Two separate questions:
Has anyone used Doc O’Brien’s Weathering Powders sold at Micromark or have an opinion of them? They seem like a good deal for what is included.
Second, can you apply an acrylic based wash over acrylic paints, properly cured, or do you have to alternate with enamels?
I’ve used doc obrien powders with very good results. Can’t help you with second question
The general rule when it comes to washes over paints is to alternate types…so if you have an acrylic base, you can use oil/enamel washes…if you have an enamel base, you can use acrylic washes, etc. Even though a paint finish is thoroughly cured, that doesn’t mean that a wash won’t lift the paint depending on the solvent used, how heavily its applied, etc. It’s not strictly necessary to seal a basecoat before doing washes but without it being sealed, your ability to adjust or work with it is going to be severely limited as a result. On unsealed surfaces you usually only get one pass/shot at whatever you’re going to do…and can’t apply it too heavily. HTH!
As mentioned, you need a “barrier” so the paint is not lifted by the wash. I don’t know about the powders you are asking about but MMP powders are great. They bite into flat paint and do not come off very easily as others do.
i paint armor and trucks with acrylics and wash with acrylics, artist oils, tamiya powders, pastel chalks, charcoal grill ash, real dirt, artist acrylics, real deal weathering paint (i have o’briens but haven’t tried it yet) and i have rarely put a barrier between my paint coat and my weathering and never had a problem. sometimes i may do a dulcoat if i have a lot of decals. I had only one problem with that. the dulcoat ran the tamIya sky blue on my SYRIAN POLICE BRDM which turned out pretty cool after i fixed it.
You can do this without a barrier if you are careful and do pin washes or an overall wash without touching up things too much. I usually do this on figures once the paint has set up for a few days to deepen the folds and shady areas but very lightly.
But if doing things like Dot filtering or successive washes then you do need a barrier or you are risking ruining the top coat from repeated applications. We all have our own methods and the best advise is to gather the info and methods described, and see what works best for you.
You DO NOT need a “barrier coat” when putting an acrylic wash over acrylic paint. Absolutely NOT. The acrylic will not harm acrylic paint at all. Putting down a barrier coat in this situation would only be wasting materials.
The only thing I would recommend would be to cut your wash with a small drop of dishwashing liquid to help it flow easier.
Agreed. Once an acrylic paint fully cures, it should no longer be water soluble. But, if your acrylic wash isn’t water-based, all bets are off. You just need to be cautious that the liquid solvent in the wash doesn’t dissolve your base coat. I recommend you always experiment on scrap before you apply to your model.
In my experiments, I found that a wash of Model Master Acryl thinned with Testors universal acrylic thinner will remove a Vallejo base coat. On the other hand, I found a fully cured base coat of Model Master Acryl is impervious to Tamiya’s X-20A acrylic thinner. I even vigorously scrubbed the paint with pure thinner, and the Acryl just wouldn’t budge. This is a surprises me because Tamiya’s thinner contains alcohols and other stuff, which I expected to dissolve the Acryl. So again, experimentation pays off.
You could also try a wash with a non-acrylic water-based paint, such as artist’s gouache. I haven’t tried it myself, but I know one modeler who swears by it. The thing about these gouaches is that the binder does not cure. So when it dries, it will still be water soluble. So in theory, you could undo a mistake with plain old water.
Chris
Doog
I don’t like using acrylic washes because they don’t flow the same as the solvent types. Good to know that acrylic washes behave different.
Hi,
Interesting thread - I do realize that these questions have probably been asked and answered before.
But to me this is very helpful right now since trying to finish my first evere KV-1 tank and it looks boring at the moment.
Have invested in some Tamiya Acrylics - there is not a lot else to chose from here.
Tried experimenting with some diluted (X-20A) XF-64 Red Brown over X-10 Gun Metallic for tracks and that worked out OK but no way near what you guys are achieving.
It looks like diluted red brown paint over polished steel, not like dust on cast metal.
But it did not lift the paint.
I have some oil paints and white spirit from before so i tried mixing a “wash”.
The result was only semi successful since this turns out glossy rather then dusty and faded.
Now I am thinking about using Humbrol enamels over the Tamiya Acrylics but I am pretty sure that the Acetone I used to use to dissolve the Humbrol colors is going to lift the acrylics as well.
Well - I will let you know when tested 
Artist Ink turned out glossy.
My wife’s concealer will also be tested shortly.
It is very interesting and also very funny - I am Happy Modelling
Starting to get a little nervous about health and safety though and will get goggles, respiratory protection and gloves. Is the dust from the pigments safe?
Zack
I apologize to Kolvir for this unfortunate Hijacking!
Two separate questions:
Has anyone used Doc O’Brien’s Weathering Powders sold at Micromark or have an opinion of them? They seem like a good deal for what is included.
Second, can you apply an acrylic based wash over acrylic paints, properly cured, or do you have to alternate with enamels
I am sorry -I will learn!
Zack
So basically I can’t use a wash with the same paint I painted it with, correct? I use Tamiya acrylics thinned with 91% alcohol. A wash of the same would ruin it all, or any other paint thinned with alcohol too?
Would a water based wash be fine then? If so what brands are water soluble?
Thanks for all of the posts. The last time I used washes it was with Games Workshop inks in the early 90s.
If you do your painting with Tamiya acrylic-lacquers you don’t even need to seal those when you do an enamel or oil wash over them. You’re MUCH better off to go with an oil-based wash, i.e., anything where you use regular mineral spirits to thin them. DO NOT use alcohol to wash–it is way too strong a solvent and will bleach many paints to a whitish fog.
If you’re going to do an acrylic wash, plain old water and a small drop of dishwashing liquid to cut the surface tension is all you need.
i will have to remember the alcohol whitish fog. may be an interesting technique for bleaching the top surfaces of desert vehicles to show really faded paint.
THANKS KARL for your help with oil washes. my BEDFORD PORTEE took a 2nd at regionals in softskins and the UN UNIMOG took a 1st in commercial trucks. both were weathered completely with artist oils.
I have used Doc O’Brien’s powders for years and have always had successful results. I have found that it should be applied over a flat finish as it won’t stick well on gloss. I never had any problem with it floating around in the air, but it wouldn’t be a bad idea to wear a filter mask when using it.
Same with spraying paints- I always wear a vapor respirator to keep it out of my lungs. You can get a good one from 3M for about $30 at the big box home supply stores.