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I was wondering whether it was strictly necessary to undercoat?

My understanding is that miniature paints are significantly different to the acrylic paints that you can get at the paint shop (in particular, they adhere to enamel paints whereas apparently this can't usually be done with house paints). I had also heard of people "undercoating" with a GW Abbadon Black acrylic paint, raising the issue of how this differs to putting down a coat of whatever paint you were planning to paint the model with.

You don't strictly need to, but it is a good practice - a good primer will grip the plastic better, as well as hold onto the paint. This will stop scratches a lot more.

That said, it's been anecdotally proven time and time again here where people realise that they haven't been priming, and haven't noticed any problems.

I prime, because that is the accepted logic. It also makes sense to me. I have not done any further research or testing.

Sounds like you might be confusing undercoating with priming.


An undercoat is a solid base color that is used to create a standard 'base' layer for your paint, so that colours come out smooth and even.

A primer is a specific type of paint that bonds to the surface being painted, and often provides a 'key' (or slightly textured surface) to help the paint stick.



So to answer either question - yes, an undercoat is a good idea. A primer can be a good idea if you're expecting your miniatures to get a bit of rough treatment, particularly on metal models, but isn't strictly necessary... most acrylic model paints bond quite well to just about any surface anyway.

I've been painting gaming minis for more than 20 years now, with the vast majority of them basecoated with regular spray paint or GW Chaos Black straight out of the pot, rather than primed, with very little sign of wear and tear even on the armies that have had the most use.





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kb_lock wrote:

That said, it's been anecdotally proven time and time again here where people realise that they haven't been priming, and haven't noticed any problems..

Yeah, there's an awful lot of people out there who think that they're priming, when they're just using a regular spraypaint rather than a primer...

Not sure if they've changed, as I don't buy them... but GW's black and white sprays were marketed as primers for years despite not actually being primers at all.

I think that the GW primers are actually primers now, but I'm not spending $30 on a can of spray paint to find out (lol, I wrote $30 as a joke "over the top" price - it's actually $29)

There also some Vallejo colour that is called "primer red" or something, but it isn't a primer, it is just a descriptive name.

That said, is Vallejo primer actually primer anyway


Automatically Appended Next Post:

Corax White does not say anything about being a primer

https://www.games-workshop.com/en-AU/Corax-White-Spray-Global

Corax White Spray is designed for basecoating plastic, resin and metal Citadel miniatures. Reformulated for maximum results, with a fantastic off-white colour, it's a fast way to get a uniform base of colour onto models.

This is an ideal spray for basecoating any miniature in white, quickly and with minimal fuss.

Whether something is called a primer or not doesn't really matter, as long as it serves the purpose of a primer.

I should write a screed about primers and save it somewhere so I can copy/paste it when this topic comes up

The word "primer" can mean a lot of different things. It is simply preparing the surface for your next layer of paint. The terms "undercoat" and "primer" can be used interchangeably.

In the context of plastic wargaming models, the purpose of a primer is mainly to make further layers of paint stick well to the model and provide a consistent colour to paint over.

If a paint can achieve those things well, then it really doesn't matter if it's called a primer or not. There always used to be argument whether GW Skull White spray paint was a "primer" or not.... it doesn't really matter because it successfully achieved those 2 things so it was a primer in function if not in name.

Really any matte paint that has good adhesion and is resilient can serve as a primer. Spray paints are often (not always) more resilient than brush on paints so often can be used as primers even if they're not called primers.



As to whether it's necessary or not? Well that's entirely up to you. I do it as a matter of course for any model that I intend to play a game with because more than anything I don't want paint rubbing off my miniatures when playing with them, anything that can help with that is important to me.

There is an argument for NOT priming in that by adding an additional layer of paint, it can soften details. There are people who paint extremely good display quality models that don't prime them. So it's definitely not a requirement to painting a good model.

I'm mostly with Skink on this one.

I've 'primed' more than a few plastic models with flat/matte enamel spray paint. They've held up just fine. I 'primed' them, but I didn't use a primer to do so. Nowadays, I generally use an actual primer. PRIMER PRIMER PRIMER! Heard the word enough? I've been in a dozen conversations, over the years, revolving purely around the terminology of the issue - the chemistry or necessity conversations would easily quintuple that.

Regardless of the chemical formulation and the specific label it bears, if it sticks to the model and the next coat of paint sticks to it... well, it's done its job (granted, some do a better job of resisting damage). I'd always recommend something of that nature, since I've found that paints respond better over some sort of base (whether an aerosol enamel spray paint, aerosol primer, or brushed/airbrushed PU primer), but that's just me speaking from experience that happens to align with that of many others.

Yes in 99% of cases.

 oadie wrote:
I've 'primed' more than a few plastic models with flat/matte enamel spray paint.

Did you find acrylic paint spreads well enough over an enamel base? I've been meaning to try an enamel primer under an acrylic but haven't gotten around to it yet. Not a scientific test at all, but I've noticed when I paint a model with a combination of enamels and acrylics, when I go to apply a wash it will tend to bead up on the enamel areas even though the enamel was matte.

I do sometimes use enamel primer for enamel paints, though enamels aren't as finicky about sticking to plastic as acrylics are so sometimes I don't bother priming at all when using enamels.

The vast majority of sprays are enamels... Acrylic sprays are mostly only found in specialty craft stores.

Acrylic model paints stick to them (and most other things) just fine, although yes, washes straight over the spray can bead up a bit.

 insaniak wrote:
The vast majority of sprays are enamels... Acrylic sprays are mostly only found in specialty craft stores.

A lot of places sell acrylic sprays (or lacquer acrylics), I don't know which one would be in the majority but it's definitely not just craft stores that sell acrylic. I was under the impression GW sprays were acrylic or lacquer acrylic but to be honest I've never checked.

There's also water based enamel, which may work better than oil based enamel, I haven't tried them though.

I tend to stick to acrylics when I'm buying non-hobby sprays. Automotive stores carry a large range of both acrylic and enamel sprays.

I remember as a kid, back when you could buy spray paints from regular stores like Coles and Woolworths, they had a range of really cheap enamel sprays and I tried a few of them (we're talking about 20 years ago here ) and they were terrible. Stuck to the model beautifully, but hobby acrylic paint wouldn't stick to them.

But I haven't gone back to try enamel sprays again.

If I just airbrush a regular Testors enamel on to a model, acrylic paint won't stick brilliantly to it either unless I give it a coat of non-enamel varnish over the enamel. But Humbrol make a specific enamel primer and I don't know if that behaves differently, it's on my "things to try" list.

I have a bit of a dumb question. Does it really matter the color I am priming it - black, white etc.

Depends what your end goal for colour is. The primer will set the tone for how dark it is in the end.

Yes, the colour of your basecoat will affect how bright the end result is. While your specific painting style makes a difference as well, in general white is better for brighter colours, black is better for a darker tone, or for metallics.

Some people prefer grey as a middle ground, or just basecoating in the primary colour of their scheme as a timesaver.

There are basically two issues with priming and basecoating.

First, durability - most primers aren't acrylic paints, and most primers stick onto plastic a lot better than acrylic paints. Just use an army painter primer on a model, and try to get it all off a year later. Good luck with that. As other peeps have said, this makes them a little more scratch resistant, both during the paint process and for gaming.

Second, I'm assuming that you would be using a paintbrush (not an airbrush) to put on that first coat of abbadon black, or whatever color. The problem with this is that, even on a color like black, is that it's impossible to get a brushed on coat as even as a sprayed on coat. That means that you start at a disadvantage in terms of getting a model with minimal visible brushstrokes, because you start off with an uneven first layer of paint. This is compounded if you are painting something that is, for example, orange, red, yellow, green, or white -- your first layer against grey plastic will look cruddy. It will take a second layer, then a third, and a fourth... by the time you have that first base coat, it will have taken you many coats of paint to get, for example, white for white scars, and unless you're spending way more time than you should, it will probably be lumpy.

As insaniak put it, you're better off just spraying the color you want on there.

Personally, like undercoating (priming) to a color close to what most of my basecoat will be, and then spraying on a basecoat if there is a dominant color, even if that means using a rattle can.

 Talys wrote:


As insaniak put it, you're better off just spraying the color you want on there.

That's not actually what insaniak said...

For those of us that just want to get models to tabletop standard, Priming models black (and specifically black) has a sort of hidden bonus. Any of those cracks that are deep and hard to get to can be overlooked during painting if you prime it back, as most people will automatically assume it to be shadow. Now the more meticulous painters would paint pieces separately specifically to avoid this situation, but if you are painting in batches and want a little cheat, a little black spray into an armpit or cloak crack will do wonders in time saving, especially if it happens to match your mini's actual primary color (like me and my black legion).

 MechaEmperor7000 wrote:
For those of us that just want to get models to tabletop standard, Priming models black (and specifically black) has a sort of hidden bonus

If you're trying to get models on the table quickly, priming white can potentially have an advantage as well.

If you prime white you can work from highlights down to shades rather than working from shades up to highlights. Using thinned down paints and washes, the white undercoat will produce some shading as the paint naturally pools in the crevices. I use this technique for most my speed painted models, white primer and then mix up my basecoat to be quite thin, probably about half way between a layer and wash.

They may not look awesome, but that's how I did all these guys, and most of them were done in under half an hour per dude (compared to 2+ hours for my regular techniques). The Spider Riders probably took me about an hour each, but that's because they're more complicated models and I spent a bit more time on them for a competition, but still massively faster than working my way from a black primer.

The issues of undercoating and priming seemed to have been well covered above, but as for this...

hasdrubalsbrother wrote:

My understanding is that miniature paints are significantly different to the acrylic paints that you can get at the paint shop (in particular, they adhere to enamel paints whereas apparently this can't usually be done with house paints).

It's not quite true. Miniature paints and housepaints are extremely similar. They have different quantities of pigment and the pigment may be finer or less fine, and they may also have different visocities, but you're essentially dealing with variants on a theme of pigments suspended in latex acrylic.

Now, I wouldn't recommend house paint for minis, as it's just too thick. (but it's great for terrain) but they will both mostly adhere to the same surfaces. The quality the surface is far more important than whether it is enamel (I assume you mean oil based) or acrylic. I routinely use oil-based spray paints as my basecoat and priming layer on minis. It dries fast, is actually more durable than acrylic and the VOC's in it mean that it usually bonds even stronger to plastics. Acrylic paints (I use craft paints and miniature paints) will adhere just fine to these oil-based enamels it as long as it is a matte finish with some "tooth". Tooth is the ability of a surface for paint to adhere to it.

Gloss (sometimes incorrectly referred to generically as enamels) paints will be harder to paint on whether oil or acrylic because they tend to have much less tooth.

 Eilif wrote:
Acrylic paints (I use craft paints and miniature paints) will adhere just fine to these oil-based enamels it as long as it is a matte finish with some "tooth".

I'm not sure you can say that in general, as I know my hobby acrylics bead up on airbrushed Testors enamel, even though it's a matte enamel and I've tried at least 1 matte enamel spray that acrylic paint just did not want to paint over.

Even though I have some background in materials engineering, I'm not a chemist and have never studied paints, so I'm trying to get my head around the terminology, but according to wikipedia....

There is no generally accepted definition or standard for use of the term enamel paint, and not all enamel-type paints may use it.

Typically the term "enamel paint" is used to describe oil-based covering products, usually with a significant amount of gloss in them, however recently many latex or water-based paints have adopted the term as well. The term today means "hard surfaced paint" and usually is in reference to paint brands of higher quality, floor coatings of a high gloss finish, or spray paints. Most enamel paints are alkyd resin based. Some enamel paints have been made by adding varnish to oil-based paint.

So it seems to me that making general statements about "enamels" isn't really possible when the term is being used for a wide range of substances. Even "acrylic" is referring to a family of chemicals, not one specific chemical. Lacquer based acrylics can behave quite differently to water based ones.

Miniature paint, as far as I know, simply has finer pigments (the particles suspended in the liquid acrylic medium that gives it color) than more "general use" acrylic paints. However high-grade artist acrylics also have this, so they can be used for miniature painting too (part of the reason I do warhammer is because I'm also a painter on the side so paints are never an issue with me).

Just, for the love of god, do NOT use dollar store paints unless you've tested them yourself. I've had ones that get chunky on a single coat, even when it's watered down to cheap coolaid levels.

AllSeeingSkink wrote:

 Eilif wrote:
Acrylic paints (I use craft paints and miniature paints) will adhere just fine to these oil-based enamels it as long as it is a matte finish with some "tooth".

I'm not sure you can say that in general, as I know my hobby acrylics bead up on airbrushed Testors enamel, even though it's a matte enamel and I've tried at least 1 matte enamel spray that acrylic paint just did not want to paint over.

Have you tried a flow-aid? You can use one purpose made or some folks will add a bit of dish soap or windex. Folks use them to make washes but it can help with the surface tension of your paint.

Sounds like what you've got is a surface that while matte is probably so smooth that the paint has nothing to grab so the paint beads up like water on a windshield. A flow aid will lessen the surface tension of your paint and should make it stop beading up.

MechaEmperor7000 wrote:
Just, for the love of god, do NOT use dollar store paints unless you've tested them yourself. I've had ones that get chunky on a single coat, even when it's watered down to cheap coolaid levels.

I use cheap craft paint, but I do agree that you should test them or go with a known brand. Craft paints come in a wide variety of qualities. I highly recommend the "Delta Ceramcoat" brand it costs about 30 cents more ($1.20 vs $0.89) than the cheapest stuff for a 2 oz bottle, but it's got pigmentation and flow that are very close to the quality found in hobby paints.

If you use craft paints it's also not a bad idea to have some flow aid or matte medium around to thin and smooth your paints if necessary. I've not found it necessary with Delta, but some others do benefit from it.

I find that a good spray of whatever you use as a "primer" makes the paint adhere to the model better. Just painting straight onto the plastic requires another layer or two when base coating.