Acrylic Primer for Airbrushing

[Guest]

Hi all,

I've had a quick search around the web looking for an acrylic primer which can be airbrushed on but can't seem to find any.

At the moment I'm using Halfords Grey Plastic Primer which does give a decent finish but the cans are so powerful when applying the spray it goes everywhere and even blows the model about! Not alot of control involved at all.

Can you guys recommend anything?

Atb, Colin.

[Guest]

Hi Colin

I use Vallejo primer which airbrushes very well. Not thick & gives a good smooth surface unlike some primers.

It is marketed in grey black & white.

Laurie

[Guest]

Just had a quick look Colin & John stocks all of the primer colours at the Shop.

Laurie

[stona]

I usually use the Halfords plastic primer myself. I was given some of the Alclad primer by a friend to try and was very impressed with it. It gave a very smooth finish and was well attached to the plastic

I'm not sure that anything bonds to the plastic like the Halfords stuff,talk about sh*t to a blanket!

Cheers

Steve

[Guest]

Must admit that Halfords stuff is strong.

How does the Halfords primer finish compare to the Alclad?

I was looking at the Tamiya spray cans and wondered if they had a bit more control.

[Guest]

Thanks for the heads up on the Vallejo primer Laurie, I see they do it in Model Air too so no thinning required.

Do you find it sticks well to the plastic?

[Guest]

I'll second the vallejo primer, I think it has a very small particle size and so you get a very thin coat, and I have never had any issues with adhesion or peeling.

[tr1ckey66]

Hi Colin

Vallejo primer is a good acrylic-urethane primer. I found it thin and needed to be applied in coats - which is great as detail is retained. It is not however as tough as the automotive stuff. For most of your modelling needs though this stuff is good and comes in a variety of colours, the white being particularly useful, and I believe they even do a Panzer dark Yellow now!? One other advantage to airbrushing a primer is that you can get into all the awkward and hard to reach bits easier.

Hope this helps

Paul

[Guest]

I'll third the Vallejo Model Air primer works very well, also the Alclad primer is just as good just make sure you have a window or two open as has a bit of a strong pong to it.

[Guest]

Squirt the Halfords stuff into the plastic lid then pour it into your airbrush, it goes on like a dream though the airbrush will need a proper clean afterwards

[stona]

There is a slight risk of getting a grainy finish with the Halfords primer in some areas. I have been told this is due to turbulence around areas like the wing roots. It has happened to me but it is such tough stuff that it can be polished to a glass like finish with some fine sanding and a rub with some old denim.

The Alclad stuff,which does indeed pong a bit,gave a very tough and smooth finish on the one occasion that I used it.

Cheers

Steve

[Guest]

Thanks for the heads up on the Vallejo primer Laurie, I see they do it in Model Air too so no thinning required.Do you find it sticks well to the plastic?

Stickability. You may already be aware of this Colin is so I am boring you.

The basis of all good paint systems house painting, car body work etc relies on it's background. The best primer in the world will have the potential to fail if the background is not right.

Plastic like fibreglass is one of the worst backgrounds to paint. It also has a high coefficient of expansion. So you need a primer which has a close coefficient of expansion. Provided the manufacturer of paint for plastic models has done his job then the primer paint should be compatible. Why you should not encourage drying to quickly as you then exaggerate any difference in the expansion coefficients resulting in poor adhesion & at worst cracks or vice versa wrinkles in the paint where the substrata has expanded more or less than the paint. Probably no so bad with 1/72 but getting to 1/32 there are more than twice the lengths of plastic.

Good practice to use the same manufacturer for priming & finishing. There then is no likelihood of a fight between the two. Experienced this with one primer I used at the time of my first model which then dropped itself into the dustbin.

ICI for instance recommend gloss paint as a primer coat for Plastic guttering as it has a similar expansion rate. Not sure about auto paints as they are designed for metals although obviously you cannot argue that one if they succeed & do their job on plastic.

From my point of view it is the preparation. I find that is the most important. I use an 1800 gauge wet & dry paper (wet) which has already had wear & paper the whole model very lightly. This will provide the best surface for the paint to adhere to. I normally only give one coat of Vallejo primer as I find this gives a good grip for the finishing coats. They do say wash the parts but by the time you have wet & dry papered there is no need. I use a body shop tack rag to rid the plastic of all the little sanded bits.

Laurie

[stona]

Not sure about auto paints as they are designed for metals although obviously you cannot argue that one if they succeed & do their job on plastic.Laurie

Important to point out that the Halfords primer I use is "Plastic Primer" which evidently is designed for use on plastics. I think it may even chemically etch into the surface. I have used it under acrylic,enamel and lacquer finishes with no problem. I once removed a botched coat of acrylic paint using various solvents and a tooth brush and the primer was unaffected.

It sands and buffs up to a smooth finish (same method that you use followed by denim cloth) with enough of a key for subsequent coats.

Cheers

Steve

[Guest]

What's the technique with the denim cloth then? Do you just buff the surface of the denim or do you give it a light sand first?

Thanks, Colin.

[stona]

I give it a rub down with 1500-1800 grit wet'n'dry and then a once over with a bit of old denim (dry). I used to faff about with fine wire wool but don't bother anymore. I also usually wash the model under the tap and dry it. Then I give it a thorough wipe over with an alcohol moistened cloth to remove any finger prints etc before painting. Alcohol (IPA) doesn't effect the Halfords plastic primer but it might some others! You end up with a surface that feels very smooth but to which subsequent coats of paint will adhere very well.

It's just like painting your skirting boards really,it's all in the preparation.

Cheers

Steve