Tip 1: How to make fiberglass

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Tip 1: How to make fiberglass

Fiberglass plastic every day to become more popular. It is used during the production of boats, cars, accessories, windows, etc. It has a number of advantages. In addition, it's not so difficult to make yourself.

You will need

glass mat, fiberglass, hardener, polyester resin, catalyst, matrix gelcoat, wax.

Instructions

Layout. You can do without it, but you will definitely lose quality. Use instead of the layout spacers, which then put the fiberglass. The model can be made of such materials - foam, plasticine, plywood, etc. The layout must be smooth and exactly repeat the part you need.

Make a matrix. According to the technology, you need to completely cover the layout with a layer of wax and polish it. After that, apply a matrix gelcoat on its surface. It is thicker, it is necessary to apply a thin layer, so it is much easier to lay down than an ordinary one. The resulting gelcoat base makes it possible to achieve an ideal matrix surface. Apply it manually with a special sprayer or brush. Gelcoat helps to form the outer surface of a product made of fiberglass.

Manufacture fiberglass. From the very beginning, place the cut glass material into the fabricated matrix: glass mat, glass fiber cloth or other type of filler. Choose it, based on the requirements that are imposed on the future product of fiberglass. After that, using a brush or soft roller, glass fiber cloth or glass mat impregnate with a binder mixture - hardener or polyester resin. In fact, GRP is a special composite material, which consists of hardener, polyester resin, glass mat or fiberglass.

Traction. This is the last stage. Pull the laminate (not hardened fiberglass) with a rigid roller. The goal is to completely remove air bubbles from it. After curing, remove the finished product from the mold. Expose it to special machining: cut the cob - cured polyester resin or excess fiberglass around the edges of the product. If necessary, drill holes.

Tip 2: What is a crossbow

In the whole history of mankind was inventedmany types of weapons. One of them is a crossbow. This mechanical propelling device significantly exceeds in its combat characteristics of its predecessor - the usual bow. The crossbow was so effective weapon that in a number of armies it is used till now.

Crossbow - improved bow

Crossbow is a special kind of coldweapons, capable of shooting a considerable distance. This is a mechanical bow designed for throwing arrows. By its lethal force and accuracy of shooting, the crossbow was significantly superior to the traditional bow, although at first it lost to it in the rate of fire. The most active crossbows were used in medieval wars. The arrow, released from such weapons from a few tens of meters, through and through struck the warhorse along with the rider. For shooting from the crossbow, arrows of a special design were used, which seem shorter and thicker than usual. In the war and hunting, hand-type crossbows were used, but some versions of this weapon were widely used as combat vehicles.

Large in size crossbows in antiquity were called ballista.

The first crossbows were simple in theirdesign, so making them was easy enough. Only later did these weapons become more complex. There were new types of crossbow bows, which had a complex lamellar composition. For the convenience of loading, the crossbow was supplied with special tensioning mechanisms, which greatly facilitated the work with the weapon. To tighten the bowstring, it was enough to scroll a special handle several times.

The device of a crossbow

The base of any crossbow is the bow or shoulders. Previously, this element was made of solid wood. Modern sports and combat crossbows are made of more suitable materials. In the course is steel, fiberglass, carbon, composite materials with high strength characteristics. Onions can be straight or arched. The ends of the bow are equipped with attachments for the attachment of the bowstring. The arms of the crossbow are attached to the box, which gives the crossbow the appearance of modern small arms. The bed provides an opportunity to hold weapons in their hands and aim. The usual material for making this element is natural wood, such as walnut, beech or oak. Modern models of crossbows have a bed of plastic. In the upper part of the case there are boom guides. At the back of the bed is equipped with a butt.

In front of the old crossbows you can see a stirrup - a leg brace, designed to hold the weapon when it is loaded.

An important part of the crossbow is the trigger,called the lock. It is designed for heavy load and withstands strong tension of the bowstring. The reliability of the trigger device depends not only on the effectiveness of the shooting, but also on the safety when handling weapons.