White 'frosted' patches with diluted washes

[Eilief]

First post here after lurking for awhile, so hi all.

 

I'm having an issue when diluting washes and was hoping someone might recognise this problem. I can try to provide photos if need be but I've never taken any macro pictures before and only have a phone with the default lens, so I thought I'd try asking first.

 

Small patches of white appear in some of the recesses of a model after applying a diluted wash to the area. These patches look a bit like frost settled in a few of the nooks. 

 

The common denominator to each is the acrylic thinner medium that I use on all my paints/washes, Tamiya Color X-20A Thinner. 

 

This seems like the issue as I've tried with both washed and unwashed models, with a few different GW wash colours, and applying it to both metallic paints and non-metallics. The only thing I haven't tested is if it occurs on pewter or finecast/resin models, as I've only used plastic. 

 

I'm thinking I'll just switch to distilled water for washes while keeping the medium for paints. Any advise/discussion/information on any aspect of this would be appreciated if this rings a bell.

 

Thanks

 

Edit: spelling

[Dosjetka]

It sounds more like you're not shaking your pots of washes properly (if at all). Shake the heck out of them before painting and then shake them every so often while you're painting. I'm 100% sure but I think it has to do with the seperation of the various components in the paint which then leaves white patches/frosting when applied and dried.

 

Not directly related but it sounds like you're painting straight onto the models without undercoating them; is that right?

[Eilief]

Thanks for the quick reply. I do shake them but definitely not much. I'll give that a try and see if it helps.

 

These washes are being put on after cleaning (warm soapy water, rinsed off thoroughly and left to dry), priming (black) and base coating (a few thin layers of the base colour), if that helps.

[Dosjetka]

Glad to be of assistance. Oh, and welcome to the forum!

I also shake them for a couple of seconds or so and then end up regretting it when they start "frosting" (especially so with Vallejo washes, which really need an extra strong shake). Make it a habit to really give all of your pots, be they paint, washes, inks, etc a really good shake before each and every use.

A remedy for the "frosting" effect in this context is to simply take some brush-on matte varnish and put over the areas. Might take a few thin coats but it should definitely diminish the unwanted effect of badly shaken washes!

[Kaedes Nex]

One thing about the Tamiya X-20 thinner is that Tamiya acrylics don't work well if you thin with water, but work perfectly when you thin with Tamiya thinner.

 

This leads me to believe there's something in the Tamiya thinner that may be causing this effect with the wash. You will also see the frosting if you let the wash pool too thickly, thinned or unthinned. Thinning down the wash prevents pooling as the wash is thinner, but you may also be applying it more thickly than you would if it were unthinned, by virtue of it being thinner and less visible so you may unknowingly be applying more wash than normal, which would again lead to pooling and frosting.

 

And as mentioned, it's also an innate side effect of the formula if you don't shake well enough.

[Eilief]

Thanks for the advise guys, very helpful!

[disease]

dilute washes with their parent company thinner - e.g. for games workshop washes, thin with lahmian medium.  That usually stops the frost

[Atia]

Tamiya thinner is only for their paints and afaik alcool based if i remember it right. Dont use that for other paints/washes/enamels/oils

[ShinyRhino]

How old is your thinner?

I was getting this same issue using Winsor and Newton flow improver and Badab Black. Turns out the flow improver was old and I was getting a suspension of the chemicals in the fluid or something (W&N product support explained it better in their email). Bought a new bottle and it went away.