Tack / mist coat vs wet coat

[atomicholiday]

This is something I’ve always been a little confused about.  You hear the these terms thrown around a lot when talking about painting.

I Think it’s pretty clear what “wet” coats are, but not as much when talking about tack coats and mist coats.  

While I do understand their purpose, and that they are very thin, I’m not really sure how they should actually look when laying them down.  Should a mist coat actually look dull and dry?  Or should it appear wet, but just thinner than a true wet coat?

I’ve been laying them down very thin and almost dry (still tacky though) but I’m wondering if that doesn’t cause more orange peel.  Should they be wetter looking when they go on?

i hope I’m being clear here.  I have a feeling this will be a very subjective concept.  Also, this can apply to either rattle cans or airbrush.

[Ace-Garageguy]

A lot of terms get thrown around by people who don't really know what they're talking about, have never produced an outstanding finish on anything, but present themselves as "experts"...and that's the internet in general.

"Tack coat" really only applies to enamels that flow out considerably after application. The "tack coat" helps avoid running of a subsequent heavier, wetter, coat because the solvents in the next coat soak into the tacky one, raising the viscosity of the paint almost instantly.

"Mist coats" are more about lacquer (or other paint products that "flash" rapidly), and most painters have their own individual understanding of the concept even if they've never really thought it through in words.

It's difficult to do an actual "mist coat" with rattlecans, as it requires an ability to control material delivery with the gun or airbrush. Most rattlecan "mist coats" are in reality dry-spray applied from too far away, or with excessively fast passes, and result in a grainy surface that just tends to contribute to orange-peel.

A final thought...when taking advice from anyone, try to find examples of the work they turn out so you can judge the validity of what they tell you.

Steven Guthmiller, for instance, is one modeler whose paint advice you can rely on. His models consistently prove it.

 

Edited July 24, 2024 by Ace-Garageguy
TYPO

[atomicholiday]

Thanks for your input Bill.  That makes sense, and confirms some of my suspicions.  Especially regarding mist coats.?

[Matt Bacon]

I can’t remember where I saw it online, but the technique I use for Tamiya rattle cans was invented by a pro modeller. It uses “splatter coats”. You don’t make any attempt to get even coverage coats, light or wet. You just do pass after pass, lightly, and build up to an even dense coverage by overlaying many light speckled coats. It doesn’t give orange peel because the paint goes on wet from reasonably close but moving fast. You can apply the coats 5-10 minutes apart because there’s not much thickness of paint and the solvent goes pretty rapidly. And because it’s painted in one session, you don’t get the issues of cracking due to differential shrinkage that can occur if you do solid coats of Tamiya rattle can paint spread out over a 24-48 hours to allow the first layer to “dry” before applying the next. (Actually, in my experience Tamiya acrylic takes several days to fully cure and shrink as far as it’s going to, which is why I wait a week or so before using Novus on it. Any surface texture you can see 12 hours after painting has usually tightened up and disappeared into a glossy surface after a few days.) Painting wet coats from a Tamiya can risks not just runs, but the pigment, especially metallic flake becoming unevenly distributed…

best,

M.

[bobss396]

I'm not big on "mist" coats, this is a good way to get a grainy mess. On bodies, after priming I start painting with the body upside down. This way I get the rockers and other hard-to-reach places with good initial coverage. Once that is dry, I'll color-sand out anything that is not dead nuts smooth.

Then I'll turn the body right side up and start painting. In almost all cases, I'll color-sand between coats. My last coat(s) get applied on the heavy-ish side. Worst case, I'll get a minor sag once in a while, an easy fix with lacquers.

[StevenGuthmiller]

Mist coats with lacquer is a fairly dangerous prospect.

It's very easy to get a grainy texture.

But, even that is not an insurmountable issue.

You would be amazed at what you can overcome with a small attitude adjustment.

 

Personally, I don't get into the fancy paint terms too much.

I'm old school from a German/Norwegian area of the country.

For me, there's only "Tin" and "Tick".

 

I appreciate Bill's recommendation, but please know that I am no professional painter.

I've struggled with laying down a perfect paint job for most of my modeling career, and still do to some extent.

That all changed when I realized that it was a fool's errand, (at least for me) to expect to be able to get a perfect dust, blemish, and orange peel free finish, and I began to look at paint from a different perspective.

It occurred to me that I was putting way too much unnecessary pressure on myself, and soon found that cutting and polishing the finish was the answer.

It of course requires additional elbow grease, but I can tell you this.

Since adopting this attitude, I haven't had to strip a paint job due to paint issues in probably more than 20 years!

I've only stripped a few due to dissatisfaction with color.

It removes a great deal of pressure and has had a huge freeing affect on my attitude towards painting models.

I pretty much know going in, (barring any unforeseen major incident) that my paint job is going to turn out.

 

Of course, the products that you are using are also very key to what can be expected, as well as the commitment of the modeler.

If you go in thinking that your going to get that perfect paint job with one heavy coat of enamel over bare plastic, well more power to you if you're lucky enough to end up with anything remotely presentable.

 

Just for an illustration, here is an example of what most would have considered a failed paint job by conventional thought.

This model was painted some years ago, (air brushed with MCW lacquer) and the color was applied too dry, giving the surface a somewhat grainy texture.

I could have thrown in the towel and stripped it, or did what I did and shot a few coats of clear over it, and cut and polished the model.

 

I think I made the correct choice.

 

 

 

 

 

 

Steve

 

Edited July 25, 2024 by StevenGuthmiller

[Skip]

Don't let Steve fool you, however he does it his paintwork always looks great. I have been modeling and painting since I was 8 or 9 years old, I've got the gray whiskers to prove that I've been at it a while, but my paint never looks as good as Steve's does, I'm impressed with the way he does things!

I for one would like to see Steve do an article in said magazine with a rough detail sketch of how he does his paint from first scuff of the body, bodywork primer, color coats and clearcoat. I know he has sort of detailed his painting method on here a few times but to have something in print would be really nice to refer back to.

[Nicholas]

tack mist coat to me came from people using rattle cans,i never subscribed to that theory with my airbrush painting, although i only paint with enamel,if i was going to use lacquer i would do a couple of mist coats and go slow/steady with the coats until i am  satisfied with the paint job as in the past i applied too much too soon and got into problems with lacquer paint job. ,as far as enamel goes i only apply a initial base coat first then blast the paint on in multiple coats until im satisfied with the results(being careful to not lose body detail).

[bobss396]

I went to lacquers only 20+ years ago and have never turned back. They are more forgiving that enamels and the learning curve is short as well.

I am this many years old hearing the term "tack coat" for the first time.

Edited July 26, 2024 by bobss396

[Skip]

5 hours ago, bobss396 said:

I went to lacquers only 20+ years ago and have never turned back. They are more forgiving that enamels and the learning curve is short as well.

I am this many years old hearing the term "tack coat" for the first time.

True, Tacking was a term used by painters primarily shooting enamel paints, it would be a misty coat 60 - 80% coverage which was allowed to flash off then the heavier color coats applied. If you go back and read some of the Model Car Science, Car Model articles where they were shooting Enamel Paints, they did call for the "Tack Coat" or "Mist Coat" which was not full coverage at all, it just gave the subsequent coats something to both mechanically and chemically bond to. 

I have worked with Painters on bridge projects and such who were applying Epoxy-Paints, they referred to the first of a three-coat system - as the "Tack Coat" - second "Mid-Coat" - third "Color Coat" all three coats the being same color. Referring to the first Primer Coat as a "Tack Coat" - second the "Primer Coat". So, it's probably an older painter's term that with both the passing of time and improved materials isn't being used as widely as it used to be. Not to mention with newer spray methods, HVLP and others the term just isn't used as much.

Enamels by themselves tend to run long after the brushes, spray can, or spray gear gets cleaned and put away. Which is why the old Sign Painters and Pin Stripers cut their enamels with Lacquer thinner. Recently, Don Yost was another proponent who got it! If you're going to paint with Enamels cut them with Lacquer Thinner, they flash off quicker, less prone to the running after you walk away, lay down smoother, just makes them easier to shoot. I mostly use Lacquers as well, but if there is a color that I'm going to use that's an enamel, it always gets cut with whatever lacquer thinner/reducer that I have close at hand.

A reminder on Safety: Enamels are probably a "safer" paint to use than Lacquers, Acrylic Lacquers or Urethane based paints, you'd have to huff a lot of enamel paint to get a buzz if that were at all possible. LoL!  (Don't know, never purposely huffed anything! I've got plenty buzzed a few times spraying lacquers without the right mask! That's another story.) Mitigate the health risks with whatever PPE the paint manufacturer recommends, even for the small stuff I'm wearing the proper mask and Nitril gloves! Acrylic's being probably the absolute safest hobby paints out there, you can protect yourself from the finely ground pigments with a dust mask or better yet and N-95 mask. These days, in my "Old Fart years" (like a whole lot of us are), I'm worrying more about what I am ingesting through fumes, skin exposure and or other exposures than I used to be when I was say in my teens and twenties... 

Interestingly enough, I read an article on painter safety in the now belly up - Bob Bond's "Auto Art Magazine". The gist of the article was they were talking about how many of the painters from the 1950's and earlier consumed so much alcohol after working with paints. (Not to promote its consumption in large quantities as lots of them did.)  Alcohol was found to flush many of the toxins picked up during the painting process. Primarily targeted to the liver, only to replace them with the "toxins" from the alcohol. The end of the story talked about how many of the old painters probably had no idea they were "cleansing", they were just relaxing and knocking back a few cold ones after a hard day on the job!