Does *everything* needs to be primed?

[godzilla]

Hey guys, so just a little question. Do you / should you prime everything that you paint?

 

I've obviously primed large body parts etc, but right now I am working on some engine detail and have been painting straight on to the little plastic parts with a brush. In general it comes up ok, though I should thin the paint a little I guess as it tends to thicken quickly and easily goes streaky.

Edited June 29, 2018 by godzilla

[Graham Boak]

I don't.  A little answer for what I suspect should be a bigger question.  What materials are you painting?  Which paints are you using?  I paint with enamels onto polystyrene and resin, and some white metal.

[Black Knight]

Usually I never do prime; as Graham I paint [mostly] with enamels, straight onto plastic, resin or white-metal. I do occasionally undercoat if I've used an amount of fillers which need toned down. For some acrylics I would use an enamel as an undercoat, but with some I don't bother, they have good enough coverage and adherence

[Corsairfoxfouruncle]

With rare exceptions (seams) on bare metal paint jobs i almost never prime.

Edited June 29, 2018 by Corsairfoxfouruncle

[Mike]

I prime everything (except the glazing )  - it gives a nice uniform finish, and the paint sticks better when airbrushed IMHO.

[VMA131Marine]

2 hours ago, godzilla said:

Hey guys, so just a little question. Do you / should you prime everything that you paint?

I've been using Vallejo Polyurethane Acrylic Flat black primer on all my latest builds. The primer coat helps you detect any pinholes and unfilled seams so you can fix them before you paint your colour coats. In addition, using black works great for doing pre-shading on aircraft and armour.

[John Laidlaw]

It depends on what type of paint, and which method of application. Enamel applied by brush really doesn't need it. Tamiya acrylic applied by airbrush really doesn't need it (although it's best to clear coat it ASAP to prevent it being rubbed off when handling). Some other acrylics applied by brush are fairly tough - Revell Aqua Color and Lifecolor come to mind - whereas others, such as Vallejo Model Color and Model Air can be a bit fragile without a primer to grip.

[TimB]

I prime most surfaces with Gunze 1200 thinned down with their leveling thinner.  I find it helps most acrylics adhere better, and helps me spot the frequent stupid mistakes, scratches etc.  It also polishes up nicely for alclad.  If I don't prime, I usually regret it later...

Regards

Tim

[Black Knight]

Glancing thru these answers we have;

No

Never

Yes

Sometimes

Always

Occasionally

Rarely

Maybe

 

 

[Dads203]

I prime everything,  most if not all of my projects are multi media along with scratch building work so it’s required to give an even colour base before the top coats. 

 

The last time I painted onto direct plastic I was in my teen years 

[Corsairfoxfouruncle]

56 minutes ago, Black Knight said:

Glancing thru these answers we have;

No

Never

Yes

Sometimes

Always

Occasionally

Rarely

Maybe

 

 

Sounds like some of my “ex’s”

[Jamie @ Sovereign Hobbies]

I almost never prime. It is not necessary for adhesion with the paints I am using.

 

I will however spray an overall uniform coat of enamel paint on the exterior only to allow me to critique my seam filling and spot any surface finish issues before applying the colour coats towards the final finish.

 

It depends on the paint chemistry.

 

Plastic model kits are made from plastic polymers which have hydrogen and carbon content. Hydrocarbon containing paint can bond chemically to the surface of styrene plastics. Water based paints can't and are competely dependant upon a mechanical grip - i.e. if given a rough surface they will hold on to it.

[bmwh548]

Surfacer 1200 always for me. Helps a lot with showing faults and it provides a good surface for paint to stick to.

[Mike]

15 hours ago, Jamie @ Sovereign Hobbies said:

I will however spray an overall uniform coat of enamel paint on the exterior only to allow me to critique my seam filling and spot any surface finish issues before applying the colour coats towards the final finish.

 

It depends on the paint chemistry.

 

Plastic model kits are made from plastic polymers which have hydrogen and carbon content. Hydrocarbon containing paint can bond chemically to the surface of styrene plastics.

That pretty much describes a primer. I usually prime with something a bit whiffy that sticks like to a blanket, over which I apply the acrylics I topcoat with.  The only Acrylic primer I ever found that sticks like the aforementioned is Ultimate Primer, or Stylnrez (or however you spell it).  All the rest have very poor adhesion by comparison, and sanding them just ends up with the primer peeling off with the sanding action.

[Moggy]

The only thing I do that can be construed as priming is a coat of Tamiya light grey (acrylic of course) in order to get an uniform surface colour & check for surface defects. I've found that washing the kit parts to begin with and carefully cleaning up the surface with alcohol before painting gives acrylics an excellent grip... at least Tamiya & Gunze paint.

As a matter of fact I've tried to clean up Tamiya-painted models painted several years previously with alcohol - to no discernible effect!

I ended up sanding down the paint before covering it up with a new coat of .... yes, Tamiyal Light Grey

 

BTW I've tested Vallejo & Lifecolour paints when they were new to the modelling scene. My conclusion was - who needs paint made for plastic that will not stick to the plastic surface!?!?

 

Cheers, Moggy

[godzilla]

Thanks for all the replies guys I am using Tamiya acrylics at the moment and in general they do paint well but not that uniformly, might need to start thinning them a little bit first. 

 

I think on my next kit I will spray the whole sprue with the Tamiya fine primer and see if it makes any difference.

 

For some of the parts that said to paint semi gloss black onto already black plastic I cheated and just didn't paint them  haha