Should you apply a primer undercoat ?

[stiffy]

I'm just getting back into Airfix kits after about a 45 year break.

Back in the 70s as kids we would just paint the kits with Humbrol Enamel and move on to the next. There was never much finesse but we were happy.

Now a little wiser I want a better look so am experimenting to some degree.

So my question to all the sages.. Should you prime a kit that's moulded in a grey plastic before applying the top coat. ?

I don't want to loose the definition of the kit but one/two coat of Humbrol over the grey plastic looks a bit naff.

Cheers

[fredk]

I use a primer/undercoat if my top colours are acrylic paints, or if the plastic is bright colour

[iggie]

On the other hand, I only use acrylic and never prime...
The trick is to find what works for you and refine that as you gain experience, rather that just following others. As Fred and I have just proved, there are at least two ways to skin this cat, with lots more somewhere in between...

[AndrewR]

I use Vallejo acrylics, and priming is essential. It really depends on your choice of paint!

[JohnRatzenberger]

Lost my original reply.

If the underlying (base) coat is acrylic, then usually - rattle-can Tamiya Lt Grey works fine - hose down the whole kit, lightly, right out of the box and you are done. Clear parts excepted.
If the underlying (base) coat is enamel, then almost never (or I cheat with hull red overspray on ships).
If it's only detail painting, almost never.

See Fred's remarks about colors, that can be a big a problem as raw coverage.

As stated, let your experience be your guide.

[VickersVandal]

I use Vallejo acrylics, and priming is essential.

+2 for this. Vallejo needs a primer. I actually use a rattle can semi-matt white from the auto shop, which serves me well.

[stiffy]

Thanks for the input folks. I think its going to be a learning by the job.

I'm currently doing a Bond Bug kit. These are grey plastic however the main body is orange so the grey bleeds though unless a base coat is applied. I cant say I'm very impressed with the Revell Black paint I purchased -it seems to have a gloppy consistency- the Humbrol Enamel seems a lot better.

[VickersVandal]

For light/bright colours in particular - yellow, red, orange etc - I find that a white base coat is an absolute must.

[fredk]

I like gloss orange as an undercoat/primer for red or yellow, irrespective of the plastic colour

[Stuart]

An interesting thread this. Personally I would say that yes, if you're painting with acrylics then yes, a primer is a good idea (ether spray or brushed) as the paints are very fragile. That being said, quite a few of the kits I built last year I didn't bother - I just handled them carefully and touched up the scratched where needed. Once I sprayed on some clear coat to protect them, scratching is less of an issue.

[AndrewR]

I use Vallejo Sand Coloured primer for orange and yellow top coats. It works extremely well.

[Zee28]

Interesting question. I find a primer coat serves many purposes (I've sprayed classic cars, 1/1 scale, and never without a primer coat first).

A light dusting of primer sprayed on can reveal blemishes and flaws in the surface that may not have been seen or previously spotted to the eye and could spoil the final finish. And high-build primers can be lightly sanded to help remove seams or minor surface faults. So priming serves a valuable purpose there.

In terms of the final paint job, a primer provides a good base for your final colours. If you use good old fashioned enamels then it helps a bit, but not necessarily crucial, but if you use modern and more fragile acrylics then a primer coat to seal the surface and provide a key for the top coat can be considered pretty much essential. It also helps seal in any unhelpful impurities that might be present in the base material of the model and may not have been got rid of by cleaning and washing.

Then we have colour and, more significantly, colour density, and again primer can be helpful and will help them show their true colour. A white or sand coloured primer under yellow and orange, matt white under gloss white etc. etc. And reds can also be troublesome without a similarly tinted primer.

I suppose it all depends on what is required of a primer coat and what is needed. Is it for surface preparation or for colour density? It was a good question Stiffy, with no simple answer!

As for your Bond Bug in orange, then yep, I’d prime it before spraying the orange.