FREQUENTLY ASKED QUESTIONS
Have questions? Get answers! Check out the Q&A below for the solutions you need. Need more help? Contact Us for additional questions beyond those listed here. We look forward to hearing from you!
Safety
Unfortunately, no. ShapeCrete has the same thermal characteristics as concrete and it would certainly crack. It could be used for the outer shell to shape a nice dome, but it would have to be separated from the high heat with fire-brick and an insulating layer of air. We suggest finding detailed information for building the pizza oven with other high temperature-, fire-safe material and using ShapeCrete only as a decorative outer layer.
Yes, ShapeCrete will perform underwater. However, for best results we highly recommend applying a non-toxic epoxy liner like Pond Armor, which will also be best for our bird and fish friends if you plan to make a birdbath or pond!
ShapeCrete is not fireproof and it will crack and decay overtime if placed too close to an intense heat source. The hibachi grill shown as a project in the project guides is separated from the coals with a wire screen and 2" of lava rock and air can vent from both ends. When we measured the heat on the sides closest to the coals in the wire, temperatures were in the 250 F degree range.
When we use concrete for our firepits, we have the fire itself in a metal wok surrounded by 10" of lava rock and plenty of air circulating through the lava rock. We recommend a fire-brick liner with some physical space between the fire-brick and the ShapeCrete surface. It is a legitimate worry to have too much heat directly in contact with ShapeCrete or any concrete-based product for that matter.
It does depend a lot on the design, and if you have a large buffer of lava rock for example, it might be fine, but we can't recommend using it to make a wood burning fire pit. It will work in more decorative applications with an alcohol or gas flame. These burners usually have a metal surround that will absorb and dissipate most of that heat.
You might consider looking into a making a concrete mix with 'refractory cement' for best results with a fire pit. Or design around an existing metal fire ring, with a buffer zone of volcanic rock, and then the ShapeCrete surround. You'll have better luck with long term durability that way.
ShapeCrete is a portland cement-based product prone to creating dust, so you should take the same precautions you would when working with a concrete mix or gypsum plaster. Always wear a dust mask, gloves, and eye protection when mixing.
Safety First: Wear gloves, safety glasses and protective clothing at all times when working with ShapeCrete. Wear a dust mask when measuring and mixing dry ShapeCrete. Click here for safety data information.
When using ShapeCrete, children under 12 should be supervised by an adult. Store material properly and keep out of the reach of children and animals.
Unsealed ShapeCrete should NOT come in contact with food. Many foods can contain acids or enzymes that will eat away at the surface. Over time, the piece will stain and become unsanitary. Additionally, if the piece has been colored, the pigments themselves could be toxic. For these reasons we don't recommend eating directly off a piece of ShapeCrete.
Sealing with an FDA approved food-safe sealer makes ShapeCrete suitable for making countertops and tabletops and helps protect the surface from exposure to food. In other words, food sitting on the surface is not going to be harmful if sealed. However, eating out of a vessel of concrete or ShapeCrete is not safe because of the various acids in the food in constant contact will eventually eat away at the surface and bacteria will lodge in the pores. Seal it with food safe non-toxic two part epoxy coating and it would be food safe for countertop and tabletop use only. We recommend applying this food-safe sealer: Max CLR - Epoxy Resin Food Safe.
Coloring/Painting/Staining
Dry pigment is mixed in with the ShapeCrete powder and then blended thoroughly. Break up any small clumps of pigment until the mix is a uniform color. Then add the dry mix to the water. Watch the video for more details.
If you use too much pigment, it will weaken the finished piece. In general, for every 1 lb. of ShapeCrete mix, you should only add 1 ounce of pigment. Use a kitchen scale to help determine the exact amount of pigment you need. Or just experiment!
Watch the Video to see how to add powdered pigment to the mix.
Follow the paint manufacturer’s recommendation for sealing to make the color last.
ShapeCrete is a grey portland cement based product and is medium grey in color. It can be pigmented, stained or painted just about any color.
Any paint suitable for concrete will work with ShapeCrete.
Wait 4-5 days before Painting or Staining. Paints or stains can be sprayed or applied by brush.
Paints such as acrylics will work on a slightly textured surface of ShapeCrete. Using the manufacturer’s recommended primer will produce a more durable paint job.
Staining with dyes will yield a very natural look as the stain is absorbed into the ShapeCrete surface. If the surface is hyper-smooth, stains will mottle and be “organic” looking.
There are a lot of different types of concrete pigment that will work to color ShapeCrete. We recommend powdered pigment additives, such as Sakrete Cement Color which are for sale in the same aisle as ShapeCrete.
Release Agents
Casting ShapeCrete into various forms requires different ways of releasing from the molds. Shiny plastic molds, for example, releases without any release agent. With other molds or objects made of wood that you might be trying to cast directly against, it’s important to try different types of form releases.
Different types of forms require different release agents. Raw wood can be sealed with oil, lacquer, or petroleum jelly. Plastic forms can be sprayed lightly with Pam, WD-40, or any vegetable oil / gear oil in an aerosol form. Rubber molds can be sprayed with a silicone and oil based release agent like PolEase 2300.
In general, if your form isn't going to absorb water, you won't need a release agent. Any form that absorbs water needs to be sealed before casting. If moisture is sucked out of the piece while curing, it will leave a chalky, dull finish.
Using too much form release can also stain the surface or create small air bubbles in the surface. Watch the Video to see how to use form release in a plastic mold.
Motor oil or other heavy agents may stain or discolor.
Sanding
Sanding ShapeCrete after it has cured is possible, but because it cures to a stone-like hardness, it's tedious unless you have the right tools. Diamond polishing pads make the job practical.
It's easiest to tool and smooth ShapeCrete during the casting process. After the piece has cured, it becomes extremely hard and sanding can be tedious. For most projects, sanding is limited to cleaning up the edges of a piece and knocking down small imperfections.
After curing for a full 24 hours, you can do a test with a diamond pad. After 48 hours, it will be hard enough to polish and sand.
The fibers in ShapeCrete increase its tensile strength and minimize cracking. You won't normally see the fibers in the finished piece, but if you do, they can be burned off with a lighter or a butane torch.
Diamond Hand Sanding Pads are the best way to sand and polish small areas. Wet “sanding” with a Variable Speed Concrete Polisher and Diamond Pads are best for moderate to large areas.
Carborundum sandpaper is less expensive and can be used from 50-grit to 400-grit, but it will take a long time. Diamond pads from 100 - 600 grit are recommended for more professional results. Diamond Hand Polishing Pads are relatively cheap and can be used on a variety of materials, like ceramics, stone, concrete, and glass.
We don't typically like to use the term "perfectly smooth" as that is determined only in the eye of the user, but, yes, it will take on the smoothness of the glass, metal or acrylic surface and reflect the finish in the ShapeCrete surface. Basically, The shinier the surface, the "shinier" or smoother ShapeCrete will be.
Sealing
While you don’t have to seal your project, sealers reduce the natural porosity of concrete and this will help create a resistance against staining. It's recommended for projects that you want to minimize natural wear and patina. Ultimately, use a sealer—or don’t use a sealer—depending on what type of concrete surface finish you desire.
It’s best to wait 4-5 days before painting or sealing, so that all moisture has left the piece.
Any penetrating concrete sealer, either solvent or water-based will work fine.
For tabletops and countertops, use a food-safe sealer like CHENG Countertop Sealer.
Only a food-safe complete epoxy coating is recommended for objects that will contact food. Containers made from ShapeCrete should NOT be directly used for food. For instance, a ShapeCrete dog-bowl should have a glass, metal, or food-safe plastic liner to actually contact the food.
Tabletops and Countertops that may come in contact with food should be sealed with a food-safe Sealer like CHENG Countertop Sealer. Different foods and condiments will stain and etch the surface of the piece, but keeping a good coat of sealer on it will help minimize the damage and keep the piece looking nice over time.
Repairs
ShapeCrete can be repaired with 2-Part Epoxy or Construction Grade Adhesive. Craft glues or Spray Adhesives aren't going to create a very strong bond.
If the mix has not started curing (within the first hour of mixing with water), ShapeCrete can be re-tooled to smooth out cracks or fissures and you can add more ShapeCrete to your project for building up thickness.
After the piece has cured for 4-5 days it can be fixed with a strong epoxy or construction adhesive.
Cleaning Up
Bonus Projects: Always have a few small projects ready to go so you don't waste any mix. Small molds made for chocolate and soap work great for this!
Throwing it Away: If you do need to throw away excess mix, slurry water, washout or waste material, DO NOT POUR IT DOWN THE SINK OR DRAIN! After you've added water, this activates the cement and it will harden with time. Putting it down any drain will cause problems. The best way to get rid of extra mix is to allow the sun to evaporate the water and then put the remaining solids in a plastic bag and dispose of it in the trash.
Protect the Surface: Making things with ShapeCrete is something you can do on the kitchen table. However, you should lay a big piece of plastic or a tarp across the surface to protect the tabletop. When you're finished making, you can take the plastic outside, clean it off and reuse it, or you can just ball it up and throw it away.
Wear Gloves: It's important to wear gloves when mixing and working with the material. If you're going to reuse your gloves, make sure NOT to wash them in the sink. Active cement should never go down the drain. Wash your hands off outside with a garden hose, or clean them with paper towels and throw the towels away.
Minimize Dust: When mixing, be careful not to make a lot of dust. Always wear a dust mask when mixing. Gently add the mix to the mixing bucket so it doesn't make a big dust cloud.
Clean Up: Clean up is a lot easier to when the mix is still wet. You will be chipping ShapeCrete off of your tools if you don't take care to clean them as soon as you've wrapped up your project.
Storage
Reseal the lid and store the mix indoors, in a dry place. If the mix is stored outdoors, it may absorb moisture, which will cause the cement to harden and ruin the mix. If you don't plan to use the mix in the next few months, tape around the lid to help make sure it has a water-tight seal.
Unused mix in an air tight container will have a shelf life of 6 months to 1 year in the right conditions.
KEEP OUT OF THE REACH OF CHILDREN AND ANIMALS.
Other Common Questions
Try using an acrylic bonderizer (Acryl 60 is an example of one brand)for concrete as an adhesive. Paint it on, then trowel over with ShapecCrete. Always experiment / test in a small area or sample project before attempting your final project.
ShapeCrete is easy to use. Just add water and mix.
- For Claylike consistency - Add 4 parts ShapeCrete to approximately 1 part water - Watch the Video
- For Casting or flowable consistency - Add 3 parts ShapeCrete to approximately 1 part water - Watch the Video
ShapeCrete can be poured or rolled to a thinness of ¼” and in some cases, if small enough ⅛”. It will be very hard and very delicate, like a sheet of ice. For small objects like jewelry, this thinness would not present a problem.
Take a look at the Make it Thin Video for some ideas on how to bend and curve ShapeCrete on a plastic sheet.
With regard to thickness, there's really no limit. ShapeCrete can be used to pour a countertop 2 or 3" thick, or it could be used to set a basketball pole in the ground 6' down. At some point it might make more sense to use a 5000 psi concrete mix if you're going to be casting very thick objects, but it really depends on your application.
ShapeCrete is stronger than ordinary concrete.
Using reinforcing mesh, wire, fiberglass, and rebar will vastly strengthen your projects. Simply match the scale of the reinforcing to the scale of the object being made.
These are not recommended and not needed when using ShapeCrete.
You can make objects for the backyard, like planters, stepping stones, birdhouses, and garden gnomes. Inside the home, you can make anything from functional objects, like clocks, tabletops, custom tiles, to decorative things like ribbon shaped light sconces or wall pieces. It's a great medium for making long-lasting and durable crafts and gifts. Whether you're an artist, craftsman, designer, or DIYer, you'll find something you can make with ShapeCrete that you can't do with anything else. In a pinch it can even be used for everyday concrete repairs.
Visit the How-To Video Page to get a feel for the properties of ShapeCrete. Then check out the Project Guides for Step-By-Step Instructions on how to create some of our favorite projects.
Have fun, and be sure to Share Your Project when you've made something cool!
ShapeCrete is porous, but it will hold water. If your fountain bowl is concrete, it should work for the repair. You might have bonding issues if the fountain bowl is very smooth, but if the surface is rough, it should work fine.
ShapeCrete will alter the pH of the soil. Some plants won't mind, others might. What a lot of our customers do is soak the pots in water for a week to help leach out some of that alkalinity. ShapeCrete will be rock hard in 24 hours and you should be able to add soil the next day, but you might think about wetting the piece down for a few days to leach out some of the alkalinity.
ShapeCrete will bond to any rock that has enough rough surface for it to grip. We recommend painting some acrylic bonderizer to the surface of the rock. If it is smooth rock, it would have to be roughened, and/or have some wire epoxied into holes drilled into the rock. Attach mesh to the wire, and then let the ShapeCrete envelop the mesh and rock.
Cinder blocks and bricks should be fine for adhesion but again we recommend painting some acrylic bonderizer to the surface. Also, wetting the block beforehand will allow ShapeCrete to cure properly without all the moisture being sucked out by a dry cinder block or brick. Please experiment with these ideas and try a test sample before embarking upon your final project.
