Dullcote leaving white spots

[ulrikk]

I recently finished my first two miniatures. Since they are gaming figures I also had my first experiences with varnishing minis. At first everything went fine, I gave them a coat of gloss varnish which worked great. To kill the gloss look I then gave them a coat of thinned brush-on dullcote (1:1 dullcote:turpentine). At first everything looked fine, but as they dried up I found white spots had formed on the minis! It looked like the result of a wash where the spots had formed in the recesses of the figure. Fortunately it was just in ~10 places these spots had formed and I was able to dissolve then with pure turpentine on a brush. Unfortunately, if left to pool this mix then dries into another white spot. Right now I'm fighting the spots, trying to dissolve them with turp and then suck it away with a dry brush and tissues. It's working, but not too well.

 

Have you tried this or was I just unlucky? What did I do wrong? I suspect there was too little turpentine in the mix.

[herzogbrian]

I recently finished my first two miniatures. Since they are gaming figures I also had my first experiences with varnishing minis. At first everything went fine, I gave them a coat of gloss varnish which worked great. To kill the gloss look I then gave them a coat of thinned brush-on dullcote (1:1 dullcote:turpentine). At first everything looked fine, but as they dried up I found white spots had formed on the minis! It looked like the result of a wash where the spots had formed in the recesses of the figure. Fortunately it was just in ~10 places these spots had formed and I was able to dissolve then with pure turpentine on a brush. Unfortunately, if left to pool this mix then dries into another white spot. Right now I'm fighting the spots, trying to dissolve them with turp and then suck it away with a dry brush and tissues. It's working, but not too well.

 

Have you tried this or was I just unlucky? What did I do wrong? I suspect there was too little turpentine in the mix.

 

I have had Dullcote SPRAY cloud up on me before and have 'corrected' it by appling the spray again with perfect results.

 

Never used the liquid before. It could be your turpentine that is hosing your up. I may be wrong, but always thought that Dullcote would be better diluted with Lacquer Thinner which has different properties than turpentine. Also, the purity of turpentine can vary widely.

 

Cheers,

Brian

[ixminis]

From the sound of it, the wash was not completely dry, so the varnish gave white spots where the moisture was. try to duplicate it on a junk mini/a bottle cap or something. The only brush on varnish I've used is the Reaper brand and I haven't had that trouble (I've also learned to be doubly sure about washes being dry before sealing 'em... To me, the good news is that if it's in a dark and/or lined area all I have to do is place the shadow color to conceal the white spots)

[John Lee]

It could be that you are thinning it too much. The "dull" part of the dull coat is a fine suspension of particles in the "coat" part, that is why it is very important to shake the can/bottle very well. Prehaps when you diluted it with turpintine, the mix pooled in the recesses and caused the particles to rise to the top. Try brushing some straight on and see what happens ( use an old mini if you don't want to use a new one). Unless it is really, really thick, I wouldn't thin it at all.

 

 

John Lee

[eastman]

The bottled liquid is really intended to be thinned with lacquer thinner (white mineral spirits) and shot through an airbrush

[geaugan]

So there is no confusion. Dullcote and Glosscote are laxquer based. They should be thinned by lacquer thinner only. Unfortunately unless you buy their own thinner in a small bottle your only other choice is usually a gallon container. It is very dangerous stuff to mess with so don't strike a match or take a really deep breath. Those of us that used to frequent auto body shops in the 70's remember the smell well,

[Madog Barfog]

You don't specify which brand you use. That will help to determine with what or whether to thin it.

[tanker22]

I've only had an experience acouple times with the spay on Testors Dull coat were it did this and it was also becuase of a wash not being completly dry dry as mentioned above. Other than that I've had pretty good luck with it. Never tried the brush on lacqure before.

 

High humidity might be an issue as well in the drying? Not sure just, a thought

[Joe Kutz]

Humidity doesn't really cause much change in the drying of solvent based paints (it does...but not nearly as much as you have with acrylics). It will however mess with the way rattle cans behave (several different issues relating to the density of the air and the way pressurized gases react with it).

 

If you try to seal a mini that isn't quite dry and is painted with water based paints, you can get clouding of the clear coats due to the water trying to escape from the underlying paint and being trapped by the clear coat (think about breathing on a cold window...not quite the same but close enough). Make sure that your water based paints are fully dry before using a solvent based sealer on them. You will have fewer issues sealing a water based paint with a water based sealer or with a sealer that is actually water cured (several urethanes cure with exposure to moisture and actually require higher humidity to dry completely).

 

Most likely though you had an issue with brushing on a sealer that wasn't formulated for a brush. If it is in fact the Dullcote in a bottle, it is designed for use with an airbrush. The airbrushing process allows the thinner to dissipate much faster so you do not have the surface tension effect that you get when used with a brush (quite often it will be nearly fully dry within minutes with an airbrush). When you brush it on, the thinner and medium are in suspension. When there isn't an even drying rate (normally caused by different thicknesses in application...something that is normal with a brush) you have a situation where the receding liquid will actually pull the matting agent with it towards the thicker areas (quite often where you end a brush stroke). When it finally dries, these areas have a higher concentration of matting agent which will lead to spotting. You can have a similar problem when you over thin in which case the opposite effect will happen from time to time leaving small rings as opposed to small spots.

 

As far as thinning goes...turpentine will work as a thinner for most solvent based finishes, including lacquers. Lacquer thinner can be a better option - but normally I will default back to what I normally recommend. If a company produces a thinner for their products - use it. While you can use a generic turp or lacquer thinner and you might not have any problems...they are not all created equally. A lot of stuff that is called lacquer, isn't a lacquer in the traditional 1970s sense of the word. A lot of the thinners are not the same as well. In my shop I have 4 different cans of lacquer thinner for use with actual lacquers. They range from being as high as 60% toluene to having none at all in the new environmentally friendly crap. Depending on the actual makeup of the medium you want to thin - you need to have a solvent that is strong enough to handle it. The chemists at the paint companies should have handled that work when the lines are produced - if they get it wrong...you have a recourse to go back to. However if you use a strong thinner in a clear coat and it ends up melting the paint off your mini...you will not be too happy (had it happen...nearly melted the plastic mini itself too).

 

BTW - if we are in fact talking about Dullcote^TM as opposed to dullcote (as in generic term for matte finish), then it is designed to be thinned with a toluene based lacquer thinner. This is going to be changed sometime this summer though as the EU has banned the import of toluene and toluene based products. As a result Testors is reformulating several of it's lacquer based paints and finishes and moving them to a more friendly alcohol based finish. They however are not going to be changing the name. For people who use the paints that are being changed up keep an eye on things (and a nose). Lacquer thinner and alcohol are not interchangeable thinners.

[ulrikk]

Thanks for the replies, guys. Much appreciate it.

 

From the sound of it, the wash was not completely dry, so the varnish gave white spots where the moisture was.

No, it's the other way around. The minis that were affected the worst were painted four months ago, while the two that were affected the least was finished an hour before the dullcote. I'll post a picture (i.e. horror-shot) when my camera battery is charged.

 

It could be that you are thinning it too much. The "dull" part of the dull coat is a fine suspension of particles in the "coat" part, that is why it is very important to shake the can/bottle very well. Prehaps when you diluted it with turpintine, the mix pooled in the recesses and caused the particles to rise to the top. Try brushing some straight on and see what happens ( use an old mini if you don't want to use a new one). Unless it is really, really thick, I wouldn't thin it at all.

This makes a lot of sence, but I think all the people writing about dullcote have recommended thinning it down. The general idea was that a couple of light layers were better than one thick layer.

 

The bottled liquid is really intended to be thinned with lacquer thinner (white mineral spirits) and shot through an airbrush

I'm beginning to suspect that too. Unfortunately, it is being marketed as a brush-on sealer so in my naivety I brushed it on.

 

You don't specify which brand you use. That will help to determine with what or whether to thin it.

I'm using Model Master Dullcote. To the best of my knowledge it's the same product as Testors Dullcote.

[ulrikk]

This is the worst of the afflicted miniatures. That white residue just doesn't make african tribesmen look any better.

 

 

@ Joe Kutz: Thanks for the info. Guess I'll have to look for my ancient airbrush in my parents house. I'm still not quite sure what factor made it all go terribly wrong (brushing? Turpentine thinner? The gloss varnish under the dullcote? who knows... ) , but experimenting with the airbrush cannot hurt.

[dougrob173]

You could always base him in snowy terrain, this way it looks intentional

[Jubilee]

try spraying him with some kind of spray-on matte varnish before you give up entirely. Sometimes that takes care of those kinds of problems.

 

I've tried testor's brush-on dull cote and I don't like working with it. little particles dry instantly on my brush, and it's very hard to brush on smooth. And you have to do a heck of alot of shaking to get it mixed, and it settles almost instantly after you put it down.

 

/ali

[Joe Kutz]

That is definitely from pooling of the Dullcote. Unfortunately, a second coat will not do much except aggravate the removal of the concentrated matting agent. You might try using a brush wet with thinner and pull it away from the recesses where it gathered into the more open areas. It should help to spread things out a bit and by ending in an area less prone to pooling you should avoid the white when it dries.