.
Rub-N'-Buf is a paste wax with metallic powder (I assume - it might possibly be coated mica) and pigment. Rub it on, wait for it to dry, buff it. Easy. Smells, acts, and thins like shoe polish. That last statement is the important one. Early experiments show that you cannot put a protective coat of paste wax over Rub-N-Buf without re-dissolving the wax underneath and leaving smears. It being a wax, I haven't even tried getting acrylic gloss lacquer to stick to it.
My earliest experience with this is as you'd expect - get some, goop it on raw plaster, spread it around, and see what happens. What happens is also fairly predictable. You need very little to cover smooth surfaces, and it sticks quite well to dry plaster. Rough surfaces need more, and you need to use a Q-Tip or Kleenex to convince it into crevices, and it can get a bit wasteful. Again, not much of a problem on a one-head sized piece. On the one large piece I did in this, the edges were just too rough and creviced to just keep goobing it in there, so I tried thinning it with isopropyl alcohol. I use the 99% stuff. I don't really know if the 70% stuff will work, but I kind of doubt it. Not much price difference anyway. The second picture is a face (Steve), which has a lot of rough texture on the beard. It's probably not obvious without a comparison piece, but a fair bit of texture is gone from the beard due to glopping on excess wax to fill in the rough spots. Again, this was done manually, rather than sprayed.
.
You can get a pretty good result brushing this on, but on a smooth surface, you'll really see brush marks, because the paint is so thick. You can minimize this by not putting much paint on your brush at a time, and spreading it really thinly. When it starts to get tacky, re-brush it in random directions to cut down on the brush marks even more. Needless to say, this is a bit tedious and time consuming.
The patinas they sell also work well, but best on new paint. The blue patina is much, much more effective than the green, according to my recent experiments. Also, on big areas, it's quite a task to get the entire surface evenly covered with just-damp paint before using the patina.
Well, the reality is that:
NOTE: Health & Safety Copper is bad, bad, bad for you. If you're going to spray patinating solutions, use adequate ventilation, and get a real filter mask. Even with a good mask, I definitely notice some sensitivity, and a bit of coughing. No more spraying indoors for me.
This is the first sprayed patina I did. This is the blonde bronze with blue patina. I adjusted the spray and nozzle height until I had the lowest pressure I could get, and still get an even spray. I wanted a narrow pattern to do the "tears" below the eyes. I'm not actually sure how much of what's on there is actual patina, and how much is just caked-on, dried, copper sulfate. It's a bit hard to gauge how much is enough, as the reaction happens several seconds to minutes after you apply the solution.
The patina went so well, I thought I'd give it a shot with the Modern Options paint. Eureka! The Badger's aperture is comparatively huge, and you can definitely put enough air through it to get a fine mist. This is not to say that the spray quality is anything like as good as the Iwata; it's not. That said, if you're just covering a big area with one color, this beats the heck out of fussing with the fancy brush, or spending a lot on a HVLP sprayer.
Here, pictures of the airbrush setup. The first bit is the regulator downstream of the scuba tank. The yoke and tank are just as with a regular scuba setup. The high pressure gauge is ancient. The proprietor of a dive shop I used to go to sold it to me cheaply. Note that the low pressure regulator has a brass barb, and that is just hose-clamped onto a low pressure hose. This appears to be good enough for the approximately 140 PSI going in to supply it from the tank. On the output side, it's just a short piece of brass tubing. The nut looking thing is the adapter Badger sells. Unfortunately, the adapter is just a chunk of brass, and no seals. The yellow-green glop inside there is some urethane mold-making rubber I had lying around. I put a piece of thick wire through the aperture to keep it open, and poured a smidge of the mixed rubber inside to make a seal. Ugly, but functional.
Next, a shot of the Bager, should you be motivated to get one of the same. I cannot say whether the cans of propellant they sell are worth anything, as I already had the scuba tank setup when I got this. The other two shots are of the nozzles of the two brushes I have. The first one is corrosion on the nozzle from using the patina solution. The second is buildup of Rub-N'-Buf. It wipes off, but if you let it build up too thickly, it will start letting bigger droplets sort of "spit", rather than spraying evenly.
Here's the amazingly low-tech paint filter to keep the paint crusties from clogging the airbrush. Cost about a buck in parts. One piece of 1/2 inch PVC, one slip coupler, and a fragment of brass cloth I had lying around from some other project. Being an inveterate pack rat helps, I guess. Basically, just cut a circle of the mesh a bit bigger than the pipe, cut off a little section of pipe, and hammer the small section home into the coupler with the mesh trapped in the middle. The long section of pipe just slips into the other side. No glue needed. If you're really careful pouring the paint, you can just blow gently into the pipe to force the paint through the crud that collects on the screen. The paint foams more, that way, though.
With this success under my belt, I was emboldened. Plus, the order had several pieces wanting Rub-N'-Buf as the color. Back to the Badger. After a couple of attempts at figuring out the proper thickness, I can recommend the highly scientific mix ratio of one entire tube of Rub-N'-Buf to 2 oz of 99% isopropyl alcohol. Start by dumping the tube into the 2 oz jar. Add a little bit of alcohol, and mix with an acid brush (stiff bristles, disposable) until you've got an even mix. Add a bit more alcohol, and stir again. Now, fill the bottle up with alcohol, and give it a good shaking.
Yes, you get a bit of alcohol fume when applying this. Nothing unreasonable, though. The first few attempts at applying this mix to plaster were highly unsuccessful. Basically, it applied just fine, but when I went to buff it, most of it peeled off of smooth sections. Areas on crinkly texture, like hands was fine, but generally, this was bad. Part of the problem was that I was applying this to dusty pieces that hadn't come out well that I was saving for this sort of experiment. Working with new pieces, though, the problem was only a bit better. The first picture below shows the peeling problem. The second is the result of aggressive buffing. Some of the color transfers from surrounding areas onto the cloth, and then back onto the surface, but not enough to give a fully opaque coat, or to fill the skin texture, so the white still shows through. The final image shows how it stays on crinkly texture without peeling, even after being buffed.
So, something has to give. What follows are pictures of a largeish test piece I did to work out how to spray on the paste wax. I tried a couple of different methods. The first was to just spray on, and try to retouch afterwards. The first picture is of straight spray-on. This is just behind the knee, so the texture is good enough that most of the applied wax sticks anyway. On the left is one coat, and on the right is two coats. After applying with the airbrush, the surface was rebrushed with a very soft bristle brush and more alcohol. Drippy, and messy. Works fairly well, though.
The next effort is similar. One coat on the left, and two on the right. Rather than using soaking with alcohol to bond the wax to the substrate, this one is with a torch. If you keep the torch moving fairly quickly, the wax doesn't seem to suffer, though I got some fairly distressing cracking/pinging noises from the plaster itself. This particular piece is FGR-95 and fiberglass. I'm not too sure how TufStone would hold up to this, but I was fairly confident that the FGR would do OK - this is how I cut down on glass fibers sticking out of mother molds - but I do that torch work while the plaster is still wet, and the driven off water takes most of the heat, and limits the maximum temperature. This method of adhering the wax seems to work fairly well, but would need a lot of practice to get good. Also, the torch probably is doing damage to the piece that's not immediately obvious - Plaster calcines (drives off the water of crystallization) above 125 degrees Fahrenheit. This makes it more crumbly, theoretically, but when buffing out, I didn't notice any difference.
Next try was to put down some acrylic base as a primer. I used "Art Base 'A'" from Douglas & Sturgess. This looks like a pretty vanilla acrylic carrier. Cheap, cheap cheap. They also carry an "Art Base 'B'", which smells like, acts like, and probably is, polyvinyl acrylate (white glue). Useful, but not as a paint base for me - waay to thick. See the finish page for a use with tissue paper, though. The first picture is of Rub-N-Buf over straight acrylic. It's pretty textured. It seems that the thick acrylic doesn't quite flatten out when the droplets hit and dry. A bit hard to see, but look at the outer edge of the foot at the left side of the picture.
Mixing the acrylic with about half water makes it go on much more smoothly. A couple of drops of color make it easy to see where you've covered. The water has an additional benefit. If you overdo it, you can mop up the excess with a paper towel without having the edges of any drips having dried out and leaving ridges.
Applying two coats or so over this primer gives a nice finish that doesn't buff back off, even on relatively smooth texture as on this shin.
Lastly, here are the green and blue patinas over the blond bronze base. The "green" isn't terribly green, though - more blue. These were sprayed on to the paint just after it had lost its gloss from being wet. Most of the patina is actually captured under the acrylic's surface. On the blue, though, there's just so much crud that you can smear it around with your fingers, though it takes a bit of work. The final picture is of Rub-N'-Buf's Antique Gold over the acrylic primer.
