Table from slab and epoxy resin
Table from slab and epoxy resin. So, let’s leave any preface like what is epoxy resin and about how furniture made of epoxy and wood have long been an absolute trend all over the world and turn directly to the question “how to do it”, i.e. we need instructions.
For example, consider a countertop which is a cross-section of the rhizome or slab.
The first thing we need … no, not slab or tar. In the beginning, the idea itself should be born, as well as the image of what this table will be (or whatever else) and even if it turns out not quite as expected, in any case, what you create will be in a single copy and if it is not a masterpiece, then it is certainly exclusive.
Let’s highlight several stages in our process.
1. Choice of epoxy resin
2. Selection and processing of wood
3. Preparing the formwork
4. Laying of countertop parts
5. Mixing and filling
6. Formwork removal and sanding
7. Finishing the finish layer
1. Choice of epoxy resin.
The choice of resins is quite wide, I will not advertise this or that brand here, I will only say the main points.
The epoxy should be chosen based on what result you want to achieve.
When choosing a resin for casting a countertop, pay attention to the following properties::
– low viscosity
– saving the volume after filling
That is, the resin must be sufficiently fluid to be easily poured into the mold.The use of such resin ensures that all small cracks and hard-to-reach places will be closed. This is also important because when mixing and pouring, air bubbles may appear, which will be more difficult to get rid of the higher the viscosity of the resin.Mixing the components, if necessary, you can add your own color pigment to create, for example, the effect of the “river table” or just give color. In addition to the resin for casting (let’s call it basic), we will need a varnish for coating, that is, sealing the countertop.
Once your epoxy table is cast and cured, it is highly advisable to apply a final clear coating to the countertop as a protective layer. This seals the epoxy and increases its durability. When choosing such resins or lacquers, pay attention to the UV resistance, so that this transparent layer does not turn yellow over time.
Another important point. When choosing a resin, always pay attention to the recommended filling thickness, otherwise there is a risk of boiling the resin. Follow the technology specified in the instructions for the material. Therefore, it is important to know the dimensions of the future product in advance.
Now let’s move on to the process:
First you need to calculate the amount of resin we need. Here everything is simple. If the table is rectangular, multiply the length by the width and by the height V=H3. If round – the number pi (3.1415) is multiplied by the radius and by the height V= πr2h. All measurements are made in cm. The result is in cm3. but we need it in liters. Here it is even easier 1l = 1000sm3. But there is one thing. All these calculations are valid only in order to find out the total volume of the product.
How to find out the volume of the resin itself in a table top made of resin and slab or other bases. There is a simple way. When the countertop formwork is ready, put the wood in it and fill it with something loose, such as rice (no matter), this will be the approximate amount of resin required.
2. Selection and processing of wood.
The second important step in creating a countertop is the selection and preparation of wood.
I will say right away not all wood species have the same characteristics and some of them are more suitable than others for an epoxy table. For example, some types of wood are more porous than others and will tend to “drink” the resin during pouring and release air bubbles, which is not good.
It is preferable to use such types of wood as maple, hazel, elm, olive. It is not recommended to use more porous wood, such as pine. You can paint the wood with a stain to highlight the texture and better contrast with the colored epoxy fill. Most often, wood is used from the root and base of the trunk in cross-section.
But, choosing the right shape, pattern, thickness and color of wood, only half the case. After a while, our product may begin to collapse due to the fact that the tree has deformed. And the reason for this is poor preparation of the material.
The basic rule is that the wood must be properly dried, which is impossible to achieve at home. To dry wood of joiner’s quality, a certain temperature is necessary. In the ideal solid wood to be dried in the following way:
After the tree is cut, it is left for storage for a period of six months to two years.
When the moisture content of the wood is reduced to a minimum, start cutting. Here the task is to reveal the most interesting and beautiful sides of the array.
Finished slabs are kept in moderate atmospheric drying as long as possible, the longer the wood stands, the better the result will be. This is necessary in order to complete all biological processes in the tree, otherwise there will be internal stress, which will lead to deformation and the appearance of cracks.
The last stage is industrial drying. The wood should dry to a joiner’s humidity of 8-12%. It is also impossible to over-dry, because such a tree will eventually begin to absorb moisture again and change its shape.
Having the wood ready for processing, you can start leveling the surface. If you got a perfectly smooth slab, which can not be, you can skip this step. So, we will need a milling machine or just a table, a manual milling machine and a carriage for the milling machine.
It will not be difficult to assemble such a structure. The principle of operation is the same, but if you want to learn more about the methods of milling slabs in this way, you can find a bunch of videos on the web.
After milling, the wood is processed by a grinder with abrasive nozzles of different grain sizes, the higher the number of grains, the finer the abrasive. Let’s start with the number 150 abrasive, then move on to 240, 360, 400, 600, 800, 1000, 1500 and higher.
The last treatment is already polishing. Here you can already apply a polishing paste and a foam or felt disc. Fine polishing is not always necessary, but it is necessary for individual products.
The next step is cleaning and processing the slab. Remove the bark and sand the surface. To get rid of sanding residue and dust, blow with compressed air or use a brush. Wood is a porous material that has cavities and cracks.
When coated with epoxy, it often releases air in the form of bubbles. To prevent the formation and sticking of bubbles in the epoxy casting during its solidification, all wood is applied with a primer. To do this, you can use a water-based varnish or a water-soluble multi-purpose epoxy resin. Thoroughly soak each area, this will prevent leaks through cracks and cracks in the wood.
Also at this stage, we can apply a tinted stain to give the product a more saturated tone.
3. Preparation of the formwork.
It is quite simple to assemble such a structure. For the base (bottom side) and frame (sides), an MDF board or laminated chipboard is suitable. The frame can be made from wooden bars or also from MDF or chipboard.
It is important to observe the exact dimensions and avoid any subsequent resin leaks. The sides should be about 15 mm higher than the actual surface of your future countertop. To connect the side panels to the underside, it is best to use self-tapping screws, and for sealing, pre-apply a regular sanitary silicone sealant. Do not forget to remove any excess sealant after drying.
Now about one more property of resin-adhesion.
It is important to understand that simply removing the product from the mold after solidification without damaging it is an almost impossible task. Therefore, when the formwork is ready, before laying wood or other components and pouring, treat the walls of the formwork with a separating compound, the material from which the resin will easily peel off.
Use silicone lubricants, oil-containing and wax lubricants, or vaseline. A good option is a silicone or Teflon spray. Applying it to the mold in several layers (until a smooth surface is obtained) can also counteract excessive adhesion.
You can lubricate the mold with ordinary oil, but first it is better to check how the resin will react to this oil to avoid unpleasant surprises.
And the last important point before filling is to put our design horizontally. Level to help you.
4. Laying table top parts.
Before laying the wood in the formwork, fill a small layer of resin, about 5 mm., this will prevent the formation of air pockets. Lay the slab and, as it were, tamp it, then fix it so that the tree does not float after pouring.
5. Blending and filling.
When working with resin, be sure to wear gloves, safety glasses ,and respiratory protection.
Use a large enough bucket to mix the resin. It is best to use a bucket large enough for the entire amount of resin or the first layer, depending on the technology and type of resin (if you need to fill the resin in layers). This is due to the fact that the resin tends to get very hot and boil at a certain thickness.
During the mixing phase, you will notice that epoxy is one of the most sensitive materials. If a certain level of filling of the container or a certain total amount is exceeded, the mixed mixture can become very hot due to the exothermic nature of the chemical reaction.
If the resin boils, it will immediately become unusable or become cloudy. In any case, pay attention to the maximum thickness of the layer (see the manufacturer’s instructions). Some types of resins can be cast in a single step.
Make sure that you adhere to the mixing ratio recommended by the manufacturer and that the resin components mix very well. It is best to use a drill with a mixer. Mix at low speeds. This is the only way to ensure optimal mixing of the components.
If air bubbles form in the resin during mixing, they can be removed with a heat gun or a conventional hair dryer . Try to use as much heat as necessary to make the air bubbles rise in the material. Otherwise, overheating of the resin can have a very negative impact on the quality.
Carefully pour the epoxy in a thin stream. Do not rush, when in a hurry, air bubbles are formed, which will not show themselves in the best way when grinding. And do not forget to cover everything later, in order to avoid getting dust on the uncured resin.
Drying (polymerization) of epoxy resin is carried out on average per day. Optimal solidification is achieved after 14 days.
Let me remind you that to achieve the best result, observe the accuracy in the proportions when mixing the components of the epoxy resin. Read the instructions carefully.
6. Removing the formwork and sanding.
Next, the cast countertop is removed from the mold. To do this, remove all screws, clamps and carefully release the countertop from the mold with a chisel and a plastic hammer.
If desired, you can also perfectly smooth the edges of your countertop with a milling cutter before sanding.
Tip: The epoxy resin should be really dry before sanding. Therefore, you must wait at least 48 hours before processing. Follow the manufacturer’s instructions, as there are resins that take even longer to fully harden.
Once you have removed the product from the mold, it’s time to sand the countertop.
There are several types of grinding, of which two main types can be distinguished: dry grinding and wet grinding.
Wet grinding of epoxy resin with water-resistant sandpaper is more effective than dry grinding. And there are several reasons for this. First, the abrasive paper is much less clogged when wet grinding and therefore lasts much longer. Small irregularities are removed directly during the grinding process, and you immediately see the result. In addition, the amount of dust produced is much smaller.
However, there are cases when dry grinding is more suitable. For example, if you want to combine a piece of epoxy resin with wood or other materials that are sensitive to moisture. Wet sanding will cause the wood to swell and produce unsightly stains.
But there are reasons why wet sanding is better than dry sanding. One of these reasons is that when dry grinding with epoxy resin, whether with an eccentric grinder or by hand, very strong heat is released. This heat can cause the resin to dissolve and the surface to become opaque. In this case, it is almost impossible to give the surface a beautiful shine again.
Therefore, if you are working with a product exclusively made of resin, then you should choose wet grinding to be safe. Because at the same time, much less heat is released. In addition, dry grinding of the epoxy resin produces a lot of dust. If you decide to use this method, you should always wear a mask, as epoxy dust is considered carcinogenic.
Since our countertop includes wood elements, we will use dry sanding.
For dry sanding, we recommend using an eccentric sander.
To protect your health, you must wear a respiratory mask during dry grinding. Only then can you be sure that you will not accidentally inhale toxic dust. Ideally, you should choose a well-ventilated room for your work.
Start with a grain size of 120, gradually increasing the grain size to at least 1000. When dry sanding, the sandpaper will clog very quickly, in this case, you can easily remove the remaining resin from the surface of the sandpaper with a special brush.
If you have changed the grain size, carefully remove traces of the previous grain size.
The Council: You will get a really beautiful shiny surface of the epoxy resin part only if you polish the part with a grain size up to 1000. With” normal ” grinding with epoxy resin, you will get at best only a very light shine.
7. Finishing of the finishing layer.
At the end of the process, you can treat the polished surface of the wood with a special oil or wax. Our countertop is ready.
The selection of oil or wax is an important point. The composition will give an additional tone to the tree, this should be taken into account.
But you can move on to the next coverage. This will be a protective layer. We use at this stage a polyurethane varnish for resin products. This varnish prevents the destruction of the material from exposure to ultraviolet light, protects against physical exposure and, importantly, does not turn yellow over time.
For better adhesion, the surface must be dry and clean, free of grease, dust, wax, varnish and polishes. Pre-polish the surface. Use a sanding nozzle. Remove the dust with a damp cloth and allow the surface to dry.
Detailed technology of working with varnish is specified in the instructions.