Paint Question

[Kaput 705]

Hello All - I just painted the underside of a hood of a stock car model I received and this happened: (see attached photo). Dupli-color perfect match over rustoleum primer. The car body is actually fine its just the hood part. Any thoughts before i run it over with the lawnmower? Lol 

[StevenGuthmiller]

Just a guess, but I’m gonna say “Rustoleum” is your problem.

Strange how that name comes up with about 90% of paint issues.

 

 

Steve

[Bainford]

It looks like the classic reaction when painting lacquer over enamel. I am guessing the Rustoleum primer is enamel. Curious it didn't happen to the rest of the body.

[Fat Brian]

I agree with the other posters, this is pretty classic paint incompatibility. Use Duplicolor primer under Duplicolor paint and it will greatly reduce the chances of this happening. 

[Kaput 705]

Got it. Thanks everyone yeah i honestly used what i had on the shelf i am in no way a pro at this. Appreciate the responses

[Shark]

I don't use Rust-Oleum primers anymore. Had to spray them very light and they had a tendency to cure slow.

[peteski]

If the top surface of the hood and the entire car body were painted with the same exact primer and color paints I find what happened very weird. Unless maybe you sprayed the underside of the hood with a very heavy wet coat of the top color paint, but used lighter coats on the other (undamaged) surfaces??

Edited October 2, 2024 by peteski

[yh70]

i use Rust-Oleum primers all the time with no problem, but i use Rust-Oleum paints over the top. if you use Dupli-color paint , use Dupli-color primer. same as tamiya paints and so on. use the primer to match the paint. dont get me wrong here im guilty of using the wrong primer and got lucky. lol

[slusher]

Duplicolor paint need Duplicolor primer.  It’s a hot paint.   Strip your hood and repaint it body looks good!

[StevenGuthmiller]

This is why you throw everything else in the trash and use a good automotive lacquer primer for EVERYTHING!

There's absolutely no need to have a half dozen different primer brands laying around for this, that, and the other thing.

One good primer can be used under any type of paint, and you won't have to ever deal with this sort of nonsense again.

My go-to is Duplicolor sandable primer, in several colors, and Duplicolor primer sealer.

Of course there are others, but find one that's intended to withstand automotive lacquers and stick with that, and that only.

Bouncing around between a bunch of different products is almost guaranteed to create issues at some point.

 

 

 

Steve

[Dave G.]

I don't use enamel primers for anything. And Rustoleum primer is enamel. I bought exactly one can with stipulation if it wasn't lacquer, as the store employee said it was, I could return it. I shot one little spritz of paint and returned it. I know the smell of enamel primer from years ago, Got my money back. I'll use enamel color coats but not primer.

[Fat Brian]

I agree with Steve, just use Duplicolor primer and you shouldn't ever have this problem again. I've shot about anything you can think of over it without issue. Even actual car paint from an autobody shop near me that mixes cans went over it just fine.

[StevenGuthmiller]

3 hours ago, Fat Brian said:

I agree with Steve, just use Duplicolor primer and you shouldn't ever have this problem again. I've shot about anything you can think of over it without issue. Even actual car paint from an autobody shop near me that mixes cans went over it just fine.

Exactly.

You just have to have a basic understanding of how these things work, and once you understand the fact that automotive primer is basically impenetrable by anything you care to throw at it, I just can’t understand why anyone would roll the dice with anything else.

Makes zero sense to me.

 

 

 

 

Steve

[Bugatti Fan]

It comes back to the very basic rule of thumb.

Oil based paints over Acrylic generally works OK.   But not the opposite way.

Why ?   Acrylic paint forms the equivalent of a thin plastic coating when dry and therefore a seal. Oil based paints used underneath cannot evaporate naturally and therefore will attack the acrylic from underneath

The make of  paint is probably not as important as following the basic rule of acrylic under not over.

 

Edited October 3, 2024 by Bugatti Fan

[Rocking Rodney Rat]

Use Duplicolor DAP-1699 primer. You won't have any issues. -RRR

[bobthehobbyguy]

I think this is a gtrat illustration of the issues caused by mixing paint brands. My guess is that you may have painted the hood a little wetter and got the reaction. Staying with one brand of paint and paint type when painting.

[StevenGuthmiller]

2 hours ago, bobthehobbyguy said:

I think this is a gtrat illustration of the issues caused by mixing paint brands. My guess is that you may have painted the hood a little wetter and got the reaction. Staying with one brand of paint and paint type when painting.

Brand is much less important than the formulation of the primer.

As I said, you can spray anything over a good automotive lacquer primer such as Duplicolor, whether that be an enamel from Testors or Rustoleum, a lacquer such as Duplicolor, Tamiya, MCW, etc, or a water based acrylic.

Doesn't matter.

If you rely on brand, it requires that you have a bunch of different primers laying around if you use various paints.

It's not necessary.

All you need is one.

 

Even the "brand" theory can cause problems if you're not paying close attention.

Some brands carry lacquer primers and enamel primers, as well as lacquer and enamel paints.

I certainly wouldn't risk spraying a lacquer over enamel primer, even if it is the same brand.

 

 

 

 

Steve

[Bainford]

55 minutes ago, StevenGuthmiller said:

Brand is much less important than the formulation of the primer.

As I said, you can spray anything over a good automotive lacquer primer such as Duplicolor, whether that be an enamel from Testors or Rustoleum, a lacquer such as Duplicolor, Tamiya, MCW, etc, or a water based acrylic.

Doesn't matter.

If you rely on brand, it requires that you have a bunch of different primers laying around if you use various paints.

It's not necessary.

All you need is one.

 

Even the "brand" theory can cause problems if you're not paying close attention.

Some brands carry lacquer primers and enamel primers, as well as lacquer and enamel paints.

I certainly wouldn't risk spraying a lacquer over enamel primer, even if it is the same brand.

 

 

 

 

Steve

Exactly. This has nothing to do with paint brands, and everything to do with incompatibility of paint types. If the primer on this model was painted over with any other brand of enamel, there would likely have been no problems. Similarly, if Rustoleum made a lacquer paint, and it was applied over Rustoleum enamel primer, this reaction would likely occur.

There is absolutely nothing wrong with mixing brands. Many of us do it all the time with excellent results. It is perfectly acceptable to do as long as one has a basic understanding of the different paint types, which, for hobby purposes, is not at all complicated (this statement ignores the introduction of two-part or 2K paints, which I won't comment on except to say, best just to avoid it altogether for hobby use). For example, Duplicolor primer, covered with Tamiya lacquer thinned with Mr Color levelling thinner, and cleared with Alclad works great. The key is that they are all lacquer compatible, and the combination was tested beforehand. Once a little experience is gained, one can move forward with confidence.

As Steve mentioned, a newby who finds himself confused by all this paint stuff and 'plays it safe' by selecting all Tamiya products may find he has a frustrating and discouraging mess on his hands, since Tamiya markets acrylics, enamels, and two types of lacquer paints. A potential quagmire of incompatibility.

It is important to understand the basic issues (they are not difficult), and not just blindly choose products because they are the same brand. Additionally, instructing others to 'stick to one brand' stifles experimentation, which is a fun and interesting aspect of our hobby, and has led to some excellent discoveries over the years that many of us now take advantage of. The key is to test before committing to a kit. Also, screwing up the paint on a kit is not the 'end of the world' event that some people make it out to be. Just chalk it up to experience, strip it and move on.

[Bills72sj]

Here is a link to a lengthy demo of the Duplicolor primers.

 

[StevenGuthmiller]

19 minutes ago, Bills72sj said:

Here is a link to a lengthy demo of the Duplicolor primers.

 

Thanks Bill.

I’ve often tried to convince people, especially the Tamiya faithful, that nobody makes a better spray can nozzle than Duplicolor. ?

 

 

 

Steve

[Rocking Rodney Rat]

23 hours ago, StevenGuthmiller said:

nobody makes a better spray can nozzle than Duplicolor.

I don't like the spray nozzle on Duplicolor primers at all. Frequently, the nozzle will depress and not come back up. When that happens, I go to O'Reilly's and buy a new can and take the receipt and the old can back and get another new can. -RRR

[StevenGuthmiller]

2 hours ago, Rocking Rodney Rat said:

I don't like the spray nozzle on Duplicolor primers at all. Frequently, the nozzle will depress and not come back up. When that happens, I go to O'Reilly's and buy a new can and take the receipt and the old can back and get another new can. -RRR

That’s strange.

I’ve been using Duplicolor primers as well as their paints for decades and I’ve never had that happen.

Not once!

I’ve had very limited occasions where I’ve had damaged nozzles or plugged cans that wouldn’t spray at all, (had that happen with every brand of paint I’ve ever used) but I’ve never had one stick in the depressed position, even with cans from this vintage. (some of which I still have)

 

 

 

 

Steve

[peteski]

I have to say that I also experienced the metal plunger rod get stuck in a depressed position.  You must be lucky Steve, or couple of us are just unlucky.

[StevenGuthmiller]

6 minutes ago, peteski said:

I have to say that I also experienced the metal plunger rod get stuck in a depressed position.  You must be lucky Steve, or couple of us are just unlucky.

Apparently my luck has been holding for a looooong time.

Just seems odd as I would expect that if the rod is stuck in the depressed position that the paint wouldn’t stop spraying.

If it’s just a little sticky and sticking somewhere in the middle, with the exposed rod would be pretty easy to lubricate and get ahold of with a needle nose to work it loose again.

But, I wouldn’t know because to the best of my memory, I haven’t seen it since I started using Duplicolor products back in probably the mid 80s.

 

 

 

 

Steve

[deuces wild]

I have Dupli-Color spray cans that I bought in the late '90s... Hope they are still good...???