Chalk pastels over oil wash?

[TonyOD]

I'm a brush painter starting to make tentative steps into weathering. On my current build I put a coat of Klear over the enamel paints, then the decals, then another coat of Klear, then an enamel panel line wash, more Klear and then a "dot" oil wash, which has added a bit of something. If I wanted to do a bit of pastel weathering on this should I put another coat of Klear between the two, or will the pastel happily sit on the oils once fully dried?

cheers

Tony

[pigsty]

Chalk pastels will sit happily over anything - they're chemically inert, no solvents or nastiness left in them.  However, they find it hard to cling to a gloss surface.  You've got three coats of Klear (three!).  If your last wash went over all that without making fish-eyes or refusing to settle, you should be fine.  Otherwise, maybe matt it down a bit.  And as ever, find an inconspicuous spot to test it on first.

[Dr. Quack]

I agree - no problem applying pastel chalks over oil weathering.

If your top coat is Klear then it's probably quite glossy and the chalks may not adhere terribly well. A matt coat or even satin has a rougher surface so the powdered chalk grips better. The same applies to oils - a glossy base allows the oil wash to flow along panel lines and around moulded details, but a matt or satin varnish is better for stains and streaks.

Have fun with it and let us see how you get on.

Niall R

[TonyOD]

@pigsty @Dr. Quack - many thanks. The oil wash has matted it down a bit but it would probably benefit from a matt coat. I'm a little terrified of wrecking the build at this late stage so may practise on a scrapper first!

 

Cheers

 

Tony

[Troy Smith]

51 minutes ago, TonyOD said:

If I wanted to do a bit of pastel weathering on this should I put another coat of Klear between the two, or will the pastel happily sit on the oils once fully dried?

Chalk pastels will work better over over something with a bit of 'tooth' which is a matt coat.

I've mentioned before,  I think there is a lot to be said for a variation of sheens on a finished model,  chalk pastels are good for exhaust deposits which tend to be very matt and sooty,

the exhaust on this is paste chalk, my first go,  an dark grey base, and then some lighter grey stippled over,  I also use some light grey dust to try to show the lighter fabric areas,  which was not as succesful, you can see some chalk over the L1952 if you look. 

 

 

 

 

and for dried mud.

My method would be to get very fine abrasive and get some pastel dust, mix to a colour you like,  and then add some lighter fuel and dab on for exhaust deposit, or with more lighter fuel it goes on as a slurry. 

You can remove most of it with a brush damped in LF as well,  but you won't get the last off. 

does a good job of dust setting into crevices I find. 

you can  the dust on here, 

 

this before the oil wash and pastel chalk 

 

HTH

 

 

[TonyOD]

Well thus far I've found The @Troy Smith Method very reliable - used lighter fuel for my oil wash, super! And I had planned to stick exhaust/cannon/oil staining over the top of everything. We'll see how it goes.

[Troy Smith]

16 minutes ago, TonyOD said:

And I had planned to stick exhaust/cannon/oil staining over the top of everything. We'll see how it goes.

I'd suggest you idea of a practicing on a scrapper first is wise, it's what I do to get an idea of how it works.   

Just to note, I was trying to make the Jeep and truck look like they had a good coating of summer dust that had been rainwashed off at points as well in Normandy, aiming for chalky dust,  Normandy is part of the same band of chalk the South Downs is,  so I had an idea of what the dust should look like, the soil here in the summer dries out to a light grey with a very subtle brown purple hue...   I probably should have just used some real dust! 

 

In the case of you Spitfire, I'd go with the less is more approach,   photos of the model before and during can help here as give a different perspective to what on the bench.

 

HTH