Capillary action in action

I mentioned capillary action earlier as a law of physics that pulls a liquid into small spaces. Just touch the tip of a small brush loaded with the wash or ink against a panel line and let the liquid do it's magic.

Here's an animated gif of it in action. It's taken at 10 frames per second.
I'm using Tamiya's "Panel line accent color" in dark brown.

Too much wash?

After successfully applying the dust wash to the rubber tracks, I wanted to try and give a slightly sandy/dusty look to the entire model.

I started on one of the vertical sides, but the fluid just falls to the bottom and pools up or falls off. To counter this, I tipped the tank on it's side, then re-applied the wash to the (now horizontal) side.

I may have overdone it and after the thinner had dried, it left circular stains, not exacty representing the look I wanted. So, I added a second layer, after tilting the model 45 degrees, and worked out the stains by repeatedly brushing accross them. The thinner in the solution picked up part of the stains, so it looked promising.

The result after 12 hours is "slightly" overdone and far from the subtle dust-effect I was aiming for.

Because I was told you can remove the wash up to 24 hours after applying it, as soon as I came home, I loaded a paintbrush with a small amount of White spirit and started (gently) rubbing.
I'm happy to say all the pigments dissolved again and were easily wiped off with a cloth. The clear coat of varnish has protected the underlying paint, so no damage is done. (Hence the importance of protecting your paint-job)

It's now 24 hours later and there's no layer of dust, but at least we've learned something, fixed a mistake and can start over.

Washes

Washes are used to put accents on certain parts of a model. Mostly it's used to accentuate (recessed) panel lines. By loading a paintbrush with a little of the solution, then touching the tip of the brush to the edge of a panel line, something called "capillary action" will draw the solution into the entire line.

(Capillary attraction: the ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to external forces like gravity)

I have two types of washes to try. 

One is the AK Interactive desert dust wash I used on the rubber tracks (see earlier post). This beautifully flows around all the details of whatever you're touching your paintbrush to. This one is dissolved in "White spirit" (also called "Mineral spirits", I believe).

The second is the Vallejo black wash, which is water based. I used it before to dirty up the floor of the Puma's interior. There's almost no capillary action happening here, it tries to stay together as a big drop. You really have to brush it where you want it.

I applied the black one on everything that looks like it might get dirty.

Left : applying the wash on all the details.
Right : removed excess fluid with a piece of cloth.

 

Why varnish?

Why is it important to put a layer of varnish (or clear, or gloss, or whatever name you want to give it) on your model?

A first layer after you've finished painting protects the paint by sealing it in airtight.

• It protects against moisture in the air and handling it with your hands.
• It enables you to add weathering with washes, inks or pigments without accidentally damaging the paint. More importantly, it enables you to remove excessive weathering, again without damaging the paint (more proof in my next post).
• It provides a smoother surface for placing decals. Decals adhere better to a smooth surface than a rough one. Unless your paint is glossy, you might have problems getting your decals to stick.

After applying decals, a second layer of varnish will protect those decals from silvering and make the edges of the clear film (on which the decals are printed) less noticable.

A rather large decal , easily placed on the first layer of varnish.

A second layer of varnish seals in the decal.

Dust wash

I tested the "African dust effect" wash on the vinyl tracks, because they are separate from the model and can be easily rinsed if it goes wrong.

The AK Interactive wash is super-fluid and capillary action works it's magic : just one touch with a paintbrush to the track and it flows perfectly in all the small crevices. The result looks good and even better on the assembled model.

The model itself is now drying after two layers of Alclad 2 semi-matt clear. When dry, I'll start applying this same wash to the entire surface.

Play- ... d'oh!

I used play-doh successfully to mask and airbrush difficult shapes, but you'd have to paint it right away after applying it. If you don't, 24 hours later it looks like this :

It's pretty much useless now. It's not really a problem since the pieces remove easily.

I tried again with modelling clay. The clay seems to dry slower and shrinks less, causing less or no cracks.
I didn't wait for it to dry though and sprayed the final color : insignia blue.

The letters are impossible to mask and will be done with a brush.

Trying new things and new brands

Because my experiments with Vallejo varnish (especially the glossy one) are far from good, I decided to get some info on other brands. I had to pick up new paint anyway and was hoping the storekeeper would have some experience, which - turns out - he had. This may seem logical, but some hobbyshops (especially the larger ones) have cashiers who know nothing.

• For the regular varnish, to protect the painted model, apply decals, then seal in those decals, he recommended Alclad 2 lacquer (semi-matt). It's not water-based, so you need a lacquer-thinner to clear your airbrush afterwards and it smells a lot more pungent than acrylic paint of course.
• He didn't have the glossy one in stock, but - since I''m experimenting with other brands - I took the Tamiya X-22. According to online references it takes weeks to dry and many people don't like it, but the trick seems to be to thin it heavily with lacquer thinner, even though it's not the logical choice.
  (I'll try it soon)
• I want the Abrams to look dusty, but not too much, so I enquired for that also and he suggested a wash from AK Interactive. They have a range washes and dry pigments, depending on how thick you want to create the effect.

From left to right, top to bottom : AK Interactive Africa dust effect (wash) + white spirit, Humbrol maskol (liquid masking, supposedly 10 times better than Vallejo's), Tamiya X-22 gloss clear, Alclad 2 semi-matt lacquer + Tamiya lacquer thinner and the reason I went to the shop in the first place : Olive drab and Insignia blue.

I've tested the Alclad lacquer right away on the Abrams and, at first sight, the results are very promising. I used it straight from the bottle, sprays nice and even. Extra bonus : no tip-dry. Slight disadvantage : the smell, so wear a mask and ventilate well.

I used it on the submarine as well. Pictures soon.

Brushing varnish

Because airbrushing gloss varnish is still a skill I can't yet call mastered, I tried brushing the varnish on, just in  those places where decals will go. The entire model will be coated matt, not glossy, but for best decal adhesion, a gloss coat is highly recommended.

I applied it to the two sloped panels, on both sides of the canon. The left side with unthinned varnish, the right side with 1:1 varnish and thinner.

The thinned version (right) smoothed itself out evenly, but you can still see it's brush-applied. The unthinned side (left) shows an uneven, pebbly surface. I'll redo the left side, then start placing decals.

First round of camouflage

The first camouflage colour ("Tank green") is applied to the Puma's turret and I removed the putty soon after.

If you look close, you can see the edges where the paint pulled up against the putty. Even though I was careful with applying the green paint, the consistency wasn't perfect and it went on too wet. I'll try gathering some tips to prevent this on the next IPMS meeting.

Overall, the result looks fine, even if it will require some clean-up work.

I removed the protective cover from the body, only to find the paint peeled off with it. The paint seems to stick harder to itself than to the model. Maybe the model wasn't sufficiently clean, or I should just be more careful. Won't happen again!

Transparent parts

Transparent parts have always been a little difficult to get right for me.

In the distant past, I painted them with normal paint, which totally ruined the transparency of course. 

Then I started painting them on the inside (still with normal paint), which kept the idea of transparency, but no more then that.

Ideally, I'd find a way to make it appear as if there's a lightsource behind the part, but that might be overreaching.

For now, I'm painting the inside with transparent paint, which exists in practically all paint brands. When dry, I will coat one with aluminum foil, just to see the difference with the other part.

(Yes, one of the parts is broken. This Enterprise is clearly cursed, but if you know the Enterprise C's story, that's no surprise)

Below is my test card for the transparent blue paint.

On the right side, I mixed 1:1 transparent blue with glaze medium. The result is rather pebbly.
On the left side, I mixed 1:1:1 transparent blue, matt varnish and thinner. This result is smoother. Not sure whether the varnish is better than the glaze or if the extra thinner did the trick. (Maybe I should start skipping steps during experiments and not change 2 variables at the same time.)