How to make ballistics gel
Techical note: This is only word to word translate.
Ballistic gel is a material similar to gelatin, which has similar characteristics as living tissue, in terms of density and elasticity. It is used in ballistic testing arms, stabbing and cutting weapons. The tests are an indicator of efficiency not only in developing new weapons, but mainly help in the reconstruction of replica weapons in ancient times experimental archeology.
Ballistic gel is essentially concentrated gelatin. There are two main types of gelatin:
- Agar : a plant origin. It is based on extracts from marine algae. In addition to gelatin cakes and pies are used for the cultivation of bacterial colonies.
- Edible Gelatin : obtained from pig skins and bones. It can be found in jelly soup, pudding and similar foods.
Rubber-like teddy bears and candy in addition to few exceptions, produced from glucose syrup.
Ballistic gel can therefore also produce at home. Use pork gelatin. To get the solid mass, the recommended ratio is 8 ml of water to 1 g powdered gelatin. For simplicity, we can keep the right balance is automatically calculated in the table below.
Process for the production of ballistic gel pork gelatin
Depending on the size container you calculate the correct ratio of water and powder. Each bag usually contains 20 grams of powder. I purposely chose a container that has a cap. If the mixture gets into the dust begins to deteriorate rapidly.
| Automatic calculation of the amount of water and powder | |
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Help: Values a, b, c are the dimensions of the container in centimeters. Dimension c put the amount of container, but a forecast of the level of liquid gel. Leave space to be able to gel a little, stir well to mix.Decimal numbers use a dot instead of comma. |
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Powder to sprinkle water gently, so as not to create bubbles.
Mixture gently and slowly stir, so we there nevniesli bubbles. Mixture was allowed to swell 30 min.
Meanwhile, prepare a second container, wipe it with oil.
Oil really just a few drops. To prevent sticking on the wall.
Let the pot boil water. Turn off gas and a container of warm water to dive.
Gently beating until gelatin is completely dissolved. If the liquid gel is still a lot of bubbles use of narrow-necked container and vacuum pump air odsajeme. The easiest way is to pour it into bottles and normally aspirated air through the mouth. Lowering the pressure bubbles float to the surface.
After complete dissolution, pour liquid gel into a greased bowl. Moreover, oil babble on the surface of thin film that prevents foaming. Liquid gel allowed to cool to room temperature. Then put the bowl in the refrigerator 24 hours. The refrigerator is Nepraš, containers should be kept open, otherwise the inside of mist.
The finished product has the consistency of rubber. Next time I'll try anything in life size.
Test gel materials
The scene. The building must be properly illumination.
I put a gel cube on a wooden board. I shot an arrow perpendicular to the plate from top to bottom, from about one meter. The strength of the bow is about 15 lbs. Scale used to determine the speed of a flying arrow. Dark blocks are spaced one centimeter.
Ballistic gel must be so tough that it deflected the ball from the Airsoft guns.
Ballistic tests of wooden arrows
Šíp s listovým kovovým hrotom.
Arrow Natural maple wand. Tip of the squadron are bonded to natural bone glue. The tip is cut out of his tip sheet thinned by cold forging. I sharpened edges on both sides. Feathers of the pigeon. Production used arrows and bows in a separate article describes how to make a bow .
Plate metal tip part 1
Plate metal tip part 2
Arrow flew a thin layer of gel and stuck into a wooden board. Tip of the arrow is released and ceased. In view of the effectiveness of weapons that can be considered an advantage. Flat tip leaves a wound 15 mm wide across the diameter. Kynetická energy pushing the blade through the material.
Arrow without a tip
Sharpened wooden arrow without a tip.
I missed the bit is out of focus.
Arrows without spikes were used even before man discovered stone, bone and metal spikes. Even in the later period were used to tip arrows without hunting. The video is seen as an arrow flies gel and is reflected from the wooden base plate. Leaves behind a thin close the wound.
Odometry flying arrow
Geometric vyjadrejie speed. Click to enlarge.
To calculate the speed I used images of high-speed camera. Recording speed was 1000 fps. In the picture above are two consecutive images with an interval of 0,001 seconds. Since the fence is a little askew I made parallel with the edge (red line). Track down the real difference intersections of red and yellow lines (marked with rings). Software I have measured a 29.51 millimeters.
measured speed at impact is about 30 m / s which is the equivalent of 100 km / h
If speed is equal to the runway in [millimeters] and time [milliseconds], the measured value is equal in meters per second. The measured velocity is very questionable, because the images are blurry and small resolution. I shot an arrow into the earth from the mountain, which is not natural at all. The second shot is the tip of the already partially buried in the gel. The target of the gel was too small, in the future, do something in life size and will shoot horizontally.
Where to go?
How to make a bow - The production of wooden bow and arrow, which was used in this test.