I’ve always had a thing for brick walls. They have so much texture, depth, personality. Brick makes everything better.
So when I thought of making a dollhouse for my daughter, my mind immediately said “brick”! I’ve watched a lot of tutorials on how to make scale bricks, from making forms out of foam core to cutting a slab of clay in the right sized rectangles. You can also laser-cut your brick pattern into MDF and just paint the bricks and grout lines. I even saw a few people recommend painting foam bricks or gluing brick-sized cutouts from egg cartons to your wall.
But I’m a sucker for authenticity, and so decided to go perhaps a little too far in the direction of laboriously handmade.
I dusted off my barely-there CAD designing skills I picked up last year to start things off. I fiddled with the 3D modeling to make an inverse of the brick mold. And since I’m fortunate enough to have a husband who likes to 3D print things, he fired up our MakerBot and printed up a lovely hard plastic form for me to work with.
Looking to print the brick mold yourself? Download the CAD file (STL format)
I chose a paint on rubber (Mold Builder by Castin Craft) to make the mold with, which indicated carefully painting 11 coats of rubber onto what you want to make a mold of. The only problem was that each coat needed at least 6 hours to dry, and preferably 12. So if you add to that the fact that I just did a coat whenever I had time, it took me
several weeks a month to get the mold finished. Despite the long time lapse, the rubber captured detail better than expected and it’s lasted well through regular use.
As I was making the mold I did some research into what types of material to use to make the bricks. I ended up deciding on plaster of Paris as it sets quickly (under an hour), is easy to clean up, and pretty cheap. I also have fond memories of making Richard Scarry molds with it as a child. My backup option was to be cement since Plaster of Paris isn’t waterproof (it might melt in the rain), but in this case, it wasn’t a big concern.
One of the things you have to be careful of when doing any sort of casting is the dreaded air bubble. If you don’t get those suckers out before your medium sets you have holes in your beautiful cast. I ended up going with the tried-and-true (as well as free) method of just tapping the mold until air bubbles stopped coming to the surface. But if you’re going to be making a lot of bricks you might consider a cheap vacuum degassing rig – basically a shatterproof vacuum jar and a vacuum pump to force the air bubbles to rise to the surface.
I ended up spending a lovely evening playing around with iMovie to share my method for brick making. Wanna see?
My Brick Recipe
2019 update: I realized that I never posted the recipe for bricks! You’ll need:
- 1/4 cup water
- 1/4 tsp cement color
- 3/4 cup plaster of Paris
Mix the water and coloring together in a disposable cup. Add the Plaster of Paris and mix well. Spray the inside of your mold lightly with Windex to reduce surface tension and prevent air bubbles. Pour the Plaster of Paris mix into the mold. Let sit for 45 minutes to 1 hour, then remove from the mold.
Bricks can be sanded or weathered if needed – since the coloring is part of the brick (not painted on top) it’ll look authentic!
Materials & Costs
If you want to tackle a project like this, you’ll need a few materials. I bought my first box of plaster of Paris at Michael’s but heard a rumor that you can find it in the paint section at hardware stores. Turns out it was half the price!
I also used popsicle sticks and plastic cups so I could dispose of them. It ends up being more garbage in the landfill than I’d like, but I heard that plaster of Paris will clog up your drains if you rinse the extras down the sink. Yikes.
- Castin’ Craft Mold Builder – $17.99 (Michael’s)
- Dap Plaster of Paris – $5.99 for 4 lbs (Lowe’s)
- Quickrete Liquid Cement Color – $14.99 (Lowe’s)
- Plastic cups for mixing – $1 (dollar store)
- Popsicle sticks for stirring – $1 (dollar store)
The materials above let me make around 325 bricks before I had to stop in at the store for more plaster of Paris. The cement coloring was only about 1/4 used, so I’m guessing it would be good for around 1300 bricks.
If you’re looking to make your own scale bricks, I found the chart on Wikipedia very helpful. For the 1:6 scale bricks I made here, I just divided all the dimensions by 6:
|Australia||9 × 4⅓ × 3 in||230 × 110 × 76 mm|
|Canada||7⅝ × 3⅝ × 2¼ in||194 × 92 × 57 mm|
|Denmark||9 × 4¼ × 2¼ in||228 × 108 × 54 mm|
|Germany||9 × 4¼ × 2¾ in||240 × 115 × 71 mm|
|India||9 × 4¼ × 2¾ in||228 × 107 × 69 mm|
|Romania||9 × 4¼ × 2½ in||240 × 115 × 63 mm|
|Russia||10 × 4¾ × 2½ in||250 × 120 × 65 mm|
|South Africa||8¾ × 4 × 3 in||222 × 106 × 73 mm|
|Sweden||10 × 4¾ × 2½ in||250 × 120 × 62 mm|
|United Kingdom||8½ × 4 × 2½ in||215 × 102.5 × 65 mm|
|United States||7⅝ × 3⅝ × 2¼ in||194 × 92 × 57 mm|
I’ve switched to making my molds using pourable silicone: Mold Star 20T from Smooth-On. It’s more durable, looks nicer, and is faster to make molds with. Just spray your 3D-printed form with Universal Mold Release, mix your two parts of silicone, pour, and wait an hour. Et voila, a beautiful new brick mold.
Just comment below and I’ll get back to you. Happy brick making!