Please read through all of the instructions in order. Some of the tips in the first sections are not repeated in the latter ones, so reading through all of the instructions will help you pick up all of the tips. The demonstration videos for each segment will help you see exactly how the paint is applied to the model.
The Antiquing Method
Coloring and Sealing Pieces
The antiquing method shown here is used on the Egyptian Tower mold. This method works great for blocks with the sand blasted texture but does not work well with other textures such as the chipped stone.
Before you can apply stain, the pieces must be colored and sealed, or the stain will soak into the blocks, turning them a dark brown. It's best if the blocks are a light tan color.
You can make the blocks a light tan color by either:
1. Painting them tan using acrylic craft paint.
2. Using tan colored plaster and sealing it with varnish.
Painting Pieces a Tan Color.
This is the easiest method for students doing a school pyramid project.
Since plaster of Paris is the easiest casting material to get, most students will have white building blocks. Painting the plaster is the easiest way to color and seal it before staining.
You'll paint the blocks using acrylic craft paint. This is the kind that cleans up with water. An 8 ounce bottle will be more than enough to paint the whole pyramid and will cost you about $4.00.
Use a light tan color of paint!
For these photos I used yellow paint, and you'll see that the finished pyramid ends up being too orange.
Use a wide brush to paint the pieces. Do not miss any spots!
At this point I'm wondering "maybe I should have used light tan paint instead".
How to apply shoe polish is shown below. Be sure the paint is completely dry before putting the shoe polish on.
Well, the pyramid is fairly orange, but it still doesn't look too bad. You would get better results than mine if you used a light tan color of paint instead.
Applying a clear Protective Coating.
Since this method lets the original color of the blocks show through, you must use a colored plaster for the blocks! I'm using a tan colored dental plaster for these examples.
You can color white plaster using cement colorant which is used to color concrete (used on sidewalks), or you can buy colored plaster as shown on the Dental Plaster page.
The way this painting method works is that you completely seal the model with a clear coat, then apply a stain to it. The clear coat keeps the stain from soaking in.
I'm using a water-based sealant. It's like varnish, but they have to name it differently. A water-based sealant works better because it's easier to clean up and is more resistant to oil-based stains.
What I'm using is called "Polycrylic protective finish" from Minwax. Be sure to get a satin for flat finish, because the glossy kind will make the model look odd.
Be sure to cover your work surface with a trash bag to keep varnish off of it.
I suggest using a plastic glove on your left hand while painting. This will keep varnish from getting all over your hand.
You can find these in the women's hair color section, but be sure to get the larger sizes. My wife's gloves were cutting off the circulation pretty good.
Start by slopping the varnish on and letting it run into all the cracks. You'll know when you've painted an area because it will turn darker when the varnish soaks in.
It's extremely important that you do not miss any spots! If you miss a spot, then the stain will soak down into that area and you'll have a really dark spot on your wall.
When you're finished painting, wipe up the excess drips of varnish off the piece before you set it aside. Let it dry completely.
Using Brown Shoe Polish.
To stain the model, I'm going to use "Kiwi" brand liquid brown shoe polish used for leather.
The easiest way to get the polish out is to put the edge of a screwdriver under the red band and twist. The top should pop right off. Then pour what you need into a small cup. It will be easier to use a paintbrush this way.
This shoe polish cleans up with water (before it dries).
Be sure to put a plastic glove on to keep from staining your hand. Paint a liberal amount of shoe polish onto the piece. Be sure the shoe polish gets down into all the cracks when painting it.
Since the piece has been sealed, the shoe polish will not soak into the wall and will stay liquid for a long time (maybe 5 minutes). This will give you time to wipe off and add more stain before it dries.
The shoe polish has a slight odor to it, so work in a well ventilated area.
Using a paper towel or cloth, wipe off the shoe polish. Be sure to wipe up any drips that may have happened around the sides of the piece. If drips are left for a long time, they will put a dark stain where you don't want it. For small areas you can use a cotton swab.
Shoe polish works better than an ink wash because it's thicker. If you tried this with an ink wash, the paper towel would soak up the wash out of the cracks, and the effect would not be as noticeable.
Also, shoe polish dries slowly so you have time to wipe off and add more stain without it drying on you. Do not use latex paint as a stain. It dries much too quickly.
Here is a close-up of how the finished wall section will look. The shoe polish has a bit of a reddish cast, but I thought it came out very nice. You could dry-brush highlights onto it, but since this was supposed to be a quick and easy way to paint, that kind of defeats the purpose.
These walls had a slight sheen to them, but not all that noticeable. You can always spray a dull protective coat over it to kill the sheen.
Using Gel Stain.
For this second example, I'm going to use oil based gel stain. Gel stain is a little harder to find, so look for a large hardware or paint store that sells wood stain.
If you're going to use gel stain, be sure to use a water based varnish to seal the piece with. If you use an oil based varnish, the solvent in the gel stain will soften the varnish and the piece will come out much darker.
Gel stain has a few advantages over shoe polish:
It has a wider variety of colors to choose from.
It has less of a smell than shoe polish.
It's thicker than shoe polish, so you have more control when you apply it.
It also has a few disadvantages:
It's more expensive (about $4-$5 per can).
You have to clean up with paint thinner (mineral spirits).
The color of gel stain I'm using is colonial oak. It's a bit darker and browner than the shoe polish (not as red).
Gel stain is applied the exact same way as shoe polish (above). Paint on a thick layer and jam the brush down into the cracks. Gel stain is slightly thicker than shoe polish, so you'll have to jam the brush in a little more.
Wipe off the gel stain with a paper towel. Because it's thicker, you'll have a harder time removing it from deep recessed areas such as the decorative trim. For small areas you can use a cotton swab.
You'll have to wad up a paper towel and jam it into these areas to remove the stain. The stain dries slowly so you can go back and wipe off the excess several minutes after you apply it.
Overall, I like the look of the gel stain more than the shoe polish, however my wife prefers the shoe polish.
I like the thickness better, because you have more control over light and dark areas depending on how much you wipe off or leave.
Gel stain also dries flatter, so there's no need for a spray of dull coat over the finished model.
Do not use latex paint as a stain. It dries much too quickly for it to work.
In conclusion, I think this method will open up a few possibilities for painting. I haven't had time to experiment with it yet, but here are a few other things I've thought about:
Use light gray plaster and black shoe polish on gray color schemes.
Using white or yellow plaster and see how that affects the stain color.
Dry-brush a white or light cream color paint over the top.
Using cement colorant in varying degrees to color the plaster. You should see the variation of color in the blocks through the shoe polish.