As the title implies, are interior panels (i.e. the underside of the hood, inner fenders, core support etc) clearcoated at the factory? I don't believe they are as mine look too matte for that. I'm asking because I have to replace a core support on my truck and passenger fender and would like to paint the core support before installing it. I will probably have a shop paint the fender so they can match it into the rest of the truck.

 

My Focus isn't quite matte in those areas so I think there is some clear coat, especially on the jambs, but a 2009 Charger that I saw definitely was not clear coated under the hood, the trunk or the jambs.

 

Many of the newer vehicles have a cheaper version of the exterior paint on the inside of the vehicle. Not sure why they went this route. But it was mainly used on stuff with either high metallic, 3 stage paint or pearl coats (which are mainly 3 stage). You have to look at your sticker or plate that has the paint code info on it. You can tell from that if there was a different paint used.

 

They're called underhood colors. Almost always a single stage product not requiring a clearcoat. I'm sure other brands can do it to, but a PPG distributor can look up your paint code and get you the exterior and underhood colors for your vehicle. They usually do the underhoods in a different manner to save cost. Colors are usually milkier. Alot of people when repainting things like a core support or inner fender will buy more of the basecoat that they will be using on the exterior and simply catalyze it with and spray it on the underhood pieces. Then spray uncatalyzed and clear the exterior. Basecoat can be catalyzed and used underhood with no clear because it is not exposed to UV. Hope that helps. If you post your paint code I can give you the PPG code for the underhood.

 

GREAT Answer! But, could you clarify what you meant by catayzing the basecoat? The answer is missing some words I think. In my experience you don't cat base, you just mix it with reducer and it air dries.
Thanks.

 

Yep, I left out some important words, sorry. Catalyzing basecoat causes the basecoat to be much stronger. Many companies offer a catalyzed basecoat, some of them having a "reactive reducer" that both thins and catalyzes and some providing a seperate catalyst as an option. Most companies have gotten away from the reactive reducers because of a pretty short shelf life. Also because if you reduce your basecoat and don't use it all, it will go bad. PPG offers a product called DX57 that can be added to DBC basecoat. Its always a better idea to catalyze basecoat. You figure, you catalyze your bondo, your primer, your sealer, your clearcoat.....but not base. Technically its a weak link. Especially if you cut and buff your car and sand through the clear. Repairing that spot can cause wrinkling of the basecoat, making a guy pretty frustrated. Catalyzing the basecoat in an underhood situation causes it to be resistant to chemicals and provides a longer life. However, on the exterior, most of the time catalyzing the basecoat is not needed.

 

DO you sell paint, or rep product, for a living by any chance?? Pretty technical stuff there!
I have to disagree with catalyzing basecoat - but regardless, sounds as though it's not easy to find the product anyways. In all my years I've never seen base catalyzed and have also never seen it wrinkle when repaired....
But in the intertest of the OP getting decent info, I think you'd agree he should just do what MOST EVERY shop does: spray base under the hood and shoot one coat of clear over it. They do this to save time and product (read: money!) and becuase it won't be buffed, so no need for extra clear.
Cheers!

 

Its actually very easy to find. Mostly because its required by the higher end paint manufacturers for warranty purposes. Sherwin Williams is called UH-904 I think, Dupont's High end Basecoat, Chroma Premier is catalyzed. In fact, here's their info:

ChromaPremier® Basecoat is a high-performance, fast-drying, isocyanate-activated basecoat that brings a new level of productivity to premium spot, panel and overall repairs. High-hiding ChromaPremier® Basecoat lays down smoothly, with trouble-free application and excellent mottle control. It delivers superior appearance in solid, metallic, pearlescent and special-effect ChromaLusion® Colors.

And here is a piece off of the tech sheet for PPG's DBC basecoat:

CAUTION: DX57 basecoat catalyst must be added when DBC is used in any of these ways:
In all tri-coat systems (both ground and midcoat layers).
See Clearcoating section note for recommended clearcoats.

The reason for this is because when basecoat is applied on normal colors it is very thin. When it is applied as a tri-stage (pearl whites, pearl reds, some pearl blues) it is thicker and therefore weaker. Adding basecoat catalyst makes it stronger and warrantyable by PPG. I believe this also kind of proves a point, its better. But like I said, not always needed. I would be pretty amazed if you've never seen base wrinkle...ever. I can prove that it will easily, any brand. Paint a panel, clearcoat it. The next day, come back with some 600 on a d.a. and sand through the clear. Mix up some base and spray over the spot. 80% of uncatalyzed basecoats, no matter the brand, will wrinkle. 100% of catalyzed basecoats will not wrinkle. Not trying to beat a dead horse, but it is better. However not always needed.

In the poster's decent info part, I would go one step further on making his life easier. Mix the clear with hardener and then mix it with unreduced basecoat. Spray it on directly like that. I have a Chevy dealership that does it underhood and in door jambs and it works amazingly well. PPG even has a tech sheet on the process. The flat basecoat deglosses the clear a little giving it an almost factory sheen. If anything its a little glossy.

 

Now THAT is a great idea! I do a lot of resto's for myslef and others and that method could be useful and could look just right. Thanks for sharing your expertise!

 

Seems like some solid tech info here. I don't have a lot of auto painting experience. I've painted heavy equipment before with what I think is enamel paint. At any rate, my truck is a 97 F250 hd. I'll have to see about getting my paint code for you; the color looks like what Ford called Toreador red on the super duties, it's basically a metallic looking maroon. I know I'm not up to fading the panels on the outside and making them come out right, but I think I can handle the inside of the panels. For the most part the finish on the truck is still shiny and excellent. I need to also do some work on the tailgate. I'm just trying to keep the old girl looking good. I probably won't get to this til next summer since I don't have a garage or barn to work in. Hopefully my radiator doesn't fall out before then.

 

No problem. If you want to post the code I'd be happy to see if I can find the underhood color number for you.