Let me clarify a few things. I would also recommend joining my Facebook page, The Reborn Connection, where I have tons of articles, videos and discussions on all this. You can read for hours there and get a good schooling on air dry paints. So this is the basic of air dry paints and reborning.
Always use artist grade paints. Craft grade paints have lots of inert ingredients in them (fillers) to make them cheap and these ingredients can lead to peeling/flaking/fading down the road.
Artist Grade paints contain pigments suspended in an emulsion which contains binders in it to hold it all together as well as bond the paint pigments to the surface on which it was applied.
Air dry paints sold as “Reborn Paints” usually have extra thinning agents and retarders in them to make the paints easier to use. Some of them can be used straight from the bottle or thinned a bit more. Artist Grade paints are usually so rich in pigment strength that they need to be thinned some in order to get the hue and fluidity needed to apply thinly to a vinyl doll.
You can use a little distilled water to thin acrylic paints but it is not recommended to exceed a 30% volume of water to your paint ratio. This is because water will break down the binders in the paints making them less stable and thus less adhesive and more prone to fade. The same holds true of Retarder so it must be kept to a minimum as well. Usually a few drops of that is all that is needed to do its job of slowing down drying time.
When you need your paints thinner then you need to add in a binder to do the rest of your thinning. The most fluid binder would be an air brush Flow Medium such as Golden High Flow Medium or Jo Sonjas Flow Medium. These mediums are like milky water that will thin the paints out very fluid.
Other mediums that can also be used to thin out the paints are Fluid Matte Mediums, Matte Gels and Glazing Liquids. Any one of these or combination of mediums to get the desired effect is fine.
As a side note, do know that Mediums can increase sheen and tack to the surface of the doll. Glazing liquid produces the most sheen followed by Flow Mediums. The Liquitex Ultra Matte Gel is the most matte medium I have found and it is very thick. Next would be Golden Super Matte Medium which is also very matte but not as thick as the Liquitex Ultra Matte Gel. You can use either of these and a little distilled water to thin your paints or you can use either one of them in with the Flow Medium to cut back on some of the sheen and tack of the flow medium. I prefer not to use Flow Medium only to thin with and usually do this.
While the paint layers and mediums are curing the pieces will stick to each other so be sure to have each piece suspended on a peg or something to air dry. Once the pieces are final sealed and varnished this will seal off any tack from the mediums and matte the sheen if you are using a very matte varnish.
YES YOU WILL HAVE ISSUES WITH DUST STICKING TO YOUR PAINTS WHEN YOU USE MEDIUMS SO BE SURE TO KEEP YOUR WORKING AREA CLEAN. The binders in paints and mediums are like glue and do attract dust.
- Cure time: I am C&P this in from the Golden Paints website as it explains it better than I can.
Blockquote The Two Drying Stages of Acrylics
The drying of acrylic paints occurs in two very different stages, hence drying times must be thought of in two different time frames. The first stage, a relatively short period of time, results in the formation of a skin over the surface of the paint. This is the time that it takes for acrylics to “dry to the touch”. At this point, the flow of water towards the surface is no longer sufficient to keep the paint film wet. Very thin films can feel dry within seconds, while thick films may take a full day or more to skin over.
The second stage of drying is the time for the entire thickness of the film to be thoroughly dry. That is, the time required for all of the water and solvent (used as freeze-thaw stabilizer and coalescent) to evaporate and leave the film. This is a most crucial time frame, as the ultimate physical properties, such as adhesion, hardness and clarity, do not fully develop until the film is near complete dryness. For very thin films, this time may be a few days, while films of 1/4 inch thickness or more will take months and even years to be completely dry.
Many artists are not aware of this more lengthy drying time. This is the reason that one may find that a rather thick layer of paint has not adhered to the surface when tested a day or two after application. This same layer of paint will also seem very soft. The skin may have dried sufficiently, but the paint in the center is still wet. Regarding development of clarity in gels and/or mediums, one can allow a painting to clear, store it away and later notice that it has become cloudy. The film may have only been partly cured, and is soft enough to allow moisture from the air to penetrate, turning it slightly milky again. Given enough time for more complete drying, these properties should improve dramatically.
You can continue to paint over layers that are dry to the touch until you are done. It is best to wait 48-72 hours after the last layer before varnishing. Then wait another 48-72 hours before assembly. However, I do not consider the doll’s paint job “stable” for at least 1-2 weeks. If the weather is high in humidity or very cold it can take up to that 2 weeks. Also, if you used a lot of layers of paint such as on an AA baby, and/or retarder in most of your layers that will take about 2 weeks to be fully cured.
I always keep a hair dryer on hand to quick evaporate paint that has retarder in the mix. I use retarder when painting hair and if I apply any caucasian flesh layers to keep them from drying pasty looking. I always hit those applications with the hair dry to dry them to the touch and evaporate the fluids more rapidly. This does influnce overall drying time.
If you have any more questions do go join my group as that is where you will get the most help.