Primer for enamels?

[zuludog]

I've been brush painting with enamels for years and I hardly ever use a primer. The exceptions are where there are -

different colours of plastic, such as the original Matchbox kits or when you've done a conversion using parts from different kits
contrasts between the plastic and the final colour, such as dark green over white plastic or pale blue over black plastic
large areas of patching & filling

In those cases I use a primer, but I don't use a proper primer, just whatever kind of pale- to - medium matt grey is convenient
This evens out colours and textures, and shows any uneven-ness, scratches, and so on
I often give the primer coat a very light sanding

If I don't use a primer the first colour usually needs two coats to cover properly, so you could say that it acts as its own primer .... or is that an undercoat?

Red, yellow, and pale blue paints are translucent, so you should paint those over a base coat of white anyway

I've found out all this from my existing enamel paints; various makes, but all quite old, and quite dense and cover well
But I've heard that modern enamels have been reformulated and are not as good, so perhaps you should use a primer more often - can anyone else comment?

[JR]

Hi Zuludog
I would say thai is an undercoat when you use a second coat .
Paint provides the colour hiding, sheen, scrub resistance and protection against the elements. Primers seal the substrate, help provide uniform coverage, provide adhesion (between the substrate or wall and the paint) and block stains. In other words, a primer prepares the wall you are about to paint.
This applies to walls etc but it's the same principal with any painting
Take a canvas, you would use a heavy coat of artists gesso.
It appears some people don't and happily carry on, others like me always use a primer, most likely because I spent many years in the building and joinery trade .
At the end of the day each to their own .

[BattleshipBob]

Thank you all for the sound advice, primer it is lol

Bob

[Guest]

Why do some people not use [primer] I'll never know.

If the paint adheres well enough by itself, I don’t see a need for primer. All enamels I’ve ever used don’t need it on plastic, and neither do Tamiya and Mr. Hobby acrylics — you need to put in a fair amount of effort for any of these to rub off. Water-based acrylics typically adhere less well, and most model paint applied to resin or metal benefits from a primer too, though.

I’ve got hundreds of hard plastic wargames figures painted primarily with Tamiya acrylics, none of which I primed and all of which still have a perfectly fine coat of paint on them despite having been chucked together into a box for transport lots of times. Do that with metal figures, though, even with primer, and you’ll soon have bare spots showing through.

[Tim Marlow]

I’ve got hundreds of hard plastic wargames figures painted primarily with Tamiya acrylics, none of which I primed and all of which still have a perfectly fine coat of paint on them despite having been chucked together into a box for transport lots of times. Do that with metal figures, though, even with primer, and you’ll soon have bare spots showing through.

Nothing to do with the paint though is it Jakko. That’s due to the comparative weights of the figures. If you carry metal figures loose in a box the energy produced by the impacts would remove any paint you care to name.

[Bugatti Fan]

Each to their own on this subject. However, paint always needs a 'key'.
My personal method is to go over the model parts with either Scotchbrite wadding or fine wet'n'dry paper to prepare the model surface itself to a dull matt finish.
Wash off with dilution of detergent to get rid of any dust and mould release agent. When dry I always prime with automotive acrylic primer, before top coating.
Never use acrylic over enamels or lacquers. Oil based paints take a long time to thoroughly dry and an acrylic used on top will be like putting a plastic membrane over it that will eventually bubble through.
It is OK the other way around though using enamels over acrylics as acrylics dry fast.

[Guest]

It’s also due to adhering better to the plastic than to metal, I think. My experience is that it wears off much more easily from metal figures just by gaming with them, than from plastic figures that see the same or even more use.

[rtfoe]

That’s what I was reminiscing about too :smiling3: Humbrol straight from the tin to the model.

Likewise in my youth and when Humbrol was the only paint I used till the acrylics came into my life and then I started priming having seen it done in magazines. Now I prime to check flaws and even out the surface color of plastic and fillers.

Cheers,
Richard

[Tim Marlow]

It’s also due to adhering better to the plastic than to metal, I think. My experience is that it wears off much more easily from metal figures just by gaming with them, than from plastic figures that see the same or even more use.

I must admit I’ve never had that issue Jakko. I have metals that are forty years old, with broken bayonets and cracked swords from extensive use, but they still look as bad as the day that I painted them
I think washing before priming is essential on anything that is likely to get a lot of handling, like gaming figures. It just gives the primer the best chance to do it’s job properly.
Do you varnish your figures? I know a lot of gamers don’t because it is another stage to go through before the figures can be gamed with. I have always gloss varnished then matt varnished mine. Gloss varnish has a much lower friction coefficient so will wear much less than matt. If the Matt starts wearing off you get a chance to re varnish before the main paint job is damaged. Saying that, I have never actually had to re varnish anything :tongue-out3:. I still keep it as a finishing stage though because it makes the matt final coat much more reliable.

[Guest]

For metal figures, I’ve always started by taking off the layer of white crap that’s usually all over them, with a copper-wire brush (“Oh no! It’ll scratch the figures!” lead ones maybe, pewter ones will be fine), then priming, followed by painting, and after that a layer of gloss varnish and then matt. Not that the figures chipped much after all that, but more than the plastic ones. Metal figures of other people tended to chip more, probably because they were less thorough

[Tim Marlow]

I used to suede brush my old minifigs etc back in the day as well. After all, there wasn’t much detail to lose…..Now that lead has been eliminated from the mix I no longer find this necessary. Never had a lead rot issue either, but then, I don’t close up unpainted figures in air tight containers…..
They still get a scrub with an old toothbrush and dish soap before priming though :tongue-out3:

[Guest]

I do it mainly so that glue will stick better. I’ve seen too many metal figures (the vast majority of them not mine) on which parts broke off because superglue had securely bonded two layers of crap together, which were not stuck to the metal as well as to the glue …

[Tim Marlow]

I Always use two part epoxy on metals. The bond is so superior it’s not even funny….superglue has no shear strength at all in my experience so joints fail under any stress whatever. I have even drilled small blind holes to improve glue bonding on critical joints. Never bothered drilling and pinning, though I always replace lances and spears with brass or nickel silver pin wire whenever possible.

[Guest]

Same, except for small parts where mixing up epoxy is too much bother But even then I clean off the layer of residue before glueing.

[Mini Me]

What is primer to a modeler who uses nothing but enamel or lacquer paint on plastic. In the past 40 years I have used nothing but enamels and lacquers on styrene and found them to be superior when it comes to adhesion. When thinned properly for spraying there is enough solvents in the sprayed material to etch its way into the styrene to more than lock itself onto the base material. The only use I have had for a primer, is to create a uniform base coat when required so there is topcoat uniformity in the end result. I do, but not often seal with a matte coat if I think it is beneficial to the overall appearance of the finished model, otherwise it is left as is.