To prime or not to prime?

Tools, Techniques, and Reference Materials Painting and airbrushing
1

I know primer will help adhesion. I tried airbrushing Tamiya on 2 spoons, one with primer, and one without. I painted the primed spoon with Gloss black, the other non primed one with Gloss red. The one with the primed spoon did not budge, meaning it is very scratch resistant (the black). The red one without the primer did not do well, it scratched in the slightest pressure.

This leads me to the next question. Do I have to prime every part? Yes, it will make surface adhesion better, but there are so many parts. But, if I don’t prime them, then it would be easy to scratch the paint.

So how do you make it so the Tamiya Acrylic paints adhere better to the surface without primer?

2

If I’m hand painting small plastic parts, I do not prime. Any large parts or assemblies get primed before painting. All metal and resin parts need primer. I use Gunze Mr Metal Primer on hand painted metal parts, and Tamiya lacquer primer in a bottle for hand painted resin parts.

To help ensure paint adhesion, you should wash the parts in an unscented dish soap that contains no hand lotion. I use Ivory. This is to remove any mold release, hand oils, etc. that could be on the parts.

I don’t generaly wash metal parts and never wash photoetch. Not a rust issue. I actually don’t have a good reason why. :slight_smile: I just haven’t and haven’t had any issues.

Mike

3

If delicate paintwork is the problem, and using primer is the solution, use primer. Having lots of parts is central to modelling but, if that puts you off, try assembling parts into sub-assemblies first - e.g. cockpit, engines, (or hull/turret) etc. - then prime the sub-assemblies. Or prime everything all in one go while still on the sprue (after washing in soapy water). Personally, I use the sub-assembly approach - and still wash the sprues first.

4

Does regular dish soap work as well?

5

When in doubt prime. In addition to aiding adhesion and smoothness it protects plastic from hotter paints like lacquer.

I do get by hand painting small parts without priming- I use Testors enamel, known for its brushability.

6

I think that may be because with photoetch, it’s already a given that it has adhesion issues, so we handle it delicately.

Bill

7

I never washed a sprue or a model in my life and never had any problems,so that’s a choice.

As far as priming every part, not usually.Not tiny nobs or handles in a cockpit,but I will prime the completed sub assembly,same with tiny armor accessories I won’t prime them individually but as part of an assembly.But if I’m just adding one part later,no I wouldn’t prime it.

8

My typical approach. Once a part comes off the sprue, it’s easy to lose it.

Bill

9

Wash or wipe off with alchohol and always prime. You will never be sorry you primed something first. Not priming is just skipping a step to make it quicker, you are not making it better by just painting. I always prime now, no exceptions. I no longer have adhiesion issues and I can control the color better. Just my two cents.

BK

10

I’ve only ever used Ivory dish soap. Other brands should be just fine. You don’t want it to have any lotion for your hands in it, because that will just grease up the parts. I’ve been told to avoid scented dish soap, but I haven’t tried it out.

Mike

11

That’s the way I look at it, too.

Once, I was sorry I didn’t prime something, and the model was almost done, and that’s not an experience I care to repeat.

12

Yes just to note, my post above is based on tests I conducted but in my models I prime everything that will get color regardless of type of paint I will use… For small parts I leave them right on the sprues. I just scrape off what I can of any flash if there is any and later touch up the cut off points if they show. I often paint color on the small parts right on the sprue as well.

13

[dto:]

I never bother to prime fuselage halves and wing parts while they are on sprue- I know they will have seams to contend with.