Spray Primers - Citadel is Awesome

[sal4m4nd3r]

2 hours ago, Kaleb Daark said:

please could you define primer vs paint?

Primer is chemically formulated to bond to plastic. This creates a surface that not only chemically bonds with plastic but also paint. So your paint won't chip and will go on smoother

[HeadHunter]

5 hours ago, CoffeeGrunt said:

No reason to wash plastic as you don't use release agents on plastic injection moulds.

Unless you're handling them with gloves on, you're getting the oils from your skin on all the parts as you assemble them - and dust from sanding, cleaning mold lines, etc.  That can affect the way paint bonds as much as any release agent.

[Carnelian]

I believe the latest White Dwarf has an interview with a golden demon winning painter who mentioned that he doesn't use any sort of base spray at all - be it primer or not- and that he just starts building up thin layers of paint on the model straight away! 

I think that's pretty unusual but it goes to show there are many different techniques open to paints to get different effects.

Personally I love the gw colour sprays as a base. Used zandri dust an awful lot to spray my undead and for skeltons all you need to do is then colour the silver and wash with agrax and they are instantly playable 

[CoffeeGrunt]

6 hours ago, HeadHunter said:

Unless you're handling them with gloves on, you're getting the oils from your skin on all the parts as you assemble them - and dust from sanding, cleaning mold lines, etc.  That can affect the way paint bonds as much as any release agent.

I have never seen a model fail to take because of the oils on the hands, mainly because fingertips have the least amount of sebaceous glands in the body and the palms of the hand have zero. 

In fact the vast majority are on your face, so unless you're assembling them with your face, you should be fine.

[DynamicCalories]

That reminds me that one of the guides out there for using greenstuff talks about the author hearing of a person that used their own forehead oils as lubrication during the molding process. Yuck. 

[Carnelian]

17 minutes ago, DynamicCalories said:

That reminds me that one of the guides out there for using greenstuff talks about the author hearing of a person that used their own forehead oils as lubrication during the molding process. Yuck. 

If my fingers get sore playing slap bass now I know where to easily lube them! Great tip

[Kaleb Daark]

23 hours ago, sal4m4nd3r said:

Primer is chemically formulated to bond to plastic. This creates a surface that not only chemically bonds with plastic but also paint. So your paint won't chip and will go on smoother

In a manner of speaking yes, however technically speaking a primer is a paint; namely a coat of paint that is applied directly to the bare substrate.  It is in essence the first coat of paint hence 'primer' and it's purpose is to provide an excellent (mechanical rather than chemical )adhesion  to the substrate for the new paint system - and more importantly allow compatibility of adhesion for the paint system you intend to use  . Primers therefore need to have good adhesion to the substrate themselves and to provide a surface that subsequent coats of paints can easily adhere to.

What you're alluding to is an etch primer which is almost a pre-primer coat which allows non compatible paint systems to adhere to the substrate, which in this instance is plastic, which if @RuneBrush is correct, (quoted below) then the citadel black and white is indeed a plastic etch primer.

In fact, halfords do a plastic primer which is a plastic etch primer in all but name.  In the world of grown up spraying etch primers are almost as thin as water, basically just allowing the surface to be prepped to receive the high build primers which follow.  You don't hi build for what we're doing- so really just an initial etch of the surface substrate is more than adequate.

On 2/20/2017 at 0:08 PM, RuneBrush said:

Putting a technical nerd hat on, Citadel cans (at least the Black and White) contain an "etching" chemical, which lightly softens (etches) the surface they're sprayed on to create a really firm bond.  If you've ever oversprayed something and tried to wipe it off straight away, you'll discover that you mess up the surface of the model.  To my knowledge, none of the other brands have this etching chemical.

Completely agree that they're not a primer in the truest of senses, but for plastic models you can't go far wrong.

When undercoating resin, they don't etch in the same way so I tend to put a layer of matt/satin varnish down first (highly recommend Plastikote Clear Sealer for this) and then Citadel over the top.

I generally find that resin models are ok, but I'm under no allusion after having messed around with resins and advance composites for over twenty years that soapy water generally doesn't cut it with removing extremely stubborn release agent residue on components - especially now that most release agents are water based for Health and safety reasons.  I find the supports are a good way to test if you've cleaned the part well enough as if the paint won't hold on the support it won't hold on the model either.  In very stubborn cases I've used IPA and extreme cases I've used brake cleaner (3M 7063 or similar) as it's high flash point means that the part remains spotless and residue free (we used to use it for structural bonding preparation).

I tried FairyPS once on a fine cast skulltaker and after a soak it basically turned it into a pencil eraser - I've still got it and its like a piece of rubber,  and so now I use support sprue as test pieces for anything I'm not too sure of.

[HeadHunter]

On 2/25/2017 at 7:13 AM, CoffeeGrunt said:

I have never seen a model fail to take because of the oils on the hands, mainly because fingertips have the least amount of sebaceous glands in the body and the palms of the hand have zero. 

If that were true, you'd never see a handprint on a window or the door of a store.  It's not as if metal or resin models come packed in cosmoline, either.

[CoffeeGrunt]

1 hour ago, HeadHunter said:

If that were true, you'd never see a handprint on a window or the door of a store.  It's not as if metal or resin models come packed in cosmoline, either.

Sebaceous Glands don't exist on the hands.

If you wash your hands to remove any substances you may have come into contact with, then the problem will not happen, and unless you've chowed down a Bargain Bucket, it's highly unlikely to happen anyway.

[HeadHunter]

But they do exist to some extent on the fingers, to the point that cysts can form.  But notice I said "oils from your skin", not just fingers.  Yes, washing your hands is important - but unless you wash them immediately before handling a sprue or part every time, it's going to happen,  

And while some people claim that there's no need for mold release on injection-molded plastic, there's no proof of its absence.  There are a variety of products made and sold specifically as release agents for injection-molded plastic.  What makes anyone think paint will adhere any better than the mold did?

Regardless, I see no possible harm in washing the sprues before painting them, and it's worth the benefit even if it's debatable to some.

[Kaleb Daark]

14 minutes ago, HeadHunter said:

And while some people claim that there's no need for mold release on injection-molded plastic, there's no proof of its absence.  There are a variety of products made and sold specifically as release agents for injection-molded plastic.  What makes anyone think paint will adhere any better than the mold did?

Regardless, I see no possible harm in washing the sprues before painting them, and it's worth the benefit even if it's debatable to some.

The only people that may claim you don't need release agent is the person who has never had to lose a mould due to a part sticking.  Those moulds cost the wrong side of forty to fifty grand per sprue depending on how many units you want out to them.  The service life of a cheap one is around 50,000 pulls -  so you want to look after them.

In injection moulding of plastics the release is totally dependent on how much the customer spends on the mould, it can be a simple aerosol application say every hundred outputs, or more than likely a permanent coating on the surface - think teflon but a few of microns thick - that way the mould can be constantly cycled.

It's easy to get precious about such things, and there is absolutely no harm as you say in washing plastic sprue.   At best there is a benefit, and at worst you have lost nothing

2 hours ago, CoffeeGrunt said:

and unless you've chowed down a Bargain Bucket, ...

reet funny that

[Soulsmith]

Wow seems things are getting heated. That's bad for the primer guys [emoji2]. Each to their own I would say. Personally I prime in gloves but purely because I hold the miniatures. I tried to paint once in them but my hands got too sweaty, I try not to hold any part that's finished and I've never rubbed off primer.

[RuneBrush]

On 26/02/2017 at 0:59 AM, Kaleb Daark said:

I generally find that resin models are ok, but I'm under no allusion after having messed around with resins and advance composites for over twenty years that soapy water generally doesn't cut it with removing extremely stubborn release agent residue on components - especially now that most release agents are water based for Health and safety reasons.  I find the supports are a good way to test if you've cleaned the part well enough as if the paint won't hold on the support it won't hold on the model either.  In very stubborn cases I've used IPA and extreme cases I've used brake cleaner (3M 7063 or similar) as it's high flash point means that the part remains spotless and residue free (we used to use it for structural bonding preparation).

I tried FairyPS once on a fine cast skulltaker and after a soak it basically turned it into a pencil eraser - I've still got it and its like a piece of rubber,  and so now I use support sprue as test pieces for anything I'm not too sure of.

Finecast is a different conversation entirely   Forge World doesn't actually wash any of it's models, instead they just give them a coat of varnish/sealer (either purity sealer or Plastikote clear sealer) before applying the undercoat.

[Kaleb Daark]

19 minutes ago, RuneBrush said:

Finecast is a different conversation entirely   Forge World doesn't actually wash any of it's models, instead they just give them a coat of varnish/sealer (either purity sealer or Plastikote clear sealer) before applying the undercoat.

that's interesting,  did the forgeworld staff tell you that RuneBrush?

So they use a clear medium as a primercoat...interesting.

[RuneBrush]

Not directly but a couple of friends have been.  I've done this on a few resin models myself and not had any issues, so seems pretty solid

[Tommy]

Seems like a good place to ask whether anyone has tried something like this as a quick way to use primers for "shading"?

1 - Prime in black

2 - Spray white on top from one direction only (e.g. top down) hopefully resulting in some kind of gradient to black at the white "edges"

3 - A final full, but thin, coat of red (or any other of the colours in the range)

Hoping the red will be "transparent" enough for the top coat to appear lighter from the direction the white was sprayed on...

I know air brushes are the best way to do this, but ideally looking for a cheaper route to a reasonable tabletop standard!

 

[Kaleb Daark]

7 minutes ago, Tommy said:

Seems like a good place to ask whether anyone has tried something like this as a quick way to use primers for "shading"?

1 - Prime in black

2 - Spray white on top from one direction only (e.g. top down) hopefully resulting in some kind of gradient to black at the white "edges"

3 - A final full, but thin, coat of red (or any other of the colours in the range)

Hoping the red will be "transparent" enough for the top coat to appear lighter from the direction the white was sprayed on...

I know air brushes are the best way to do this, but ideally looking for a cheaper route to a reasonable tabletop standard!

 

no reason why zenith shading wouldn't work out of a rattle can, the result won't be as fine as an airbrush but no harm in giving it a try on an old mini.

[CoffeeGrunt]

You typically have to use Glazes or at least Layer paints to make use of it. Sadly GW Base paints cover over the effect for the most part and render it somewhat irrelevant.

Works nicely for quickie paintjobs though.

[Tommy]

I'm all about the quickie paintjobs where I can get away with them!