The title of the article is about a chair, but it will be about a stool made with your own hands using the technology of casting parts from epoxy resin. The difference is in the number of legs.
We will make a three-legged stool. The 4 points of the legs of a classic chair are much more difficult to align along the plane for their simultaneous fit to the floor, so that the product does not limp and does not jump on the floor when trying to sit on it. A seat with three legs is deprived of this disadvantage initially, even if the floor is not a flat plane and there are height differences on it.
To make a designer chair / stool, you will need:
- Epoxy resin complete with hardener.
- High–quality pruning of thick branches with intact bark – an arbitrary amount. 3-4 of them should be straight and long enough to make legs for the product. The length of the leg is selected so that the distance from the upper plane to the lower point of the leg is within the standard height of the chair for an adult.
- Cutting wood (veneer, planks) with neat cuts of arbitrary shape.
- Polyethylene – it covers the surface of the table / workbench on which the polymerization process of epoxy resin will take place. It is needed to protect the surface of the table. Drops, splashes of frozen epoxy are almost impossible to remove.
- An old plastic bucket with a round or oval bottom, or an unnecessary plastic canister with a 4-carbon section – for making the shape of the future seat.
Additionally, you can prepare a transparent dye for polyester and epoxy resins. If there is an idea to paint the mass of epoxy in some color. All kinds of small fillers: beads, cosmetic sequins and other small components introduced into a liquid mass of epoxy resin to increase decorative effect.
Fixtures and tools
To work, you will need:
- Saw (suitable and manual).
- Level (required!).
- Grinding machine.
- Plastic spatula (preferably disposable).
- A work suit that does not give lint, a cap for hair. This is necessary to prevent foreign inclusions from entering the solidifying surface of the epoxy.
The room should be well ventilated. Ideally, you need a hood, a workshop with a hood (cube). Epoxy resins emit harmful substances (formaldehyde, phenols) during solidification.
Such harmful substances are released by polyester resin and some other compositions for pouring. For example, epoxy-phenolic, unused in the manufacture of furniture.
In fact, epoxy resin does not emit substances into the air even in liquid form, a respirator and gloves when working with it are needed so that it does not fall into the form of microscopic droplets inside when breathing and on the skin.
The order of work
The order may be arbitrary, but it is better to plan the stages of work and follow them. In order not to get confused in materials, tools and sequence of actions.
- The bottom (or a flat sidewall from the canister) is cut off from the plastic container along a carefully drawn line. Then another line is measured higher, at a distance equal to the thickness of the future seat. An incision is made along this line. We get a ring, an oval ribbon, a closed rectangle with rounded corners – the shape and size of the stool seat.
- A fiberboard sheet slightly larger than the planned casting is placed on the table (workbench). It is checked by the level, if necessary, they achieve a perfectly horizontal plane. This is done so that the epoxy resin does not gather more in one place than in another due to the slope of the surface, and the thickness of the stool seat is the same in all directions. FIBERBOARD is glued butt–to-butt with double-sided adhesive tape – for ease of separation after the epoxy has solidified.
You need a regular, one-sided tape. When using double-sided tape, it will be problematic to tear off the hardened workpiece from the formwork.
- A mold for filling is placed on the adhesive-taped surface of the leveled fiberboard. From the outside, the gap between the glued fiberboard and the adjacent edge of the mold is sealed with hot glue so that the epoxy resin poured into the mold does not leak out.
Sealing is more reliable to produce conventional silicone for plumbing and construction work.
- From branches of different diameters, three (or 4 – for a 4-legged chair / stool) branches of approximately the same diameter are selected for the legs and from 3 – to fill the volume of the form. Roundels are filed for laying in a mold.
- Gasoline (aviation or for lighters) degreases the surface of the mold, wooden roundels and other fillers, the surface of the part of the legs that will be sunk into the seat.
- Legs are installed – double-sided tape is useful for this. Roundels from branches of different diameters are closely stacked in a pre-selected order. They will also serve as a decorative element. Try different options for laying roundels, try to combine them and geometrically sawn boards and veneer trimmings. The criterion is only your sense of beauty, and even the originality of the resulting composition.
- To ensure that the future legs retain their position and do not go to the sides, connect their ends, which will then stand on the floor, temporarily with light wooden slats, creating a relatively rigid frame.
Filling the form
If it is decided to leave the resin transparent and not colored in the mass, pour the hardener into the epoxy resin in the proportion specified in the instructions. The lack of a hardener will cause too slow polymerization, when instead of a day or two you will have to wait twice or three times longer. It is not a fact that it will freeze to the end, and the frozen mass will stick to your hands for a long time. An overabundance of the hardener will cause a sharp rise in the temperature of the reaction taking place. The mass may boil with the formation of bubbles, which will hopelessly spoil the business started.
Important! The temperature can rise not only from an overabundance of hardener. It may also depend on the shape of the vessel in which the resin and the hardener are pre-mixed.
The larger the overall dimensions of such a vessel are close to a ball or cube, the greater the likelihood of spontaneous boiling of the mixture. This is especially true of epoxy resins, where amines are used as a hardener. Therefore, the diluted mass should be poured into the mold as soon as possible. By changing the distribution configuration in space.
During this period of time, ventilation of the room where the work is carried out is very important: it is during pouring and at the initial stage of cooling that a maximum of aldehydes and phenols, very harmful to health, are released from the polymerized mixture.
If it was decided to color the epoxy in the mass, then the dye for it should be introduced after or during the time when the bulk of the substance is mixed with the hardener, but not before.
It is better to introduce dyes after mixing the resin with the hardener.
How to achieve stability on 4 legs
In order for a four-legged chair or stool to come out not lame, before pouring epoxy into the form of a seat, it is easiest to align all future 4 points of fit to the floor on the same plane.
Attach to these points a segment of a very rigid and flat plane made of chipboard, fiberboard or thick even plywood. And fix them in this position until the very end of the hardening of the epoxy resin poured into the mold.
The minimum solidification time is 24 hours. It is better not to rush things, to let the polymerization process go through to the end, before the last molecular chains are included in the process. It may take 48 hours to do this.
After that, you will need to make some effort to tear off:
- The surface of the future seat from a layer of adhesive tape glued to the fiberboard.
- Plastic shape from the end of the seat.
The second will be impossible without cutting the sidewall of the mold, after which it is relatively easily separated from the casting.
Bringing into “marketable form”
The surface of the frozen resin will be slightly heterogeneous due to the irregularities of the matrix and traces of adhesive tape. You will need to grind the surface with a grinder.
Just don’t get carried away, change the skin in time for an increasingly smaller one. Otherwise, you will remove it with such force that the epoxy-filled wood of roundels and filler dies will be exposed.
But it will still not be possible to achieve glossy surfaces by grinding with a skin. It will be somewhat matte. Therefore, after grinding and turning the sharp edges of the seat, it is advisable to dilute a small amount of epoxy resin again and smear it on the outer and side surfaces of the seat with a spatula.
Having previously placed a chair / stool on a surface covered with polyethylene, so that it is not spoiled by accidentally dripping drops, having previously strengthened the canopy on top, protecting it from dust and specks.
Attention! During grinding (especially if you have a rotating, circular grinder), there is some heating of the surface. Which provokes the release of additional portions of aldehydes and phenols. In addition, the dust generated during grinding is extremely harmful to health. Therefore, it is advisable to supplement the work suit with protective glasses and a respirator. Or at least a thick cotton-gauze bandage.
Hazards for the release of harmful substances relate to polyester resins and some other compositions for fillings. The epoxy resin, after complete curing, is completely inert under normal conditions. It does not emit any harmful substances. Including during machining and heating to significant temperatures. Inhaling its dust is no more dangerous than inhaling sand, although it requires protection with a respirator.
If branches in the bark are used for the legs, then sooner or later it may fly away from the wood as a result of over-drying and mechanical influences. Therefore, before fixing such legs in the thickness of the epoxy, you can pre–dilute a small amount of it and smear the surface of these future legs with it – which will significantly increase their mechanical strength.
For active impregnation of the bark up to the wood itself, after coating with a layer of epoxy resin, it is possible to dry the blanks in a large oven, which will speed up the resin polymerization process.
If the chair or stool you made pleased you and others, and for completeness the headset will be willing to do more, try to maintain the stylistic unity by making the following similar to the first, only better.