primer Is a Primer( Grey) really necessary for models?

[doorslammer68]

I've debated whether this is a necessity or not. Takes more coats of paint to get the desired color. Your comments are welcomed. Thanks

[johnyrotten]

It's a good idea. Some brands/types of paint have "hot" solvents and can cause problems,  and certain kinds of paint like cheap craft paint almost "require" it for any kind of adhesion. It will also help find flaws in bodywork, sink marks and such. I use cheap hardware store primer that I've decanted. 

[64SS350]

I guess first off you have to decide what level of quality you want to build at. If you just enjoy building kits with minimal paint prep, than no, it's not "necessary". Build and have fun!

If you want better paint jobs, prep work is needed, ie; sanding mold lines and oddities in the plastic, filling voids or sink marks.

Primer does a lot. If using hotter paints like lacquer, it puts a barrier between the plastic and the paint to prevent possibly melting it. Some fillers require primer first for the same reason.

If a paint job goes poorly, primer makes it easier to strip the paint back off.

It can act as a leveling agent when block sanding a body. 

As far as more coats to achieve a desired color, use different shades of primer....white, light grey, dark grey, red, black.

Hope this helps, I'm sure others will chime in also! Happy building!

[Brutalform]

There is always white primer. Also the Tamiya pink primer really makes different reds lay down nice, and the color pops. 

[TonyK]

The above answers are true. For me, most of my models are kept simple so I just sand all the mold lines off, then wash the body, and I'm most likely spraying Testors or Tamiya paint from the can and it lays on the bare plastic just fine.

So you can take all the suggestions you get and use them according to your building preference.

[peteski]

When I use mild solvent-based paints (Testors, Tamiya), I avoid using primers as much as possible.  To me the fewer coats of out-of-scale-thickness paints, the more realistic the model looks.  But many modelers use hotter paints, and with those primer is required, or they will attack bare plastic. Water based paints also require primer as most do not adhere well to bare plastic

[StevenGuthmiller]

Let’s put it this way.

Nothing is “necessary” when building a model.

You can brush paint it with latex house paint and glue it together with cheese whiz if you want.

But, if you want to do it right?......well, I’ll just say that there are a number of reasons for priming anything that you’re going to paint, whether that be a house, a real car, or a model car.

Primer doesn’t exist just to sell primer.

Of course, if your spraying a benign paint such as an enamel or a water based acrylic, if you can get it to look decent over bare plastic, it’s not going to hurt to skip the primer. (That is if you’re not worried about the paint falling off down the road)

But if you plan on using a lacquer of some sort, you darn well better plan on priming unless you love taking unnecessary chances with your expensive models.

As I’m sure you can tell by my attitude in this post, priming is one of the processes that I would NEVER skip, but hey, you do you.

 

 

 

Steve

 

Edited September 25, 2024 by StevenGuthmiller

[Ace-Garageguy]

  Primer's not even "necessary" on a real car.

You can paint directly over bare steel, dirt, sanding scratches, and bondo if you want your car to look like it was painted by a bunch of drunk monkeys or 5-year-olds.

The question is...how much effort are you willing to put into a project to make it look like it was done by a competent adult who had some concept of "quality"?

Edited September 26, 2024 by Ace-Garageguy

[Dave G.]

Beyond everything that was mentioned above, I've done scratch tests with waterborne acrylics, alcohol based acrylics, lacquer and enamel paints. The tests, taken over a couple of months time, were done with the various paints airbrushed directly to plastic and then sprayed over two light coats of primered surface. Two different primers were used, Mr Primer Surfacer ( a lacquer), and Stynylrez poly acrylic. In all cases the paint sprayed directly to plastic scratched easier in the samples with no primer. In the case of Testors enamel, was the surprise product, it scratched only slightly harder than alcohol acrylics. I was very taken back by that fact. Also the fact that waterborne acrylic shot on primer did amazing well, especially on the Stynylrez. Not surprising in one way, lacquer did pretty well upon initial scratch testing on bare plastic, but once breaking the surface the scratch continued pretty easily.

Waterborne on bare plastic ( craft paints in particular, were horrible). But surprisingly resilient when put on Stynylrez primer. Quite good really, better than Testors enamel sprayed direct to smooth unprepped plastic.

I conducted another test as well. This was kit plastic vs various household plastics shot with a coat Mr Surfacer. Mr surfacer far out tested scratch testing to AMT kit plastic, than it did any household plastic, including my infamous prescription bottles. It really did not do well on any plastic but the kit plastic, confirming to me that product is truly model based and worth owning for only that purpose. But well worth owning for it.

These tests are far from fully comprehensive, I'm not claiming that. There are many combos not tested, and while I did test hot lacquer as well, I didn't include that because I would never spray that directly to plastic. The tests were for my own satisfaction, to help understand what paints work best in what combo. But thought I'd share it here. No pressure measuring tools were used and scratch tools were simple, my untrimmed thumb nail ( yes some scratched that easy) or a pocket screw driver, to which with the screw driver any of them could be scratched, just a matter of how easy or even if entire areas scraped off in the process... And if you've read this far, God bless you, you must be as crazy as I am !

Edited September 27, 2024 by Dave G.

[MeatMan]

I almost exclusively use primer because the few times I've tried to paint w/o it, I don't like the result 90% of the time.

[doorslammer68]

Thanks to all of you for your thoughts; very grateful. Steve LOLLLL the cheez whiz was gold lollllll. I will prime from here on and won't skip it. I'll share my AMT 68 Pro Street Roadrunner in parts. AMT for some reason you have to glue the chrome rear window pillar; A ROYAL PAIN IN THE ASSS!!! I'll foil it separate then after body is painted then tack it in. Too brittle any other way. Window frame under roof will touch the edges so I may have to file a notch to fit. Stay tuned and thanks to all of you. 

[doorslammer68]

[StevenGuthmiller]

2 hours ago, doorslammer68 said:

Steve LOLLLL the cheez whiz was gold lollllll.

I must admit that I kind of stole that line from Bill Engwer.

 

 

 

Steve

[Fat Brian]

Be sure to wet sand your primer before the color coat. I wasn't a believer in primer because every time I used it my paint came out pebbly-er than a dirt road. Finally I took the advice to wet sand my primer and it was a game changer. 

Edited September 26, 2024 by Fat Brian

[James2]

The number one key to a successful paint finish is prep! And primer is part of the prep, among other things. The thinner the thickness of primer/paint the more detail shows through. I find that airbrushing helps to keep paint thickness at an acceptable level, but preparation is still the key, I will prime and sand just about every part. Tamyia primer is my go to, and they have several colors including pink. 

[bluenote]

I don't typically prime except for the body.  I'm wondering now if I should give all the parts on the sprue a coat of tamiya rattle can primer before painting....

[Dave G.]

7 hours ago, bluenote said:

I don't typically prime except for the body.  I'm wondering now if I should give all the parts on the sprue a coat of tamiya rattle can primer before painting....

I prime the whole kit minus the body first thing, only Mr Surfacer or Stynylrez. The body is a treatment in itself, and will get either Mr Primer Surfacer, Mr Surfacer or Stynylrez primer, depending what paint the body will be shot in. Painting on the sprue you need to at least scrape any flash off the parts. Then touch up later nipped sections. This all started for me decades ago just to get the plastic glow off the parts. Then grew from their.

[peteski]

Priming every part seems like such a waste of time for me, but since it is a hobby, if someone enjoys doing that, the more power to them.  To me there is absolutely on reason to do that, plus as I mentioned earlier, every additional coat of the 1:1 scale paints (including that primer) adds to the totally out-of-scale thickness of paint applied to our smaller scale models. The thinner the paint coating is on the model, the the more realistic the model will look. That's my theory, it works for me, and I have not reason to change.

But I use old-school solvent-based paints which adhere well to bare plastic. Many modelers today are using water-based acrylic paints which might need a primer coat which will provide better bond with plastic.

Edited September 27, 2024 by peteski

[T-Ray]

I can't help but feel like the primer should go with what's going on top of it. White primer for light colors, grey for darker ones. That's what I do anyway

[gtx6970]

Myself it all depends on the type of paint Im using. If its straight old fashion Model enamels. I'll clean and spray right on bare plastic.

 

Pretty much anything else. Primer first , Typically I use Duplicolor primer sprayed right out of the rattle can

To be honest, I use a lot of Duplicolor rattle can paints as well , I dont own an airbrush

Edited September 27, 2024 by gtx6970

[bobss396]

Some smaller 3D printed parts I will not prime. The surface takes paint well.

Anything else I will prime first. I recall using candy paints as a kid... I was not hip that they required a gold or silver under coat.

[Rick L]

Primer is helpful for the reasons above but primer (grey) specifically is not necessary. It depends on the top coat color being used. An example would be painting canary yellow over grey primer would give you a green tint. A white primer should be used. 

[Dave G.]

Despite my lengthy post further up the list, I never addressed the actual topic at hand, grey primer and the word necessary. To that the answer is no to how the question is presented. You don't have to use grey  primer or any other primer at all. In fact you don't have to do anything, hobby paint, no. Auto paint, no, spray, no. You can dip the thing in house paint if you like, or build it no paint at all, or just collect kits and never build them. For that matter, walk away. it's your model, your hobby, your way. And the bottom line is many folks just do as they please and are happy doing it that way. And it matters 0 to them if it's practical or not. Some folks for that matter, enjoy living in the infancy of the hobby, they like it right there. Maybe it's nostalgia or whatever that attracts them.

[oldcarfan]

For me it's necessary. My paint jobs aren't that great, but the primer lets me catch a lot of mistakes before they happen. I prime, sand, then wait for the sun to get to the right spot and I can then see mold lines and any places that need attention. It also allows for better paint coverage.

[bobss396]

I use primers that go on thin and cover well. As not to lose detail, I like Tamiya and Mr. Hobby primers.