Bubbles when painting

[sbarnby71]

I'm by no means new to painting (I started on Space Marines when I was 17, some 33 years ago), but over the past few years I've had this issue mostly when I'm basecoating, I get bubbles in my paint.  I use GW Grey Seer with a either pure sable or Kolinsky brushes and filtered water, but as I flick the brush backwards and forwards (I've watched Duncan Rhodes basecoat this way) I get bubbles appear and most of them pop, but some don't and I get an uneven coat.

 

For a while I thought it might be the way I clean my brushes, once I'd done for the day they get cleaned in either dish washing liquid or hand wash liquid, depending which sink is closest. So I thought maybe there is still some residue liquid in the brush, so I make sure they are run under clean water for ages after and I then re-shape the tip in my mouth, so I'd taste it if there was soap left on the brush.

 

I don't basecoat this way often as I tend to do batches with my airbrush, but now and again I need 1 or 2 bits that don't warrant the setup and cleaning time of the airbrush.

 

Any ideas, is it the flicking motion of the painting that does it?

[Lucien Eilam]

I’m not sure there’s a hard and fast rule, but I associate air bubbles with some combination of having the brush loaded with too much paint, trying to cover large areas too quickly, and maybe having thinned the paint too far, particularly over areas of detail where there are places for the paint to puddle. Essentially agitating pools of thinned paint.

 

So, slowing down a bit and carrying less paint on the brush generally solves it for me.

[sbarnby71]

I’m not sure there’s a hard and fast rule, but I associate air bubbles with some combination of having the brush loaded with too much paint, trying to cover large areas too quickly, and maybe having thinned the paint too far, particularly over areas of detail where there are places for the paint to puddle. Essentially agitating pools of thinned paint.

 

So, slowing down a bit and carrying less paint on the brush generally solves it for me.

Maybe it is the over thinning as I tend to use a small brush for base coating, a 0 which I know is too small for the task, but I just work better with small brushes and I don't tend to overload the brush as I'm very aware that I'm constantly having to reload the brush after just a couple of strokes and a bigger brush would be better.

[Grotsmasha]

I experience this with over-thinned paint too, usually my whites and lighter colours.

[Arkhanist]

Bubbles is usually a combination of thin paint and agitation. Shaking the pot a lot can lead to bubbles if you've thinned it inside, or aggressive brush action. Sounds like the latter from your description. Paints with a lot of titanium dioxide (white) suffer from it most.

 

Thicker paint, or a slower brush action should reduce the problem. A bigger brush (with a good tip) will help, as it carries more paint so you can 'flow' it on more rather than scrub the brush back and forth so much. Doesn't have to be Kolinsky though, if anything base coat brushes tend to take a bit of a beating so a more robust and stiffer sable mix is arguably better. Duncan uses an army painter Regiment brush for base coating IIRC, which is an affordable sable/synthetic mix brush that's roughly a size 2, which has an excellent reputation for the job. (I also use one for that job because the triangular handle gives me less hand cramp!). I keep my kolinsky's for detailing or blending. They all get cleaned with bog standard Masters brush cleaner, then a rinse in filtered water.

 

 

FWIW, I thin most paints with water+ instead of water - particularly for lighter colours (such as grey seer), it evens the pigment out and helps it cover more evenly, instead of going on chunky or with a larger pigment dump at the end of the stroke, but is otherwise very like water when it comes to consistency. I don't think I've had bubbles since I started using it either.

[sbarnby71]

Bubbles is usually a combination of thin paint and agitation. Shaking the pot a lot can lead to bubbles if you've thinned it inside, or aggressive brush action. Sounds like the latter from your description. Paints with a lot of titanium dioxide (white) suffer from it most.

 

Thicker paint, or a slower brush action should reduce the problem. A bigger brush (with a good tip) will help, as it carries more paint so you can 'flow' it on more rather than scrub the brush back and forth so much. Doesn't have to be Kolinsky though, if anything base coat brushes tend to take a bit of a beating so a more robust and stiffer sable mix is arguably better. Duncan uses an army painter Regiment brush for base coating IIRC, which is an affordable sable/synthetic mix brush that's roughly a size 2, which has an excellent reputation for the job. (I also use one for that job because the triangular handle gives me less hand cramp!). I keep my kolinsky's for detailing or blending. They all get cleaned with bog standard Masters brush cleaner, then a rinse in filtered water.

 

 

FWIW, I thin most paints with water+ instead of water - particularly for lighter colours (such as grey seer), it evens the pigment out and helps it cover more evenly, instead of going on chunky or with a larger pigment dump at the end of the stroke, but is otherwise very like water when it comes to consistency. I don't think I've had bubbles since I started using it either.

I do use a mix of 1 part Vallejo Matt Medium + 6 (or more) parts filtered water if I'm working with lighter colours, especially if I'm using a layer paint, but I find it a bit too dense for base-coating.  I think I'll give the Water+ a go and also try and slow my painting down with a bigger brush

[andes]

I agree with all of the above, plus I've seen it happen when I don't sufficient load the belly of a dry brush (as in, a not-wet brush not a brush used for drybrushing) and little bubbles emerge while painting. I get around this by wetting a dry brush fully in water before unloading it into some paper towel; then I load with paint.

Edited May 20, 2021 by andes

[Arkhanist]

I agree with all of the above, plus I've seen it happen when I don't sufficient load the belly of a dry brush (as in, a not-wet brush not a brush used for drybrushing) and little bubbles emerge while painting. I get around this by wetting a dry brush fully in water before unloading it into some paper towel; then I load with paint.

 

Huh. I *always* dip and blot a fresh brush in water before use. A habit I picked up from living in very hard-water areas, as the bristles would always dry quite hard and need wetting to regain flex. Until I eventually switched to Brita filtered water, and my brushes are now soft when dry. Didn't break the habit of a lifetime though.