What am I doing wrong?

[FlyingDutchman]

I'm a relatively new modeler, back at it later in life after some childhood enjoyment. I've been cutting my teeth on car, tank, airplane models trying to round out my skills. Right now I'm really trying to perfect my model car paint job. With this Tamiya 240Zg I've progressed far enough in my skills to wet sand and engrave the panel lines a bit. The highest grit sand paper I have at the moment is 2000 so after taking care of the mold lines with lower grit stuff I mostly wet sanded 1000 and then 2000 over the whole body.  I primed with decanted grey Tamiya Fine primer. I wet sanded that as well. Then I sprayed the body color Maroon  using the color matched paint from Zero Paints. I sprayed right out of the bottle per instructions.  So at this point I'm wondering where I go next. It seems next would be clear coat but I'm noticing all these little micro scratches on the body and not sure if I should be doing something to address those. The pictures below show near the end before my last coat or two where I evened out the paint a bit more. The body is actually a lot smoother than it looks and is very shiny. But swirl marks are everywhere! I'm not sure if I needed a finer grit sandpaper after primer or if this is just normal and some polish will take care of it later?

Can I wet sand the paint before clear coating? Or should I clear coat and then polish and/or wet sand AFTER? Thanks all!

Edited December 19, 2022 by FlyingDutchman

[Straightliner59]

It looks to me like, unfortunately, the paint attacked the primer. Unfortunate, because you'll likely have to strip the body. I am making that assessment, because it looks pretty much like a '53 Corvette, I had that happen to, just a few months ago. There are others here, who may have a better idea, so don't throw it in the purple pond, just yet!

[rmedtr6]

It appears to me that the solvents in the Zero Paints are too hot for the Tamiya primer and have reacted with it.  Best to use the same brand primer as paint whenever possible.

[Bugatti Fan]

I tend to use proper automotive acrylic primer straight from an aerosol. It goes on smoothly and is pretty tough when paints containing more aggressive solvents are sprayed onto it. Some say that using that sort of primer diminishes detai!. So far I have had no problems on that score on my models.

[Straightliner59]

10 minutes ago, Bugatti Fan said:

I tend to use proper automotive acrylic primer straight from an aerosol. It goes on smoothly and is pretty tough when paints containing more aggressive solvents are sprayed onto it. Some say that using that sort of primer diminishes detai!. So far I have had no problems on that score on my models.

That's what I do, too. I've had pretty good luck, through the years, except with the aforementioned '53 Corvette. It was a promo, so I suspect the plastic had something to do with that, being it's a harder styrene.

[Rick L]

What grit paper did you use for the mold lines? 

[vintagerpm]

4 hours ago, rmedtr6 said:

It appears to me that the solvents in the Zero Paints are too hot for the Tamiya primer and have reacted with it.  Best to use the same brand primer as paint whenever possible.

Interesting as I have used Tamiya primer under Zero Paints with no issues at all. I wonder if the primer layer was too thin or the Zero paints layed down too heavily. Or maybe the color coat was sprayed too soon after spraying the primer. If they really are "cracks" (they look like wrinkles to me in the photos), that can happen if you don't let the primer cure long enough.

[Plowboy]

Yep, you'll have to strip that and start over. Hope that the styrene didn't craze or you'll have a lot of sanding to do. And you'll probably have to sand the crazed areas with 400 grit. Then sand with 600 before primer. Chalk it up to a valuable lesson in what happens when you mix brands. Next time, use all Zero products or all Tamiya. I prefer Tamiya as I know it won't attack and craze styrene.

Edited December 19, 2022 by Plowboy

[StevenGuthmiller]

Seen this many times.

I would be very surprised if the plastic were not crazed.

 

Generally, when this happens, either the primer was applied too sparsely and the paint etched through all of the way to the plastic, or the paint was applied too heavily on the initial coat, which was more than the primer coat could create a barrier for.

My general rule of thumb whenever using lacquers is, more primer is always better than less, and light coats with the paint.

 

 

 

Steve

[Mike 1017]

3 hours ago, Plowboy said:

Yep, you'll have to strip that and start over. Hope that the styrene didn't craze or you'll have a lot of sanding to do. And you'll probably have to sand the crazed areas with 400 grit. Then sand with 600 before primer. Chalk it up to a valuable lesson in what happens when you mix brands. Next time, use all Zero products or all Tamiya. I prefer Tamiya as I know it won't attack and craze styrene.

I agree. I only use the same brand.

[Muncie]

4 hours ago, StevenGuthmiller said:

Seen this many times.

I would be very surprised if the plastic were not crazed.

 

Generally, when this happens, either the primer was applied too sparsely and the paint etched through all of the way to the plastic, or the paint was applied too heavily on the initial coat, which was more than the primer coat could create a barrier for.

My general rule of thumb whenever using lacquers is, more primer is always better than less, and light coats with the paint.

 

 

 

Steve

I agree with SWG.  He's one of the best around here for sure.  The thinners in the top coat got thru to the plastic.  You can see a mold line in the plastic on the fender thru the paint.  Another thing that may have happened is sanding the primer may have reduced the thickness of the primer and that made it easier for the top coat to do some damage.  The first coats of the final color should be sprayed very lightly and allowed to dry a little before heavier coats are applied.

[Dpate]

I had that effect a little when i used zero paints.  It was because i didn't wait long enough between coats.  Strip the body best you can, re-sand the body, wash, re prime 3 good coats not too heavy last coat needs to be wet (tamiya likes to go on wet), and repaint with light coats and 5-10 mins between coats.  Light coats with zero paint build it up until you achieve results you're after. Zero paints is a lot hotter than most automotive paints so take it slow. 4-5 light coats with least 10 mins between coats should build that maroon color up real nice.  You did nothing wrong with your process just got to wait longer between coats, and you don't really have to use the SAME brand for everything.  Automotive paints just need little more patience is all, and you'll have a great paint job - also all automotive paints aren't the same meaning some are hotter than others i.e zero paint hotter than say scalefinishes and gravity colors. 

Edited December 20, 2022 by Dpate

[FlyingDutchman]

Interesting theories everyone. One thing I can agree on with everyone is that this stuff is HOT. I got a drop of it straight from the airbrush cup splattered on a primed section of a piece and when I wiped away the spot, it had clearly removed all the primer. In this case it's a big blob of paint touching the primer, not a airbrush coat.

That said, I don't think the primer is to blame here. I'm seeing the same results on the underbody which was totally un-primed. And in general, the paint seems very smooth. It's almost TOO smooth where it's highlighting every microscratch. I haven't tried polishing yet but it seems a polish or clear coat might help.

What Dpate is saying could be true. I can't say I took a bunch of time between coats. I was spraying on very light coats but not waiting in between. This stuff is pre-thinned nicely. More to come!

 

[Plowboy]

Maybe try Tamiya TS-11 Maroon next time for your paint. Followed by three coats of Tamiya TS-13 clear. 

 

[Dpate]

17 minutes ago, FlyingDutchman said:

I can't say I took a bunch of time between coats. I was spraying on very light coats but not waiting in between.

There you go.  Like i said before i had this issue when i first used zero paints, but it didn't happen to the whole body just a small section.  After repainting and waiting 10 mins between coats it didn't happen again.  This is from there own instructions and tamiya primer is safe.

 

Edited December 20, 2022 by Dpate

[StevenGuthmiller]

3 hours ago, Dpate said:

you don't really have to use the SAME brand for everything.

I agree.

You don't have to use the same brand for everything, (I almost never do)  but you do need to know how what you're using is going to react with one and other.

Best to ask questions.

 

Now, I have heard of some incompatibility issues with Tamiya primer recently with some other paint brands, so you might want to consider that.

You might want to consider trying Duplicolor primer.

It might not be as simple to use as Tamiya, but you can rest assured that you can spray pretty much anything over it, and as long as there is enough of it to create a proper barrier, you're very unlikely to have any issues with it.

 

Duplicolor primer/sealer, Scale Finishes base, MCW color coats, and Duplicolor clear.

 

 

 

Steve

[FlyingDutchman]

2 hours ago, Dpate said:

There you go.  Like i said before i had this issue when i first used zero paints, but it didn't happen to the whole body just a small section.  After repainting and waiting 10 mins between coats it didn't happen again.  This is from there own instructions and tamiya primer is safe.

 

Yeah I honestly don't feel the primer is the issue here. Do you guys think it would be OK to wet sand the body and try repainting? I'm thinking another couple coats done lighter and more spaced out could be the way to go.

Edited December 20, 2022 by FlyingDutchman

[stitchdup]

52 minutes ago, FlyingDutchman said:

Yeah I honestly don't feel the primer is the issue here. Do you guys think it would be OK to wet sand the body and try repainting? I'm thinking another couple coats done lighter and more spaced out could be the way to go.

all thats going to do is make it worse. you'll need to reprime first and possibly have to use a filler primer due to the crazing. i've had this happen so i only use duplicolour primers and if its bare plastic i start with the clear plastic primer then go onto the normal primer. the plastic in kits just isn't as good as it used to be. testing on disposable plastic spoons is a good help too, the styrene in them tends to react more than models so if it works on the spoons you should be ok

[FlyingDutchman]

OK so here's an update. My night quickly turned into testing zero paints and other paints on spoons rather. But I'm OK chalking this model up to a loss for the sake of learning. With that in mind just to see what happened I applied Tamiya lacquer clear coat to the underside piece of the model. I applied a normal tack coat and then I did a couple heavy coats. I didn't do a particularly great job, and I wasn't careful about handling it or getting dust on it. Probably heavier than I would normally do on each coat but I was just looking to see if I could get some quick results. Bottom line is it made a huge improvement. You guys tell me what you think in the pictures but it seems the clear smooths out all those micro scratches. Originally this underside looked exactly the same as the regular body I posted picture of above. In same angles you might see what looks like orange peel.

I guess the question is don't people wet sand prior to clear coating? And doesn't wet sanding leave all kinds of swirl marks and micro scratches? So you'd think this would be similar? Do you all still think this is crazing?

I'm really starting to question my understanding of painting based on this!. Just for kicks I tested around with some other zero paints on spoons and I was able to replicate a similar result by applying heavy. But honestly it seems to happen slightly even when I apply the paint by using a bunch of super thin coats.

 

Edited December 20, 2022 by FlyingDutchman

[Plowboy]

On a chassis like you just did, I won't sand before clear unless there's a flaw that needs it. On a body, I always sand the paint before clear with at least 1000 grit to get the paint as smooth as possible. When you shoot the clear, all of the sanding scratches will disappear. I normally shoot two coats of clear, sand with 2000 grit and shoot one more. Then sand and polish. If you don't plan to polish the paint, just shoot one good wet coat.

[jaymcminn]

One thing the clear gloss is pointing out on your chassis is coverage issues that probably stem from applying multiple coats of paint too quickly (the same thing that likely caused the crazing). When too much paint goes on too wet it will lift lower layers including primer. It will redistribute the paint away from raised areas and sharp edges, including around panel lines. It'll even reveal things like sanding scratches in the bodywork under the primer. By giving each coat time to flash, you'll be building those crucial layers of paint in a way that creates a smooth surface with even coverage. 

Something else to consider is how that Tamiya clear will look after it's completely cured. TS13 is wonderful stuff but it actually takes a while to completely cure, and it shrinks while it cures. Once it's done, it might show more of the initial damage in the paintwork.

You already have the answer to the question of trying to salvage the paint. If you're getting back into the hobby, learning how to strip paint and start over (and when to strip paint and start over) is pretty important. Trying to salvage a paint job with this level of damage just isn't practical. Using more paint to cover flaws in your current coats will just wind up exacerbating the current issues. 

You seem pretty comfortable working with an airbrush, but Plowboy's suggestion above of Tamiya rattlecan paints is a good one. These paints are absolutely wonderful to work with, and the TS11 maroon was actually created as a factory color for the 1/12 Datsun 240zg when the TS paints were initially released. They even decant nicely for airbrushing. 

Finally, welcome to the frustrating and wonderful world of automotive modeling. There's a mountain of learning ahead of you, but this site is full of Sherpas that will help you climb it!

 

 

[Matt Bacon]

You're laying the Zero paint on too thick. It works fine on Tamiya primer. Just apply light coats 5-10 minutes apart until the colour looks even and doesn't change noticeably from one coat to the next. It will only ever look matt --  if you can see a wet coat, it's too thick and will etch and wrinkle. The depth of colour and shinyness with Zero comes with the gloss coat over the top.

best regards,

Matt

[peteski]

19 hours ago, FlyingDutchman said:

Interesting theories everyone. One thing I can agree on with everyone is that this stuff is HOT. I got a drop of it straight from the airbrush cup splattered on a primed section of a piece and when I wiped away the spot, it had clearly removed all the primer. In this case it's a big blob of paint touching the primer, not a airbrush coat.

That said, I don't think the primer is to blame here. I'm seeing the same results on the underbody which was totally un-primed. And in general, the paint seems very smooth. It's almost TOO smooth where it's highlighting every microscratch. I haven't tried polishing yet but it seems a polish or clear coat might help.

What Dpate is saying could be true. I can't say I took a bunch of time between coats. I was spraying on very light coats but not waiting in between. This stuff is pre-thinned nicely. More to come!

 

Joe,  if the paint you are spraying is "hot" enough to penetrate the primer and craze the plastic surface, then of course same thing will happen when you apply it to bare plastic.  Spraying multiple  lighter coats (where the hot solvent evaporates quicker) will minimize the crazing, but will also not give you very smooth finish.

Back in the distant past we used hobby paints on plastic model kits. Those paints (usually enamels) were made using solvents which were mild enough not to attack plastic. But as the hobby marched forward modelers started messing around with automotive touch-up paints which were designed for metal surfaces and used solvents hotter than hobby paints. With those you needed to apply a primer which had mild solvents that did not attack plastic, The primer acts as a barrier, preventing the solvents in the "hot" automotive paints from damaging the plastic body.  Companies such as Splash Paints sell basically small quantities of automotive paints to modelers.  From what i see on the forums, there is no definitive safe combinations of the model's polystyrene blend, primer, and "hot" paint which is guaranteed not to ruin your paint job.  What seems to work for some modelers, does not work for others.  The painting technique (how thin the paint is, and how heavy of a coat is applied) is also part of the safe painting equation.

There is a lot involved in painting success. If we could only go back to the old days where we used Testors or Pactra paints for our models and didn't have to worry about paint/model compatibility.

[Plowboy]

49 minutes ago, peteski said:

There is a lot involved in painting success. If we could only go back to the old days where we used Testors or Pactra paints for our models and didn't have to worry about paint/model compatibility.

No need to go back to that stuff. We have Tamiya that can be sprayed over bare styrene. 

[Dave G.]

There still is Testors enamels thus far. Both MCW and Scale Finishes offer enamels. And I do quite well decanting other enamel spray cans, thin a bit more and airbrush. We aren't locked into hot lacquers. Even craft paints once you learn the ropes of spraying them work quite well for base color coating then clear with a mild clear coat.. Many options besides hot lacquers. The thing about acrylics is they make a good barrier to lacquer clear coats.

But if you're gonna use Zero and other hot lacquer you need to find that zone where the paint is wet but in a mist coat. This takes a pressure balance between air and paint flow, that the thin mist goes on pretty wet and doesn't get gravelly. Distance from the subject and speed of the passes enter into this. And you still might get a bit of sand scratch swelling here or there. The good news about that is once dry you can lightly scuff and shoot another coat. Hot lacquer is not my cup of tea but I do use it here and there. Everybody pretty much seems to be base coat clear coating with these lacquers so the color coat drying matt is basically of no concern. To me that being the case then I can base coat in acrylic, no danger of burn through, still use whatever clear. If you clear right, not going for the infamous wet look but a realistic impression you can get to a good classics era car look and nobody knows if it acrylic or lacquer under the clear. The same end can be said for enamel shot straight up as color only ( no clear) and get a nice OEM or even restoration or museum finish ( non of which by the way are the same). If you want to get there with hot lacquer and no clear which also would be accurate you will rub your brains out. Hot lacquer to me except maybe for radiators or certainly metalizers boil down to a big PITA. Just my honest opinion. Now if they had not moved to hot acrylic lacquer and kept it nitro lacquer I'd be on board because those you can almost spit polish the color coat, so much easier to work with.