(adsbygoogle = window.adsbygoogle || []).push({}); [Feb 2016 Update: If you want to add an integral sink to your countertop, make sure to also check out the tutorial on how to make a concrete counter or vanity with integral sink. Here’s the one I made…] (adsbygoogle = window.adsbygoogle || []).push({}); Now back to our regularly scheduled program… In the last post, Part 1 – Intro & Templating, we worked on creating the template for building the form that will give your countertop it’s shape. Now, we will actually be building the form. (adsbygoogle = window.adsbygoogle || []).push({}); The form is built from melamine board. Melamine is basically particle board covered with a white melamine sheath. You’ll often see it used for shelving. It comes in various sizes and can be purchased at most home improvement stores. We used two large 48″ x 96″ (3/4″ thick) melamine boards to configure our form, but of course, adjust for the size you are building. Use clamps to secure your template to your board. To make this as easy as possible, align the back edge of your countertop template to the straight edge of the board. You can see how we did that on the left side of the image above. Use a pencil to trace along the inside and outside of your template. Tracing along all the interior edges will simply help you stay oriented on the board once the template is removed. If you’ll be using decorative edges on the front and sides of your countertop, add that additional width to the edges where the decorative edges will be placed, i.e, if your edge mold is 1″ thick, add one inch to the sides that will accommodate the molds. Next, X-out all the open spaces on the board. This is simply another tip for staying oriented. It will tell us that the X-out surface will face down when pouring the concrete. Why? Because when we pour the concrete, the surface we pour it on will end up being the top surface of the countertop. Therefore, you’ll be pouring a mirror image of the template, so we turn over the board. Use a skil saw (or other electric saw) to cut the outside edges of your marked form. Be as accurate as possible (obviously). Place your template over the cut out form to double check for accuracy. In the photo below, on the left side, you can see how we left extra space for our edge molds. On the far end of the image above, we wanted a rounded side to create a space for bar seating on that end of the countertop. So we used a bent piece of plywood strip to outline a gentle radius on that end of the countertop and then cut. As mentioned earlier, we built this countertop in two pieces. So, next, we will create the joint where the two pieces will connect. In the image above, we used two melamine boards to create this form. You can see in the middle of the photo where one board over laps the other. If you are using two boards to create your form, then with your boards overlapping, use your template to make sure everything is aligned to the template and then reclamp the two boards together. Your joint doesn’t need to be straight. We decided our joint would mimic a marble vein, and drew it on with pencil. Notice that the joint overlaps the doubled boards. We will be using the bottom board as the second part of our countertop form. Use a jigsaw to cut through the doubled boards. When you remove the cut piece in the image above, the two parts of the countertop should fit together perfectly. Notice no writing on the melanine? That’s because we also flipped the board. Remember, we’re pouring the concrete on a mirror image of the countertop. So the writing is now on the side facing down. Now, it’s time to create the form edges. First, we’ll create the mold edge for the joint (you know, that crooked part that we cut to mimic a marble vein). If your joint is going to have a straight edge, you can skip this step and simply use the 2 ¾” melamine strips that we’ll discuss below. But if you are making a crooked joint then read on.. Use roofing paper to form the crooked joint edge. Why roofing paper? Simply because it’s a heavy material that can be easily formed and hold it’s shape. Cut a strip of the roofing paper 2 ¾” wide. Crinkle up the roofing paper to give it a more natural stone-like finish (since we’re mimicking a marble finish). Slide your crinkled roofing paper into your vein joint and press the two sides of the countertop form together to hold it in place. Ta-da. Now, we’re ready to install the external edges. CONTINUE READING… For the external edges cut 2 ¾” strips of melamine. Since the melamine is ¾” thick, this will give us a 2″ thick countertop. Use a finish nailer to attach the 2 ¾” melamine sides. And here’s a tip: you don’t need a million nails. You do want to be able to take the form apart later on, so one nail ever 12″ or so will do. If your countertop has a curved edge, use a 2 ¾” wide strip of the ¼” plywood you used to create your template for that edge. Here’s what your form will look like at this point… Don’t worry about those open interior corners. We’re going to fix that in a minute when we add our decorative edge molds. There are many different decorative edges you can purchase. We chose a decorative rope edge made of a polyurethane rubber. You can check out different mold edge options here. Use a brad nailer with 1″ brad nails to attach your edge mold. You want to shoot your brads in through the thickest sections of the mold. The brads will sink slightly into the rubber so you will not see the brad heads shaped in the finished concrete product. Some decorative edges do have an obvious top and bottom. Ours didn’t. But if you use an edge with a top and bottom, make sure that the top is installed downward since at this point everything is upside down and we’re working with a mirrored image. This is what the attached edge mold looks like… See how we now have those opened internal edges covered. For fun, we decided to add a broken flagstone edge mold on one corner… Notice the little cut blocks behind the mold? Those are nailed in and will give that edge some curves. You can also see that that side is our radius edge where we used the ¼” plywood instead of the melamine board to enclose the side. Seal all joints by running a bead of 100% silicone black caulk over the joints, including the roofing papered joint. Then smooth the caulk with the side of your finger. It’s recommended to use black because it’s a lot easier of see on the white surface. Be sure not to leave any smeared caulk on the melamine. Any impressions, no matter how slight will show on the finished product. If you do get caulk smears, clean them up with a cotton cloth. Now, let’s work on creating the hole or “block-out” for the sink. The block-out is cut from a 2″ polystyrene panel. These panels are generally used for insulation and can be found at most home improvement stores. In the above image, we’ve already cut the sink block-out. New sinks usually come with a cut-out template. If you have a template, trace the template onto to the polystyrene and cut it out. We used a band saw to cut the polystyrene, but a jigsaw will work great too. If you don’t have a template, turn the sink you will be using over and sit it upside down on the polystyrene so that the drain opening is facing up. Then stick your hand through the drain opening and trace along the inside edges of the sink. Cut out your traced form. Use a sanding block to smooth out the edges. Wrapped your smoothed edges with 2″ PVC tape. Ben recommends the Orbit brand tape. It’ll give you a super smooth finish to the inside edge of your sink. This is the part where we take a short intermission so Lily can go potty… Yes, I brought my furry little monster to class. There’s a long explanation that you can read about here. Needless to say, my attempts to be inconspicuous with the pooch lasted about five minutes. So not only was I the only female in class, but I was the girly girl with the pocket pooch, and not ashamed of it damn it. :-) Now back to our regularly scheduled program… Next, remember your template? Lay it over the prepared form. To support the template on the form, cut out a few blocks of scrap polystyrene and place it under the template. On the right side of the image above you can see what I mean by using scrap polystyrene to support the template. Once you have your template all centered, find the spot where you marked the sink center. Use your center mark to center the sink block and attach the sink block to the melamine with a couple of 2½” screws, making sure to leave room on the back of the sink block for a faucet hole. Caulk the sink block-out. Center your faucet hole plug and screw it into the melanine with a 2½” screw. The faucet plug doesn’t need to be caulked because it will be covered by the faucet after everything is installed. The final step in preparing your mold is to cut and place a small block of melamine over any outside corner edge molds (see arrow below) and use your brad nailer to nail them down. You’ll notice when bending the edge molds on the outside corners, they will tend to wrinkle slightly on top. These blocks will help keep the integrity of the mold shape on those corners. As you can see in the above image, those blocks are not necessary on inside corners which do not wrinkle. And there you have it. Your mold is complete. Now, check out Part 3 of the series: Mixing and Pouring Your Concrete. And don’t forget to sign up for email alerts so you never miss a fun DIY… [Special thanks to Countertop Solutions for inviting me to sit in on their class so I could bring you this fun tutorial!] This post linked to some of these totally fabulous blogs and Remodelaholic. TweetPin It