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Painting
Discuss all areas of historical miniature painting and painting preparation.
Thinning Humbrol for brush painting?
zemzero
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Ohio, United States
Joined: May 28, 2005
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Posted: Thursday, February 16, 2012 - 07:39 PM UTC
I use mineral spirits but it doesn't seem to work that well when I use a brush.

I usually thin a base coat to the "right" consistency, not too thin, not too thick. My highlights and shadows, though, get thinner and thinner, which means more thinner to paint ratio.

When I put a base coat down I usually wait a day or two for it to dry. When I come back to put a second coat on, it will strip away the first coat almost instantly. The first coat comes off so easily, it's as if it never dried in the first place. Even though it obviously is dry and the paint ratio has more paint than thinner to it. Why is the little amount of thinner completely removing the previous layer?

Are mineral spirits too strong to use when using a brush? Do I need to wait more than two days for each coat to dry/cure?

And this might be a silly question, has anyone ever used a wet pallet with enamels? I'm sure the fumes would be horrible, but is it technically possible?
Maki
Staff MemberSenior Editor
ARMORAMA
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Croatia Hrvatska
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Posted: Thursday, February 16, 2012 - 07:53 PM UTC
I usually brush Humbrols using Humbrol thinner, but I found mineral spirits work fairly well too. I'm not quite sure where the problem is... are you working on resin or plastic? Did you wash the figure before in soapy water, primed it perhaps? From what you wrote it seems to me like the paint does not stick well to the figure.

I too usually paint using very thin layers and never had similar problems. So I suspect it is the prepping the figure that could be an issue here.

Mario
endrju007
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Wojewodztwo Podkarpackie, Poland
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Posted: Thursday, February 16, 2012 - 08:01 PM UTC
I used Humbrol thinner which is dedicated for these paints - it worked well...
What kind of primer are you using? I think that most important thing is to have primer not reacting with the thinner.
Time you wait before second layer should not cause this kind of problems - I painted multiple layers with less than 6 hours between them and they did not strip.
zemzero
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Ohio, United States
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Posted: Thursday, February 16, 2012 - 08:57 PM UTC
They are plastic models. I've used Testors primer and lately a lot of automotive primer. I've had the primer be stripped off too when applying a second coat. I've actually just started a Greek figure that I primed with Humbrols primer, I didn't start painting it though. So I'll see how that works.

I also wash down the figures with window wash (Windex) and wipe off with a paper towel or use my airbrush to blow out any water from cracks or crevices.

It doesn't happen all the time, but enough to be a pain in the ass. I also notice that the paint separates from the mineral spirits fairly fast causing me have to stir it back up quite a lot.
endrju007
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Wojewodztwo Podkarpackie, Poland
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Posted: Thursday, February 16, 2012 - 09:29 PM UTC
Strange thing... the only time my Humbrol bubbled on the model was after using very strong decals softener... I never used mineral spirits with these paints, so maybe it's the problem of thinner. I have no idea...
Jon334
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England - East Anglia, United Kingdom
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Posted: Friday, February 17, 2012 - 12:35 AM UTC
I generaly use Humbrol thinners or W&N sansodor over Tamiya and automotive primers and I've never had any ill effects. Although I've not encountered any problems on figures I have had the odd instance of mineral spirits lifting paint on groundwork.
Deepgroove
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Texas, United States
Joined: May 28, 2006
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Posted: Wednesday, February 22, 2012 - 12:54 PM UTC
I've used Humbrol enamels to paint models of varying types, then figures, for over 25 years. Here's what works for me....
I wash resin figures before painting, but not plastic and metal. I also never primed a piece before painting. Never needed to. For thinning I've always had success with ordinary Testors #1156 brush cleaner/thinner. I use pallet paper (kinda waxy on the surface so the paint won't soak in) to work my paint prior to applying. Like you I give it at least a full day to cure before attempting a second coat or my shading. Mineral spirits are pretty strong, and will certainly attack the base coat even if cured for days. I found out through experience. My method is generally to apply my basecoats of colors one day, shadows the next and wrap up with highlights. It takes a bit of time but I've always had success with this procedure. Best of luck.

Randy
screamingeagle
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Connecticut, United States
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Posted: Wednesday, February 22, 2012 - 04:42 PM UTC
Hi Eric. Even though there shouldn't be a problem, there is something gone wrong here. Like the other gent's have stated, I too have used the same method without a problem but there are no guarantee's either.
#1. Even though you allowed 48 hrs, the paint may seem dry on the surface but sometimes the addition of the store brand thinner plus Humbrol's own solvent remains soluble under the surface leaving your first coat not 100% cured.
#2 Try a less volitaile thinner like Testors Brush Cleaner/Thinner as Randy suggested,(this thinner is also the best I have found to use for enamel and oils washes).
#3 Use Humbrols own brand of thinner as Mario mentioned.
#4 Or try again using the Mineral Spirits but add another day or two between coats.