Primer problems – help please

[Norm S]

I use Vallejo acrylic-polyurethane as a primer on all figures.

It is fine on plastics.

it is fine on Kallistra metals, which are made from lead free pewter.

But on all my other metals, it is easily scratched / rubbed off, even after paint is applied, the high points end up with the base metal showing through.

For those who know such things, how come it bonds so well to plastic and lead free pewter,  but not with my other stuff? I wash everything (and scrub) with hot soapy water.

[Mike Headden]

All of my stuff is either metal, resin or hard plastic. Never washed any of it in a painting career that spans around half a century. I don’t use primer as such but spray paint an undercoat using Halford’s Black or White matt car paint (very, very occasionally a coat of coloured spray paint actually designed for figures) and after painting I use a spray of artist’s or gaming matt varnish, final touch up of shiny bits with gloss varnish completes it. I have figures that have shoogled around in a box through three house moves and umpteen moving of the box they are in with no noticeable loss of paint.

So, not sure why it’s a problem – sorry.

tl:dr Don’t know Norm, doesn’t seem to happen to mine. 🙂

There are 100 types of people in the world, those who understand binary and those who can work from incomplete data

[vexillia]

The surface of lead, and its alloys, is very smooth compared to ferrous metals.  Copper, brass and aluminium are similar. This makes paint (or primer) adhesion really difficult and special formulations are required containing additional binders.

These blog posts provide more background on the issue:

• http://blog.vexillia.me.uk/2008/05/painting-tips-2-primer.html
• http://blog.vexillia.me.uk/2009/01/painting-tips-3-primers.html
• http://blog.vexillia.me.uk/2016/06/painting-tips-8primer-update.html

I’m sure there’ll be a few recommendations for various spray primers etc. Just beware that if they are formulated for the motor trade then good results on toy soldiers are the result of good fortune or the adhesion has never been tested before painting starts.

If you want to get really serious about priming then etch priming is the way to go but these contain acid and should be used with great care.  From my article The Unvarnished Truth, Miniature Wargames, 369, 57-60:

“For those of you who prefer to spray prime then I suggest you consider using etch primers rather than standard car primers. Popular with railway modelers for painting brass parts, these contain acids which react with the surface creating a microscopically rougher surface that aids adhesion. The phrase to lookout for is something like “ideal for improving adhesion to problem substrates: aluminium, galvanised steel etc“. When buying do be aware they have a use by date and allow for a much longer drying time than standard primers. Etch primers are also available as brush on products.”

Good luck!

Martin Stephenson

[Mike]

vexillia wrote:

I’m sure there’ll be a few recommendations for various spray primers etc.

Here is one now  😀

Humbrol spray paint.
I have never had any issues on any material to date, I also find it thinner than car primer and as such less prone to clogging up detail.

 

[willz]

Norm does the figure manufacturer use a release agent, maybe some of that is still on the figure.  I have always wire brushed my metal figures before I undercoat and for 10+ years I have use acrylic spray primer (normally grey) as an undercoat.  Also I leave my undercoated figures to dry for several days if not months before painting.

 

[Norm S]

I remember reading somewhere that car primer has a built in ‘filler’ and that this can remove detail, so I went for the Vallejo primer, but it is very thin as it can be airbrushed. I have done the ‘scratch’ test with 3 manufacturers and on all the primer has failed. THe wire brush would probably give some key, but since I use 10 – 15mm, there is also the problem that I will likely take my fingertips off 🙂

Martin, I enjoyed your links and have just shot out to buy Hammerite Special metals primer. This seems to have all the qualities that you mention – and will even do chrome and stainless steel. It is also low VOC and brushes can be washed out in water. It is touch dry in 30 minutes and can be overcoated in two hours. Anyway, it has given me some hope and the trials continue. I will report back in case this helps others.

[vexillia]

I remember reading somewhere that car primer has a built in ‘filler’ and that this can remove detail

Quite right but there are two types of car primer: standard & build.  The latter are designed to be sanded after application.

have just shot out to buy Hammerite Special metals primer

I see you’ve gone for the expensive stuff. 😉

I will report back in case this helps others.

That would be great.

 

Martin Stephenson

[Norm S]

Mike, if this Hammerite stuff fails me, I will get a humbrol can, since you can’t get better than personal recommendation.

I have just applied it to a few figures, so will let it harden and see how I get on (the Hammerite is a sort of browny red colour.

[Mike]

Norm S wrote:

Mike, if this Hammerite stuff fails me, I will get a humbrol can, since you can’t get better than personal recommendation.  

well that rather depends…   😀

[Katie L]

If using spray primers, I go for Halfords satin black. It doesn’t thicken the way the filling primers do, and it seems to dry to a tougher finish than the matt black — it’s less “powdery” and seems to adhere better on those corners.

[Author]

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