White haze from Isopropyl alcohol

[mjs101]

I've seen a suggestion to mix pigments in Isopropyl alcohol to get a good, powered/dust look. The alcohol gases off quickly leaving a comparatively stable pigment in a nice fine dusting. It worked great, and did a decent job of fixing the pigments in place.

However, one of the models I used got a bit of white haze on it from the Isopropyl alcohol:

View attachment 25624

Here you can see a successful pigmenting the model on the left and an unexpected haze from the model on the right.

What might cause this? Does anyone have any suggestions for removing it or avoid it in the future?

I did both models last night using to the best of my recollection, about the same amount of alcohol. The models themselves were probably painted at different times and might have had different varnishes (but both were probably touched last with Testors Dullcote.)

(I've googled and got a few hits about haze from Isopropyl on plastic, but mostly regard clear plastics and trying to clean car tail lights.)

 

[Demihuman]

I think, the paint is in an emulsion and the alcohol broke that. So the components of the paint separated and you got a mess. I think it actually looks kind of cool. Maybe this truck got to close to a fire? If you dont like it dont use the alcohol i guess, or add some water with your alcohol. Have you checked out weathering pigments? might be a good fit for you.

 

[mjs101]

I was using weather pigments (MIG), mixed with the alcohol. The alcohol settles like wash into recesses but then evaporates away leaving pigments fixed in place. I've struggled with pigments; they never seem to stick unless I mix them into a mud mix with matt or gloss varnish. This was my most successful pigment use to get a dusty effect instead of dried mud. I really like the left truck, but before I go weather 30 more tanks and half-tracks, i want to get rid of that white haze.

I think I'll try just water maybe with a bit of windex as a flow aid and just let it try overnight to avoid that haze.

 

[Demihuman]

I was using weather pigments (MIG), mixed with the alcohol. The alcohol settles like wash into recesses but then evaporates away leaving pigments fixed in place. I've struggled with pigments; they never seem to stick unless I mix them into a mud mix with matt or gloss varnish. This was my most successful pigment use to get a dusty effect instead of dried mud. I really like the left truck, but before I go weather 30 more tanks and half-tracks, i want to get rid of that white haze.

I think I'll try just water maybe with a bit of windex as a flow aid and just let it try overnight to avoid that haze.

Oh thats a different story. I have the same issue with the weathering pigments: nothing or way too much. I have no idea whats causing the white haze. I do like it but I understand you dont want everything to look like that. It might be your sealer going on too think. sometimes it 'frosts' if you apply it too quickly? Sorry, wish i was more help. Maybe some test runs on sprue or cardboard?

 

[RuneBrush]

It does look like something has reacted to the alcohol. Isoprop is really quite viscous and will loosen the bonding agent of acrylic paint quite easily (it's how you remove spilled paint from fabric).

Whenever I've done this, I've applied a coat of satin (or preferably Krylon Crystal Clear gloss) before the pigments - importantly from a spray can. These are lacquer based so shouldn't react to the alcohol providing you don't pour it on. The second vehicle looks like it just didn't have enough protection prior to having the pigments added. You should be able to brush them off with a soft toothbrush, varnish and reapply

 

[dontcallmefrancis]

You're capturing moisture. When you apply the alcohol/pigment wash you are melting the surface of what ever last coat you have applied to your finish. The alcohol may off-gas quick enough, but the humidity in your general environment may not. Thus "blushing" or the capture of air in your finish.

 

[mjs101]

So alcohol partially dissolves the previous surface? Whether it is capturing moisture or damaging the previous surface, alcohol is just too aggressive.

I've tied a few things.

Glaze medium + Alcohol. This was TERRIBLE. Two together created an opaque white layer. Into the simple green went that model! I thinke the alcohol interacted poorly with the glaze medium.

Water + a bit of windex + a little pigment. This made a wash that gave dusty look. I'd have expected to wash right off, but it is fairly resilient. Takes 6-12 hours to dry.

Glaze medium and Vallejo pigment medium. Start by pre-soating the model in the medium, and then mix in medium+pigment (very dilute), and washing over the area. Like a wash, this will settle into the recesse to make them show and accumulation of dust. This might take 36 hours for the medium to completely dry.


Glaze or Vallejo pigment medium + a lot more pigment. This is a much thick ratio, a paste. This forms dried mud.

Gloss medium + a lot of pigment. Wed mud. Might need an extra coat of gloss once dry to get the wet look. This can be a bit clumpy, like bits of mud.

 

[Demihuman]

In my airbrush I use 1 part alcohol to ~10 parts water. so maybe just diluting the alcohol might be the answer.