from 3M, Lord Fusor & Upol. Like as Rktpwrd & 57 Handyman both brought up, fine sand paper & not getting heavy on the sanding, just something to allow the paint to get a bite after cleaning things up. In an opposite from some of the advice & this comes from old school body guys I used to deal with, sometimes it is not needed to remove all the old paint but think about how the new paint type will react to the old/unkown type of paint. One other thing is try to set up a jig to hold the covers in the right shape to ensure the repairs are smooth & not wavy from them always flexing while working on them.

 

[Tony1968]

I'll add if possible (and if offered in the paint line you're using) use flex additve for the covers. One thing to note is it's most likely the paint is laquer so that adds to other things to keep in mind for what can work over it as not all paints like each other. As for those cracks, it is from the laquer cracking & exposing the fine line of the bumper's urethane to the elements. Those can be covered/filled with thin coats of plastic bumper repair from 3M, Lord Fusor & Upol. Like as Rktpwrd & 57 Handyman both brought up, fine sand paper & not getting heavy on the sanding, just something to allow the paint to get a bite after cleaning things up. In an opposite from some of the advice & this comes from old school body guys I used to deal with, sometimes it is not needed to remove all the old paint but think about how the new paint type will react to the old/unkown type of paint. One other thing is try to set up a jig to hold the covers in the right shape to ensure the repairs are smooth & not wavy from them always flexing while working on them.

Excellent advice. Thank you.

 

[Rktpwrd]

Donovan. The upper plastic around the headlights etc is a much harder plastic. The lower is the flexible stuff. Looking at pictures and I created a small divot in hard plastic. Not huge as I'm pointing to it but definitely feel it. My mistake. So now I'm trying to figure out what I can fill it with. I'm searching but not coming up with definite answers.
Also if you look where the cracking was after I removed paint you can still see cracks in bare plastic. Is there something I can use for both as filler? I have 2 part 3m glaze but it doesn'tspecifyuse on plastic View attachment 229189 View attachment 229190 View attachment 229191

Sorry for the late reply, but this is literally the first chance all day I’ve had to respond. I don’t get many opportunities during the workday and week to respond.

The guys above have it right, all their suggestions and comments are spot on. To answer your specific question about your plastic repair, you’re going to have to try and determine what type of plastic it is if you can. As noted above, Lord, Fusor and 3M all make plastic repair compounds, and each manufacturer will have different compounds for different applications. As I’ve mentioned before, I’m a 3M fan, so the 2 I currently have on hand are these:

The one on the right is compatible with SMC (sheet molded composite) that the header panels on our cars is made with, and the one on the left is supposedly compatible with almost all plastics. I’ve used both successfully in different applications. The one real disadvantage to the universal repair compound on the left is the EXTREMELY short work time. Only 20 seconds. 😮 Others may be different.
That being said, it’s worked well on ABS and other plastics I’ve used it on.

pagrunt ’s description of why the crack outlines are still visible even after the paint has been removed is bang on. I couldn’t have described it better myself. My reasoning for stripping off all the old paint is as he outlined, because of compatibility issues with the base paint which is most likely lacquer. The high solvent content of the new paints will eat into the lacquer paint (which isn’t catalyized by the way) causing reactivity issues if it’s not completely removed first, or insulated with epoxy primer.

Hopefully this helps clarify things a bit for ya.

 

[78Delta88]

If you are going for decent proper restoration..., all of that, is just like the Trans Am nose, spoiler, and flares are to be painted with urethane paint.

You do not sand those pieces....

You use chemical stripper.

You need to find older body and paint specialist.

I think the one to use is the aviation stripper, don't remember the particular brand.

 

[Tony1968]

Sorry for the late reply, but this is literally the first chance all day I’ve had to respond. I don’t get many opportunities during the workday and week to respond.

The guys above have it right, all their suggestions and comments are spot on. To answer your specific question about your plastic repair, you’re going to have to try and determine what type of plastic it is if you can. As noted above, Lord, Fusor and 3M all make plastic repair compounds, and each manufacturer will have different compounds for different applications. As I’ve mentioned before, I’m a 3M fan, so the 2 I currently have on hand are these:

View attachment 229251

The one on the right is compatible with SMC (sheet molded composite) that the header panels on our cars is made with, and the one on the left is supposedly compatible with almost all plastics. I’ve used both successfully in different applications. The one real disadvantage to the universal repair compound on the left is the EXTREMELY short work time. Only 20 seconds. 😮 Others may be different.
That being said, it’s worked well on ABS and other plastics I’ve used it on.

pagrunt ’s description of why the crack outlines are still visible even after the paint has been removed is bang on. I couldn’t have described it better myself. My reasoning for stripping off all the old paint is as he outlined, because of compatibility issues with the base paint which is most likely lacquer. The high solvent content of the new paints will eat into the lacquer paint (which isn’t catalyized by the way) causing reactivity issues if it’s not completely removed first, or insulated with epoxy primer.

Hopefully this helps clarify things a bit for ya.

Yes it clarifies totally. Thank you!

 

[LeftLaneOnly]

maybe a bumper wrap would work