There are many recommendations on the Internet on the technique of making fillings, that is, objects "filled" or covered with epoxy resin. They mainly relate to professional products for sale, and therefore contain many requirements that are difficult to fulfill at home: the presence of a complex vacuum installation, the use of expensive hardeners, a large amount of expensive silicone, resin, etc. But epoxy fillings can be done quickly and cheaply.
"Amber" fillings. In this way, durable and durable prints and copies can be made, for example, for geological or paleontological archives. Pouring compositions provide reliable preservation of dry fragile items. It is better not to work with wet or water-containing materials, as they will continue to evaporate water in the resin, which will solidify in the form of bubbles around the sample. Because of this, at best, only part of the subject will be clearly visible, and the rest will be covered with a gray haze of steam.
The proposed technology does not require expensive components and costs, and the quality of the resulting fillings (after the first unsuccessful attempts) is slightly worse than professional ones. The sequence of actions when filling products can be as follows (for example, ED-20 + PEPA).
Product preparation. Clean the sample, rub it with alcohol (degrease), dry it, touch up or varnish (if desired) - for example, with a golden varnish.
Form preparation. In order to pour the sample into the resin, you need a container, that is, a mold. It can be made of any smooth and preferably transparent (to see the process) material. Now there is a surplus of packaging leftovers for electronics, medical and children's goods, and confectionery. They are quite suitable for working with epoxy. True, there are exceptions - this is polystyrene - brittle opaque plastic (boxes for computers and monitors are made from it), polycarbonate (DVDs are made from it), as well as PVC (used in the production of artificial leather, insulating tape, cable sheaths). The form should be wiped with a swab with alcohol and then carefully check the absence of dust, cavities, grains of sand on it. What is the shape, so will the fill.
Combining the product with the shape. So that the sample does not float when pouring the resin, it is advisable to attach it to the mold - for example, to glue (grab) to the bottom with "superglue". You can take such a form in which the sample would fit tightly. Another option is to support the floating sample (if lighter than resin) with a wire or glass rod. In this case, you need to have time to pull it out until it solidifies completely. The glass rod can be left in the product and broken off - the refraction of the glass is comparable to the resin and the rod will not be visible there. And if a wire is used, it can play a role, for example, a keychain chain. By the way, glass will help save resin, for example, it can be placed on top of a freshly poured sample, thereby forming the upper "crust" of the product. Glass is perfectly compatible with epoxy, and visibility through it will be even better than through polymer.
Preparing the resin. Mix the resin with the hardener according to the instructions. It is better to knead the resin for at least five minutes, avoiding the appearance of multiple bubbles (they may remain in the final product). If they do appear, you can put the mixture in a warm place for one or two minutes (but not more).
Pouring progress. Carefully pour the prepared mixture of resin and hardener into the mold with the product. Alternatively, you can pour a little resin into the mold, and then insert the product. The form must be left in a dry warm place for at least a day. After curing, cut the mold, for example, with a clerical knife (carefully so as not to scratch the resulting fill) and remove.
Opaque, highly filled composite fillings. If it is necessary to obtain not a transparent fill, but only a polymer (or gypsum) copy of the sample, a cheaper version of an epoxy composition filled with 65-80 wt% sand, gypsum, cement and other cheap powders is used. For work, you need a model plasticine (it can be replaced with an ordinary one, but it will stick to the product more strongly), lubricant (silicone or even sunflower oil) for a disposable form, ED-20 resin, PEPA hardener (sold complete with resin), microfillers ( gypsum, sand, cement, flour) and macro fillers (stones, strings, wire). Professional modelers use special silicones instead of plasticine, but they are expensive.
The procedure can be as follows:
Form preparation. Model plasticine (or silicone mold) is kneaded, heated, etc. in the required amount and half of the lubricated sample is pressed into it (in the classical version). Often, however, it is more profitable to press in the sample by about two-thirds, then the main details of the print (for example, the head, hands, fine patterns) will be almost ready the next day. A second mold is prepared for the rest of the sample. After a day, the hardened print should be carefully aligned with the second mold, which printed the rest of the sample. Forms after seizure
the sample should be re-coated with a separator - vegetable or silicone oil.
Composite preparation. It is recommended to add components to the resin in the following order: plasticizer, pigments, fillers, hardener. Before adding components to it, the resin can be warmed up (in a water bath, radiator, etc.) - for the convenience of stirring. After the introduction of the hardener, it is no longer possible to warm up the composition, since it can harden too quickly or even "boil" instantly. The epoxy curing reaction is exothermic (that is, with self-heating), and, according to the laws of thermodynamics, additional heating will shift the equilibrium towards the acceleration of the reaction.
The components should be mixed in 5-6 minutes. The consistency of the composite should be viscous (like sour cream) - such that the composition remains on the vertical walls of the mold without additional reinforcement. Too liquid composite will flow to the center (bottom) of the mold, and the fragments of the product will not be fully formed. Composite that is too thick will prevent thin parts from forming. The composition is suitable for work within one hour, after which its viscosity will begin to increase and it will be more and more difficult to work with it.
Filling and laying is carried out using a glass or a spatula. For economical consumption of epoxy, one-piece pouring is done only for the loaded elements of the product, for example, for the paws of a toy animal or thin partitions in a part. The walls of the mold are lined ** with the working compound until the mold is completely coated, after which a reinforcement, such as glass or cotton fiber, is glued in in places where the mass is potentially draining.
Toys can be made from epoxy. Using filling (gypsum, chalk, sand, etc.), 4-5 ml of resin is enough to make a full-fledged toy weighing 10-12 g and measuring 10x5 cm. A simple calculation shows that in this way as many as 200 soldiers can be obtained from one liter of resin , animals, pupae and their cost will be 15-25 times less than those bought in the store.