Painting Prep - A Discussion

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Painting Prep - A Discussion

Postby Zaggy » Mon Aug 26, 2013 12:00 am

Just thought I'd pose this topic for discussion, as in the last few months, I've been experimenting a bit with Primers and Surface Pre techniques, having become a fan of priming in Black - which is not as simple as I had actually hoped! Thus I am splitting this into three categories - Surface Primers, Painting Primers and Final Surface Prep. Not all three apply all the time, but being one of those 'adventurous types' (read; STUPID ;) ), who likes to go and graft DB603 noses onto a normally Jumo213 powered Fw 190D-9, in order to make himself a Fw 190D-15 (ie, three different plastics (two different kit plastics as well as plastic card), mutiple types of filler (CA glue, Milliput, Squadron Green, tamiya Liquid Surface Primer) including Alclad Primer/Microfiller and then a final Painting Prime), one tends to use all these steps; the same holds true when you start using lots of exterior Resin and Etched parts.

So, what I am going to do is just state my experiements, solutions, issues and questions, then see what we can all come up with!


Surface Primers - Primer/Microfiller

I discovered a LONG time ago that when using mixed materials, each with different surface characteristics, the best way to 'bring things together' was to use a relatively hard, Lacquer Primer Microfiller, that I could then polish with 1200-2000grit and better, to get a near consistent surface. While one still needs to etch primer or pre-sand etched metal, my favourite has generally been Alclad Black Primer & Microfiller. It not perfect - ie, can be temperamental if you get your shooting pressures wrong and or your surface isn't oil free, but i find that if the surface is either mixed media (ie lots of putty, different stuff) its my best bet.

I also used Tamiya Grey Surface Primer, but I tend to use this more as a liquid filler or really small seams or gouges or bubbles (in resin) or again over larger area's of putty. I also sometimes treat large area's of things like Squadron Green (which remains relatively porous, compared to plastic) with CA glue, to create a larger that is maybe 0.1mm thick of CA impregnanted putty - makes the surface much harder and polishes up a lot better. But beware - do this, and then have to sand back too deeply into the CA Layer, will result in some nasty tears the second you hit that softer putty layer again!

The main issue stemming from this step is that I have found that if I use Alclad Black, Painting primers, such as Modelmaster Grey Primer, just do not adhere properly to it - but we'll cover that next.


Painting Primers

This is the main area of recent experimentation, due to my growing appreciation for priming in black - and the main area of curiousity; I've yet to find a suitable regime, given my liking for Alclad Black Microfiller too! I use this part of the regime for two purposes; first and primarily it is a last chance check to make sure I havent missed anything and secondly, as something to gently polish in area's that are shown to be not perfectly finished.

Now, what have I tried:

- Vallejo Surface Primer - this stuff shoots an AMAZINGLY dense, smooth drying black colour; however it has the disadvantage of not sanding AT ALL! So if you shoot and find a minor gouge, you end up scripping huge area's of it. It doesnt sand, it just tears; both dry and wet sanding. Being totally not sandable, I'm not really sure what the point of this product is - unless you're happy with the surface and want a BEAUTIFUL satin black!

- Model Master Grey Primer - was told this stuff was the business, so I tried it; and being a fan of MM colour, I expected it to work! I bought NEW Primer, mixed it with NEW MM enamel thinner (where as with the colour I use the Lacquer thinner) and shot it - what a disaster! The area's that I misted a single thin coat, dried BEAUTIFULLY! Area's that I applied a second coat to, over touch-dry area's, ended up taking a month or so to dry - in front of a warm air blower! Now I conceed, I may have gone a bit heavy in places, but still, that drying time was ridiculous!

Not only that, but I soon discovered (well, soon after a month of drying) that ANYTHING that landed on Alclad black (both the heavier coats and the thin, single layer coats), didnt bite at all! The moment 1200grit touched it, the MM Grey Primer just came off in strips! To contrast this, anything that landed on plastic, sanded beautifully!

- Life Colour Acrylic Paint - way too soft to use as a primer; the stuff just doesnt key into plastic at all. Gunze Acrylics are much harder drying, but again, their paint and not really a primer!

- Alclad Gloss Black Primer - Temperamental to shoot (temperature, pressure, humidity), but probably the most sucessful to date; except for the fact its GLOSS! Looks incredible under Alclad Metal Lacquers though!

SO, any further suggestions? Ideally in Black. My current experiement is going to be to shoot Tamiya Enamel Black, but again this is going over alclad, plastic, etc; I am really hoping that the surface is prep'd enough to not require much in the way of extra finishing/sanding...


Final Surface Prep

This is with regards to prep'ing the surface for either the above stages or paint; to get rid of that pesky skin oil that alway seems to find its way onto the surface. My technique has usually been to give the thing a once over, then mask, then go again (unless I am able to only grab a hold of something already masked off). I've used:

- liquid detergent (very weak mixture in warm water) to wipe a model over with a damp cloth (not exactly the best way when you have a lot of masking) - I have found sometimes this can leave a detergent residue!

- metho - sprayed into a cloth and wiped over the model; not the best again, when dealing with masking, but probably better that the 'wetter' detergent method. I suspect this could be iffy over acrylics also

- medical alcohol wipes - pretty good for ease of use, but some brands will leave small amounts of lint if you catch them on antennae. And like the prior method, I suspect over acrylics, could be iffy.

- damp cloth - hard to go wrong with warm water, but has the disadvantage of not 100% removing oils! ALso, no ideal with masking!

Again, any further suggestions?
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Re: Painting Prep - A Discussion

Postby billb » Mon Aug 26, 2013 9:33 am

My 2c worth.
I generally fill (or coat something like milliput) with superglue to avoid a porous surface.
When I think I've got the construction done everything gets a good wipe over with metho to remove oil.

Black primer - Army painter spray black undercoat which I think is alacquer based acrylic. I spray straight from the can (warmed and well shaken) but you could also decant. Covers all types of material, is a fantastic microfiller and sands/buffs beautifully. Highly recommend this stuff. They also do a white and gun metal primer that I haven't tried (yet). Up until now I've used tamiya lacquer grey and white but it's not as good as the Army painter stuff. You can get Army Painter from War and Peace games on the net. http://Www.warandpeacegames.com.au
You can see it in use on my n/aw-10
I then do whatever final seam etc tidyup is needed, buff it with a cloth and paint from there. I do try to use cotton to holds out from that point on though.
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Re: Painting Prep - A Discussion

Postby billb » Mon Aug 26, 2013 9:45 am

Edit, the last sentence should day hold it with cotton gloves from that point on.
Long posts on a phone do not work
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Re: Painting Prep - A Discussion

Postby Zaggy » Tue Aug 27, 2013 1:10 am

@billb - yeah, phone's arent ideal to post on ;)

I also try to avoid any sort of contact once final painting begins - in the case of the WW2 Prop's that usually takes the form of a coat hanger, wrapped in tape (for a snug fit) through the prop shaft or if the whole radiator is off, a Taped-up, Rolled up Piece of A4 paper, (so there's a little bit of shock absorbing in there) connected to a piece of plastic pipe... Allows me to get the thing to almost any angle I need. Modern Jets tend to get something similar done up engine exhausts or wheel wells - at very worst, I sit the thing on blocks of high density foam on a turn table and paint the thing in stages (flipping with gloves)...

The trouble with all this is of course masking - cotton gloves always leave little bits of cotton in the masking, while tape always seems to stick better to latex gloves than plastic/paint ;)

Very curious about this primer of which you speak too! Sounds like it may tick all the boxes - can it be bought in a bottle or is it a spray can only deal?


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Re: Painting Prep - A Discussion

Postby billb » Thu Aug 29, 2013 9:50 pm

Holding the model is definitely the issue. Different for each model. I gave up on latex gloves as I managed to leave worse fingerprints with them than I did with bare fingers. Still got nfi how I did that.

With the primer I think it only comes in spray cans, but it actually works really well straight from the can as long as you don;t spray it on insanely thickly. Spray form 20-30cm's and keep the can moving. Even if it looks like you've got it a bit thick just let it dry and you'll be surprised.

You could also decant it if you wanted to and I think it would work nicely. Wouldn;t waste as much into the air either. Definitely worth a try though.
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