To prime or Not to prime, What IS the answer?

The basic problem is that there is no clear-cut answer. It boils down to two factors:

1. Personal preference
2. Results

If someone doesn't prime - as I do not - and gets satisfactory results, then they're happy and will probably advise others that primer is optional.

If someone always primes and gets satisfactory results, they're happy and will probably advise others to prime their models.

My question to you would be (rhetorically) have you gotten satisfactory results in the past when using or not using primer? If the answer is yes, then just keep doing what you're doing. If not, try something new, but I wouldn't be practicing on your "pride and joy".

I know this doesn't help much, but sometimes there is no easy answer.

Robert Foster

Robert gave a good answer to your question. I'm sort of in the middle of the road, I prime some parts (or areas) and not others. I always prime resin and PE parts, but not all styrene parts.

Priming offers two advantages, IMO:
o Primer gives the final coats of paint a good surface to adhere to. Acrylics don't adhere as well as enamels or laquers, and on the outside surface of an airplane I do not want the paint pulling up while I do all the finishing work (decaling, weathering, gloss / flat coating, etc.) I don't want to even have to worry about that happening.

o Primer makes surface defects show up like a sore thumb. I can sand and sand and get a surface to the point that I think it is perfect, but after I prime it I always find areas that need a little more work.

Whether or not to prime is your choice. Those are the reasons that I choose to prime sections of my models.

I usually don't prime, and to be honest, I don't simply because I'm too lazy.
Any PE/Metal, resin I tend to prime, especially metal figures. It's pretty much impossible for me to paint them without. However ,with the tank and aircraft kits, very few are primed. As MusicCity pointed out, priming will bring out the smallest of surface blemishes, so if you want a flawless finish, go for it.
Also, depending on colours you use, a primer coat may be very important, especially if you're using lighter shades, as the grey styrene will alter the colouration.

BY the way, if you're afraid of the primer hiding surface detail, may I suggest Tamiya fine surface primer, out of a white rattle can. It covers very well, but does not lay down a heavy coat. Great stuff!

When I use fillers, especially in areas where I've opened doors or where there are large seams, I do use primers; a light colored primer will reveal flaws that sometimes I can't either see or feel at all otherwise! I think I've done a great job, then lo and behold, the primer reveals an irregularity that has to be further corrected. Usually one, maybe two re-corrections are necessary.

Even if I don't use fillers, I like to prime large areas before painting as there might be a cosmetic flaw from the factory. But with small parts, I generally don't bother unless the plastic itself is dark-colored.

i prime for the simple reason that i cant see if i've filled all the gaps, puttied well, and corrected all the imperfections of your average kit without 1 color covering the whole model. Putting one solid color over the whole kit highlights areas that still need work before i get into really painting.

I go both ways, but I do clean every model (grilled Jr. on this also). By clean I mean soap and water (warm), and let it air-dry. Metal figurines/parts I use SImple Green, rinse, then sit.

Well Music City gave the good reasons why prime. I myself don't prime unless the model is molded in dark color plastic and I have to paint it a light color especially white or light gray enamels.

I forgot. Regarding wether priming will hide small details use an airbrush so that only a thin layer is applied. I don't use aerosol cans because the paint tend to be a little thick which may hide details.

Well I finally took the plunge and used a light coat of Tamiya primer. So far so good.
But whew, what a stink!

It depends on the model plastic, I think. The Academy models I've assembled are easier to paint because the plastic is not too smooth. Hasegawa plastic is a lot smoother and doesn't give paint a lot to bite with (yes, I always wash the parts to remove teh molding grease), so it's harder to paint. I suppose you can use some 2000-grit sandpaper on smooth plastic... Oh, in case you're wondering, I only brushpaint.

Back when I was into figures, I primed everything. And when acrylics first came out I discovered that you had to either lightly sand the entire model or apply a coat of primer cause the paint would just puddle like rain on a freshly waxed car. Now adays I only prime if I do some major alterations and/or puttying. Does two things for me - lets me see any errors I have missed and serves to fill the putty. (putty will some time soak up the paint when applied causing that area to look different than the surrounding plastic)

When I do prime, I use a good automotive primer - usually in light grey.