Introduction: Street-Art Inspired Concrete Wall Art W/ Hidden LED Backlighting
I collaborated with my friend Ariel (Instructable name: relg) to make this Concrete Agamograph with a walnut backboard and LED backlighting. We made triangular pieces from Quikrete Q-Max concrete mix in a melamine form, and used Fuse-it adhesive to attach them to a walnut plywood backboard. Behind the walnut board we attached an inset rectangular plywood frame with a french cleat for hanging the piece. We also added an LED strip around the inset frame to provide backlighting.
Step 1: Material List
1. 1 bag Quikrete Q-Max Pro Concrete
2. 2'x4' Walnut plywood (from home depot online)
3. scrap plywood
4. RGB+W LED strip (kit with controller and power supply: http://amzn.to/2wwcVOi
5. spray paint (colors of your choice)
6. paste finishing wax
7. 100% silicon caulk (black): http://amzn.to/2xFV3G0
8. ball fondant tool: http://amzn.to/2foY9mK
9. walnut edgebanding: http://amzn.to/2whFrbm
11. polycrylic (for finishing walnut)
12. whatever screws are needed to attach to your wall
1. Circular Saw or Table Saw (or both)
3. Conrete Mixer (or mixer drill attachment for corded drill)
4. Miter Saw (optional, but makes life easier)
Step 2: Build the Form for the Concrete
To build the form, we first a bunch of long right triangular pieces on the table saw. To get them identically sized, set your blade at 45 degrees, make a cut long ways at the edge of your melamine sheet. Now adjust your table saw to the width equal to one side of one triangle you'll paint on. Flip your sheet over so the outer protruding edge of the 45 degree side is on top and abuts your table saw fence, and run it through the table saw to cut your first triangle out. You can then just flip your sheet, cut flip, again, cut, and so on to cut long triangular strips. Then take your triangular strips to the mitre saw and cut them to the height of the agamograph. This process for cutting triangular pieces is shown in the video here.
Now set out the triangles on a backer piece (we just used cheap 1/4" MDF), and put two triangles together to make each triangle in the corrugated base of the form. Once these are laid out, measure the heigh of each triangle.
Then cut strips of melamine using your table saw to the same height as the triangles. (This means that each concrete triangle can be treated as a separate piece.)
Before assembling the form, apply paste wax to the triangular pieces and inside edges of the sides.
Then place the sides of your melamine form around the corrugated base you just made, and attach the sides to the base using a hot glue gun. Then use 100% silicone caulk and a fondant ball tool to caulk all your edges (check out my past instructables on concrete for details of this process). After you peel away excess caulk, its time for concrete.
Step 3: Pour the Concrete
We just used Quikrete Q-Max mix out of a bag. It is higher strength than any other bag mix you can buy at a big box store, which is important for the triangles, since they are fairly thin (ours were about 1.5" tall at the peak). Just follow the directions on the bag to mix it, and place it by hand into the form. You can see this process here.
Step 4: Demold the Concrete Triangles
After letting the concrete cure for at least 48 hours, it is time to demold. Flip the form upside down and remove the bottom. Then pull off the sides (using a rubber mallet helps), and carefully remove the triangle parts of the form. If you have trouble removing any part of the form, check and make sure there isn't some silicon that is holding it together -- if there is, just peel the silicon off first, then try again and it will likely come right off. Now set your triangles out on a table and admire the 3D canvas you just created.
Step 5: Paint Each Side of the Agamograph Separately
How you paint is really up to you. We used spray paint and let it drip, flipping it over between sides, so the drips met in the middle.
In order to paint one side at a time, take the triangles from your concrete form and use double sided tap to attach them to your triangular concrete pieces, each concrete piece and the attached form piece make a square. Two sides of the concrete triangle will be exposed. Now put painters tape on one side of the triangle, and line up the squares so the side without tape is exposed and the taped side is hidden. Then use gorilla tape to hold the squares together to make a continuous surface to paint on. After you paint and let it dry, untape the pieces, then repeat the above process to paint the other side. This process is shown in the video here: https://youtu.be/35-n2bLOHHs?t=361
Step 6: Cut the French Cleat Frame and Attach to Backboard
I forgot to snap photos of this step, but you can see it well at this point in the video. We used a 2'x4' sheet of 1/2" walnut plywood from Home Depot (shipping on this size sheet is very reasonable, so it is easy for city dwellers to acquire). We cut it down to 40"x20", and then applied walnut edge banding to the sides.
Then we cut a frame of 4 pieces from scrap plywood. To cut the top piece, I first cut a piece of twice the width I needed to the length we needed. Then I cut this top piece in half with the table saw at 45 degrees, to create two sides for a french cleat. (Google "french cleat" if you aren't familiar with this, or watch the video for more details). We then attached the four sides of the plywood frame to the back of the walnut plywood sheet with screws, making sure to countersink screw holes so that the plywood could sit flush against the wall when hung.
Step 7: Attach the Concrete Triangles to the Backboard
This was straightforward. We used a product called Fuze-it by Liquid Nails to attach the triangles, and it was awesome. I will definitely be using it again! Amazing the hold it has.... You apply it with a caulk gun like other adhesives, but this stuff just works.
Before you use the Fuze-it (or other strong adhesive), lay everything out and make sure you've got the pieces where you want and lined up in the middle and level with sides of the walnut plywood. Then start at one side, pick a up triangle, apply adhesive, press it down to adhere it, and move down the line until all the triangles are done. Then wait overnight for the adhesive to cure.
Step 8: Attach LEDs to Rear Frame
This process is shown here in the video. Basically, you just use the adhesive backing of the LED strips to stuck them to the outer part of the plywood frame, behind the walnut plywood backboard. This way, you don't see the LEDs, but they provide a nice backlight glow.
We used this RGB+W LED strip: http://amzn.to/2wvTJAg I really like them because they have separate warm white LEDs, along with standard RGB LEDs. Normal RGB LEDs don't have a very nice white (very blueish) IMO, but the colors are fun. This gives you the best of both worlds since you can turn on the warm white LEDs only, or turn those off and turn on the RGB LEDs to your color of choice (or rotate colors).
Step 9: Hang It on the Wall
We just used a standard french cleat system (which was integrated in the LED backlight frame), to hang it. Basically you attach the plywood strip with the 45 degree edge on top, and angling up and out from the wall, and make sure it is perfectly level. So long as you attached the mating piece (in our case, the top of the LED frame) level, it will be perfectly level when you hang it on the wall. There are lots of instructables and videos out there showing french cleat systems, so I won't go into a lot of detail, but you can see how we did it here.
We also used this cable management system to tidy up and disguise the wires from the LEDs: http://amzn.to/2x3XykK
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