How to varnish for oil-paint weathering?

The Blue Sprue

Hi all - I'm returning to modelling after a short 30-year break. YouTube is blowing my mind - so many inspiring model videos.

My question relates to varnishes. I would like to weather my (aircraft) models with oil paints and oil/spirit washes. Some of the videos say you need a matt finish to apply oils to. Other videos say you should apply a gloss varnish before weathering because decals adhere better to shiny surfaces. I think it makes sense to apply the decals before weathering.

So... what's the order of application?! Should I do a gloss varnish first, apply the decals, then cover everything with a matt varnish before weathering with oils? Or should I apply the oil weathering direct to my un-varnished matt model, THEN put on gloss varnish, add decals, then finish with matt varnish at the end? I'm so confused...

Any help would be most welcome! Thanks :)

 

Hi Blue Sprue,

Of course, it depends on what you're modeling and what end result you want to see.

Typically, you want to clear coat and then apply decals to prevent silvering. I seal decals under another gloss coat and then apply washes and pin washes. Then comes the semigloss or flat coat. After that, I'll apply filters, dot filters, other washes for oil stains, weathering, etc., etc., and then seal that under another flat. 

We deal with these sorts of questions all the time in FineScale Modeler magazine. Here's a link to our Scale Model Basics videos. You'll probably also fine our Snapshots useful, too. And if you want more how-to, you can always pick up copies of FSM at your local retailer or subscribe.

Hope this helps.

Thank you so much! Wow - so that's a total of 4 clear coats. Two gloss and two matt. Do the clear varnishes need to alternate from acrylic to lacquer and back again in order to not react with the underlying layer?

Decals need a smooth surface to properly adhere. And oil washes for panel lines need a smooth surface because it eases removing excess. For washes in general, though, a dull coat is necessary. An oil wash on gloss just beads up on the surface like water in my experience. It's different for panel lines, because you're dealing with a concentrated amount in a very small area.

Typically, I do the gloss coat for decals, and everything after is dull coats. For me, it's more about sealing my work at each stage. Think of it that way. After decals, if I'm doing panel lines, I'll do them before I seal up the decals. But this depends on what I'm actually using for the panel lines. If oil wash or cheap poster paint, I'll do this right after decals because these are easier to work with (and wipe away) against gloss. Because dull coat/ flat paint is bumpy, it's hard to wipe away excess wash or panel line treatment. But if you're using a pencil for panel lines (light colored/lightly used planes like old hi-viz navy), you need to have a dull surface for the lead to work on.

I seal this with a dull coat, then go about washes and weathering, sealing each major application separately to prevent marring/ removing previous work. Sometimes it's not a complete coat, but one area. One thing I seriously recommend (don't worry, it's cheap) is to keep a paint mule around. A cheap kit, something that fell by the wayside, whatever, just something to experiment with. That way you can get a technique down, see how a certain paint or material sprays or dries, test compatibility if you have doubts about something. Hope this helps.

One more thing-I don't recommend applying washes directly to the painted surface before varnish, you might damage your paint. Let the varnish take one for the team if it gets too hot, better that than your paint-especially paint you had to mix! Don't mean to get all Columbo on you with one more thing, but I wanted to answer your question on that. Sometimes my fingers are faster than my brain- a problem here, but an even worse on on my models sometimes!

The sequence of types of clears used depends on the coat under it. Starting with your base color coat . If you dust on a clear lacquer lightly, really one coat will do and that will dry semigloss. So neither flat nor full gloss but decals and washes go well to it ( this is assuming airbrushing, if you're rattle canning the clear thats another matter all together). You can use that over lacquer in that light coat application if the base color is dry. It will go over base coat acrylic, I personally avoid putting lacquer over enamel though. For enamel color coats I use a semigloss acrylic for my clear to decal or wash to personally, that I mix up from flat and gloss thus have control over how flat or glossy I want my finish to be.

The final flat coat is up in the air from here but acrylic is most likely to go over most anything. Depending on the product line, for instance Krylon clear acrylic is fairly hot stuff and stinks ( last I knew anyway since I haven't used it in years). I use Liquitex varnishes and mediums for flats fairly often. Or lacquer where applicable. Tamiya clear acrylics or Vallejo are pretty mild, in the case of Vallejo very mild.

There are times I use a wash directly to acrylic paint. This is mostly replicating grime and deterioration on old automotive engines and engine compartments. I use acrylics on these 100% of the time for the color coat and often mixed craft paints. And I have water clean up oil stains I make my rust and dirty oil stain washes from. Works out fine. And mostly I don't use a final clear either. I want the raw grime look. Great in a military Jeep too just for some oil line seepage or even just for contrast. You would be amazed how much more realistic an engine looks just with a dark very loose watery stain applied for contrast. It gives dimension.

Omni Yomni

One more thing-I don't recommend applying washes directly to the painted surface before varnish, you might damage your paint. Let the varnish take one for the team if it gets too hot, better that than your paint-especially paint you had to mix! Don't mean to get all Columbo on you with one more thing, but I wanted to answer your question on that. Sometimes my fingers are faster than my brain- a problem here, but an even worse on on my models sometimes!

 

Thank you this is all invaluable feedback! I will be trying a new sequence in the next couple of days.

Thanks oldermodelguy these are great thoughts. I think I have a lot of experimenting to do :)