Weathering using watercolor paint wash

[Capt. Kelso]

I have not had much success with acrylic paints, especially weathering. So, picked up a tip regarding using "watercolor paints", NOT "acrylic watercolor paint" for weathering and gave it a try. The advantage of using non acrylic is that it is easy to remove, just wipe off with a damp brush or cloth. Or wash it off and start over. And it's easy to drybrush over.

 

I used enamel paints for base colors and highlights. I think if you use acrylic base paint it will need to be sealed before adding a wash. Once the base color is dry, to weather, apply a wash (dark grey in this case), simply thin with water, I add a drop of detergent. Let dry. Trial and error to get the right look. I used the same process on the figures. Once happy with the look used a dry brush technique for the highlights.

[druxey]

Very effective and grungy!

[Keith Black]

 Very nice and very believable. 

[wefalck]

Indeed, a nice paint-job. I like these rough thick layers of paint on the inside of the boat, real workboat-like 👍🏻

 

Why do you say that acrylics would need to be 'sealed'?

 

The enamel paint surface would be slightly water-repellent, which is why you need the detergent. Acrylic paint surfaces are more hydrophilic, at least the satin and matt ones. You can work on them without detergent.

 

I actually used watercolours straight from my watercolour-painting box, the solid ones, but then I am working in small scales.

[Bob Cleek]

Beautiful work!

[Capt. Kelso]

wefalck, I was considering using Vallejo Acrylic for the figures and reviewed some of the plastic model forums for feedback. I did note some recommendations to seal the base coat before applying a wash and highlights. It appears this step helps protect the base coat from damage during the weathering process. I interpreted that to mean damage from dry brushing rather than the wash. This made sense to me as other sites noted acrylic paints are not as durable. 

 

I did try using an acrylic wash on one of the line tubs and found it difficult remove once it dried. 

 

 

[wefalck]

Acrylics seem to dry very fast, but in reality it can take days or weeks for them to fully harden. However, they are normally not as hard as the enamels, say Humbrol. So, if you anticipate to have to remove/correct any washes, this may be indeed an issue.

 

On the other hand, one element of the hardening process of acrylics is that residual water in between the crosslinking molecules is slowly diffusing out, so that would be prevented by varnish, particular if it is an enamel-based varnish and not an acrylic varnish.

 

Watercolour paints do not dry waterproof, so any attempts to apply more 'weathering' would dissolve the previously applied paint. Sometimes people call gouache also 'watercolour' because the solvent is water - in this case the paint dries upt more or less waterproof.

 

Personally, I got quite used to do washes with acrylics. You can build up layer upon layer quite quickly, so you can approach the desired effect gradually. Of course, if you don't like the effect in the end, that's not so good news. Having said that, I sometimes do apply intermediate layers of acrylic varnish to give me a bit more leeway, when I think I need to correct. Matt or satin acrylics have a slightly rough surface obviously and even fresh washes do not come off completely. Here the varnish helps.

 

Plastic- and figure-modellers these days seem to be quite fond of these intermediate or separating layers of varnish, but I think even when applied with an airbrush, there is a risk of flooding details or loosing crisp edges, so I rather try to avoid this.

[Thukydides]

The varnish layer is usually used to do one of two things:

1. A gloss layer to allow the washes to better flow (for example when you want to do panel lining). (I personally have never bothered with this as I found that if you let the paint dry fully then as long as you are careful with the oil wash, it is never a problem cleaning up spills).
2. To protect the layer beneath if you need to clean off overspill or are going to be rubbing it off in the case of say an oil wash.

For the everyday run of the mill base coat - wash - drybrush you don't need to seal the layers. There are also cases when you are doing a competition piece where you might want to have a save point you can revert to, but that is for models that you are putting hundreds of hours into painting.

 

I have painted hundreds of model figures, some to a fairly high standard and I have never sealed them except as a very last step to protect the paint job from handling and adjust the sheen. The only exception to this is I seal the area before applying decals.

Edited March 11 by Thukydides

[wefalck]

Also keep the old masters' rule in mind: fat over lean - meaning it is ok to apply oils or enamels (provided the solvents are compatible) over acrylics, but not the other way around. The old masters started off with egg-tempera and finished in oil. The reason is that 'lean' (or hydrophilic) paints do not stick very well or at all to 'fat' (or lipophilic) oils/enamels.

[Keith Black]

One instance where one might want to seal an acrylic finish before applying the next wash is the case of being almost satisfied but thinking maybe 'I might be able to do better', might being the key word. I don't how many times I wished I had left well enough alone but if it's sealed, you can try to make it perfect with multiple attempts.