Need a primer on primer

[eastmanace]

Since my return to the hobby last year and maybe a dozen or so models completed, I'm generally satisfied with the finishes on each ( mostly 1/48 Navy jets). None of these builds had a primer coat prior to the finish paint with the exception of reworked areas that were spot primed with the same paint I used for the topcoat. I'm wondering if a complete primer job before paint will yield a smoother more realistic scale finish than a paint job without. I do know that in my line of work we will NEVER topcoat paintwork on a yacht without an epoxy primer coat. If indeed primer is the way to go then here are a few more questions: what type of primer to use?( I spray all of my models with MM enamels with a Paasche VLS)...What's the proper thinning ratio and with what thinner?........should primer coat be sanded/wet sanded prior to topcoat? .....and finally, what about surface detail? Will even a light primer coat, properly thinned, add to the buildup of paint that could hide small surface detail? I know that I could rescribe (lightly) recessed panel lines to compinsate. So........Is priming as important a factor in smaller scale paint jobs as it is in the "real world" or are the benifits (if any) worth the effort? Thanks for any feedback, Cliff

[GGoheen]

Greetings Cliff and welcome back to the wonderful world of modeling. As a fellow builder of Navy planes I can say that priming your models before final paint makes all the difference in the world in terms of finish quality and appearance. However, as one who used to rely on the same set-up you are currently using (MM enamels through a Paasche double action airbrush) I too used to worry about too much paint building up in the finely engraved panel lines. There was a point too where I'd actually re-scribe the entire model prior to priming so as not to loose this delicate detailing.

However, as the saying goes, you get what you're paying for too. Now that's not meant as sarcastic or to disrespect those using Paasche airbrushes or MM enamels. The point, however, is that when I switched to an Iwata airbrush and acrylics (Gunze) I was amazed at the amount of control one has over the amount of paint applied. Quite seriously I can (and do) put down 2 coats or more of primer, then another 3-4 coats of the aircrafts final color/markings, seal with 1-2 coats of Future and still not fill the panel lines unless exceptionally heavy with the hand while spraying.

Considering the set-up you currently use, you should be able to lay down a nice, even coat of primer (you pick....MM Dk Gull Gray was one of my favorites)...make sure you're happy with the results and are free of any blemishes......putty and wet sand those you may have....then just proceed to paint. The real key is super light coats, despite the urge to cover your kit in one.

Hope this helps.

Sincerely,

Greg

[Edgar]

Until you're confident, enough, to experiment, your best bet is to use the manufacturer's thinner. As for the ratio, it's impossible to say, since it will depend on ambient (room) temperature, spraying pressure, etc. I spray (U.K.-available)enamels through a VL, at 20psi, and find 2:1 paint to thinners about right, for matt paints, and around 50/50 for gloss. If you have a spare glass bottle, or an old see-through 35mm film container (remember them?) mix some paint, with the thinner, and then "swish" it round (with the lid on, of course!) Watch the behaviour of the paint; if it sticks to the side, and doesn't move, it's too thick; if it slides, slowly, down the side, leaving a slightly translucent film, it's about right; if it drops straight back down, it's too thin.

Again, this applies to the U.K., but we have a supplier of spares, to the motor industry, and they supply a selection of primers, for plastic parts (vital to remember that!) Though it comes in aerosol form, it's surprisingly fine, and one coat is normally sufficient. As it dries in about 10 minutes, it's easy to sand down, lightly, with (wet) Micromesh, which gives it a smooth semi-gloss finish. If necessary, a scriber can be whisked, free-hand (honestly,) through the panel lines, and the excess removed with a damp cloth. I always prime, since it enables me to see any areas, which I might not have filled, or haven't sanded down properly, and, when it comes to Alclad, I know that it won't touch the primer.

Edgar

[Big Kev]

I'm a new returnee to the hobby too, and have also recently started using a primer on my models. I'd like to see a distinction made however between a simply monotone undercoat using ordinary model paint, and an actual primer coat. The way I see it, proper primer is something apart from simply your model paint of choice applied in a light grey colour - it should have the ability to bond to all kinds of surfaces (plastic, putty, etc), dry smooth and hard, and offer 'bite' for more fragile top finishes (eg, most acrylics).

Based on that, my primer of choice at the moment is Mr Surfacer (I use 1000 out of a rattle can). It seems to possess most of the qualities listed above, but is expensive and a bit wasteful in its rattle can form. Here's an example on my current build:

I'd actually like to find a decent alternative that I can use more as an undercoat, for models that don't need the added benefits of something like Mr Surfacer - kits I haven't been 'bashing'. I know in the US and the UK, automotive primers are popular for this task, but I can't seem to find anything suitable here in Australia. Since I paint mostly with acrylics, lacquer-based primers and undercoats are the best options, but I guess a standard grey enamel hobby paint would be sufficient.

Kev

[David TR66]

I use Alclad grey primer and micro-filler, it goes on great, dries quickly and gives a tough, satin finish. You can use it directly from the can as long as you shake it well. I've put it through my Aztek and my Iwata with no problems. Use liquid reamer or spray-away to clean up and make sure you use a decent respirator when airbrushing.

[Donnico]

I use floquil reefer white as a primer. Cheap, sprays well, and can be wet sanded to a semi-gloss if you so desire. I especially like that the white base coat offers a good contrast background for preshading, leading to more "durable" preshade lines once you lay down your color coat. Its especially good for a modern Navy TPS.... just preshade the model after the white primer and add random streaks and splotches.