Seeking advice on weathering

[billmart]

I am in the midst of conducting some weathering experiments to see what works for me, and to gain some experience before moving on to a real model.  A couple of days ago I tried a Vallejo acrylic wash and an AK Interactive enamel wash over a base of flat ModelMaster paint.  I remember reading something by Marc R. that said don't use washes on flat finishes.  Now I see the wisdom of his words!

So, since I have several models that have been painted with flat paints (mostly ModelMaster, Krylon, RustOleum, or Duplicolor),  I want some advice on what to spray on them to get a gloss finish so I can then use washes.

Bill Martinsen
Rank Amateur

[marc_reusser]

Bill, I am ot in the field today....I will post my two cents worth when I get back this pm. Gloss os not necessary....there are many small nuances and points to be aware of...not the least of which is the materials you ar mixing/using.

[marc_reusser]

Bill,

You can use/do washes over a matte base, I frequently/typically do.....it is however not advised, and can make the wash or filter much  more difficult to control and work with, as the W&F will leech/seep into the "pores" (potentially making it look "speckled") and spread (wick) on the matte surface, making hard to control..and almost impossible to "work" or remove without leaving stains/traces on the surface.

Acrylic washes are also more complicated and tricky to work with than oils, as they do not have a lot of "working time".....they dry fast, and once dry...that's pretty much it (there are ways to deal with this such as adding a retarder,...and some tricks you can use to touch-up/repair small areas.) The benefit of the Acrylic though is that it dries dead flat...which is great for rust and dust.

Oils paints inherently allow for much greater working time and control...you can often come back hours or a day later and still work them to some degree. When talking about oils, you also need to differentiate, between "Artists Oils" , Humbrol (or other white spirit thinned hobby paints) and specially mixed/premixed weathering products such as  dust washes and  streaking-components. The  latter all are generally made (or certain ones in the line are) to be matte, however, the artists oils are a bit more tricky, because they generally use linseed oil as a binder/carrier for the pigment...the linseed oil is what can cause a sheen to the paint when applied. Some paints are worse than others (my personal preference are the ABT-502 Oils)....however, this can be somewhat mitigated/eliminated, by placing a small amount of the paint colour(s) that you will be using on a piece of 'Chip Board' (other cardboard works also..I just have a pref. for Chip Board)....let this sit for about 15 mins before using the paint, and this will then wick some of that excess linseed oil out of the paint. (you will notice with some experience/experimenting that there is a Sweet spot for this...where the paint still spreads and flows well without a lot of pigment speckling/separation when applied, and between when it does begins to do so.)

[In my own builds, when I work over matte paint, I frequently apply oil based filters over the paint as a first step...this gives me a slightly satin/"eggshell" surface. (after a week or so of drying)I will then often follow this with some panel shading/fading, or otherwise colour adjustments or additional modulation using oil based paint...this further slightly enhances the satin surface....this satin finish then later on allows the pin washes to flow like I want them to.]

Many of the modellers that I know like to use a satin finish (be it the paint itself, or a clear coat) to applly oil washes and filters over. This satin surface allows the washes to flow and be better controlled (and touched-up) as needed.

One thing that does concern me when I read your post/approach, is the use of oil based effects (washes/filter, etc) over an oil based base coat/color...this is pretty much a no-no.

The very basic/general rule of thumb in this is to, work opposite materials/finishes over each other. For example:

Acrylic Base > Acrylic or Oil Based washes/filters
Acrylic Base > Acrylic Clear > Acrylic or Oil Based washes/filters
Acrylic Base > Oil Based Clear > Acrylic washes/filters

Oil Base > Acrylic washes/filters
Oil Base > Acrylic Sealer > Oil Based washes/filters
Oil Base > Oil Clear > Acrylic washes/filters

..not all these are options I would use...and they can get more complex when you start to do special weathering effects such as HS chipping....but it is the general concept/approach.

You want the sealer to protect/encapsulate the material/paint below. As long as you obtain full coverage of the area/surface/piece that you spray it will be "sealed". The important thing is the full coverage, and choosing the proper material/paint for this that will work with the material/paint you are sealing, and will work with any subsequent material/paint you apply over it.

Note also that some of these paints that you are using/mentioned are not "hobby paints" and they may have chemicals in them, or drying time/out-gassing issues, etc., that do not react well with certain hobby paints you may apply over them. They may also not allow for certain hobby paints to properly bind with them when applied over....thus causing lifting/peeling down the line....so make sure you experiment with them first.

Insofar as what to use for a satin varnish over your oil based paints,...It needs to be an acrylic based one...but which mfr./brand is a personal choice. I personally have been using the Vallejo "Satin" clear, or if I feel daring, Tamiya 'flat clear', with some 'gloss clear' added. Both of these will need to be Airbrushed though, as they do not come in cans.

HTH,

M

[marc_reusser]

Chuck Doan uses a whole different approach to his washes/weathering by using Guache and thus eliminating the oil-on-oil problem. Guache is lovely and it dries dead flat..and can easily be re-worked.....but, you need to make sure to seal between applications (I think Chuck uses "Dullcoat"), as it is easily re-activated by a damp brush.

Marc

[Gordon Ferguson]

Bill,

just to add my own little comments to this ........... I am only about 2 small steps ahead of you in weathering experience but I am a great fan of the Artists Gouache
paints as mentioned by Marc and used by Chuck.

They are forgiving can be played around with and modified when dried with a damp brush and if all else fails you wash off and start again with no ill effects. When happy with effect you can seal with Dullcoat and move on to next step.

I thin them with water and a touch of Isopropyl alcohol just to break the surface tension ........... you could just use premixed screen-wash the blue/green stain in the screen wash will have no effect on your colours.

This was the method I used on the 7/8ths critter in last years Swap http://www.finescalerr.com/smf/index.php?topic=1267.msg22047#msg22047

 

[marc_reusser]

Bill;
Always be careful with adding alchohol or washer fluid to H2O when working over Acrylics, as they can cause surface/paint discoloration, softening of the paint, and cause the paint to take on a satin finish because of the chemical interaction. They can also cause rings/edges at the wet areas. You might be better off with a drop of "photo-flow" or sim product made for artists paints.

Gordon;
Nice to see apic of that logo again.

Marc

[billmart]

Marc and Gordon - Thanks for the advice and tips.  I now have some ideas on what sorts of experiments I ought to try.  I know much of the weathering process is personal, i.e., what works for one person doesn't necessarily work well for someone else.  I'm going to try lots of techniques to see what works best for me.  If I ever get the point of having something to show, I'll post it on this site.

Thanks again Marc and Gordon for your time and expertise.

Bill Martinsen
Rank Amateur, currently on a steep learning curve!

[David Emery]

I got the DVD "AFV Acrylic Techniques" by Mig Jiminez (from AK-Interactive's website).  That's an excellent introduction to a bunch of good techniques, and $20 -very well spent-  (http://www.ak-interactive-usa.com/product-dvd-vallejo.html )  No connection, other than a very happy customer/viewer.

Gouache paints are a lot of fun to work with and very forgiving.  I got a starter set from "Michaels" craft store with one of their 40% off coupon, and then bought some more colors at an art supply store.  (These were more expensive than the starter set, but worth it.)

Another good DVD is the Dave Revelia "Painting Detail Castings" from Scotty Mason:  http://scottymason.com/dvd/8/index.html  Last night I tried his 'unrusted metal' technique (silver stencil paint and pigments) and it worked great!

dave

[Chuck Doan]

Always thanks to Marc for great info.

I intend to try more oil based techniques. I first heard about gouache at the (defunct) Model trains weathered site. Its complete forgiveness as mentioned by Gordon is its strong point for me.