ARTICLES


I. Bahan-Bahan Dasar Pembuatan Fiberglass 

Resin
Resin adalah bahan kimia yang berbentuk cair, menyerupai minyak goreng, tetapi agak kental. Jenis resin bermacam-macam. Untuk bahan aksesoris fiberglass, umumnya menggunakan resin bening atau resin butek. Resin bening, biasanya digunakan untuk bentuk yang menonjolkan kebeningannya, seperti untuk aksesoris visor, kap lampu dll sebagai pengganti mika, namun penggunaan resin bening yang ada dipasaran untuk pengganti mika, masih belum menghasilkan kualitas yang memuaskan. Sedangkan resin jenis butek lebih banyak digunakan untuk pembuatan aksesoris, disamping harganya murah, resin ini dapat dengan mudah dibeli di toko-toko kimia.

Katalis
Cairan ini bisa dibilang pendamping setia resin, cairan ini biasanya berwarna bening dan berbau agak sengak. Cairan ini berfungsi untuk mempercepat proses pengerasan adonan fiber, semakin banyak katalis maka akan semakin cepat adonan mengeras tetapi hasilnya kurang bagus. Cairan ini jika mengenai kulit akan terasa panas, seperti cairan air zuur.

Kalsium Karbonat
Bahan berbentuk bubuk putih yang menyerupai terigu ini berfungsi sebagai pengental adonan fiberglass utama (resin, katalis dll). Semakin banyak campuran Kalsium Karbonat pada adonan, maka hasil fiberglass akan menjadi lebih tebal dan berat. Bahan ini dapat diganti dengan Talc, tetapi warna Talc agak lebih gelap. Tetapi saya belum menemukan perbedaan yang signifikan penggunaan Talc & Kalsium Karbonat.

Met/Matt
Met merupakan bahan serat kaca. Bahan ini berfungsi sebagai serat penguat dari adonan fiberglass ketika akan dicetak, agar hasilnya menjadi lebih kuat dan tidak mudah pecah. Bentuk met bermacam-macam, ada yang mirip bihun, kain, karung dan sarang lebah. Tetapi yang banyak dijumpai dipasaran adalah yang berbentuk seperti bihun.

Kobalt (Cobalt Blue)
Kobalt adalah bahan kimia yang berbentuk cair, berwarna biru mirip tinta dan mempunyai aroma tidak sedap. Cairan ini digunakan untuk tambahan campuran adonan resin & katalis, agar adonan lebih merekat pada met dan mempercepat pengerasan adonan fiber. Terlalu banyak menambahkan Kobalt dapat mengakibatkan hasil fiber yang getas (rapuh).

Wax (Mold Release)
Bahan ini sepintas mirip mentega/keju ketika masih di dalam wadahnya. Berfungsi sebagai pelicin pada tahap pencetakan yang menggunakan mal/molding, agar antara molding dengan hasil cetakan tidak saling merekat, sehingga dengan mudah dapat dilepaskan.


CLAY 
Clay is a fine-grained soil that combines one or more clay minerals with traces of metal oxides and organic matter. Geologic clay depositsare mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.

Clays are distinguished from other fine-grained soils by differences in size and mineralogy. Silts, which are fine-grained soils that do not include clay minerals, tend to have larger particle sizes than clays, but there is some overlap in both particle size and other physical properties, and there are many naturally occurring deposits which include silts and also clay. The distinction between silt and clay varies by discipline. Geologists and soil scientists usually consider the separation to occur at a particle size of 2 µm (clays being finer than silts),sedimentologists often use 4-5 μm, and colloid chemists use 1 μm. Geotechnical engineers distinguish between silts and clays based on the plasticity properties of the soil, as measured by the soils' Atterberg Limits. ISO 14688 grades clay particles as being smaller than 2 μm and silts larger.

CERAMIC CLAY
Ceramic clays are water-based substances made from clay minerals mixed with other raw materials. They are baked at high temperatures, in a process known as firing to create ceramics, such as terra cotta, earthenware, stoneware, and porcelain. Paper clay produced by pottery clay manufacturers is any of these clay bodies, to which a small percentage of processed cellulose fiber has been added. When kiln fired, the paper burns out, leaving the clay body. Consequently the firing temperatures and glazes selection should be the same on those used with the clay body.

OIL BASED CLAY
Oil-based clays are made from various combinations of oils, waxes, and clay minerals. Because the oils do not evaporate as does water, oil-based clays remain malleable even when left for long periods in dry environments. Articles made from oil-based clays cannot be fired, and therefore are not ceramics. Because the viscosity of oils decreases as temperature rises, the malleability is influenced by heating or cooling the clay. Oil-based clay is not soluble in water. It can be re-used and so is a popular material for animation artists who need to bend and move their models. It is available in a multitude of colours and is non-toxic.

Oil-based clays are referred to by a number of genericized trademarks. Plastilin, was patented in Germany by Franz Kolb in 1880. Plasteline was developed by Claude Chavant in 1892, and trademarked in 1927. Plasticine was invented in 1897 by William Harbutt of Bathampton, England.Plastilina is trademarked as Roma Plastilina by Sculpture House, Inc. According to their website, their formula is 100 years old. Roma Plastilina contains sulfur, and since certain moldmaking compounds will not set in sulfur's presence, this brings difficulty to making molds of items made of itIndustrial plasticine.
"Peacock" modelling clay is available and widely used by sculptors and animation artists in India. This does not contain sulphur and is non-toxic.

Being readily worked in fine detail, oil-based clays are also suitable for the creation of detailed sculptures from which a mold can be made. Castingsand reproductions in a much more durable material can then be produced. Cars and airplanes may be created using industrial design-grade modeling clay.

POLYMER CLAY
Polymer clay is a modeling material that cures when heated from 265 °F (129 °C) to 275 °F (135 °C) for 15 minutes per 1⁄4 inch (6.4 mm) of thickness, and does not significantly shrink or change shape during the process. Despite being called "clay", it generally contains no clay minerals. Polymer clay is sold in craft, hobby and art stores, and is used by artists, hobbyists, and children. Polymer clay is also popular in animation since it allows static forms to be manipulated frame after frame. Leading brands of polymer clay include Fimo, Kato Polyclay, Sculpey, & Modello.

PAPER CLAY
There are two major groups of paper clay/paperclay users: those using paperclay as an unfired body predominately for recreational use or doll making, and those using paper clay in the ceramic art studio to make sculptural and functional studio pottery.
Commercial air drying paperclay does not shrink noticeably when drying. Paperclays are cellulose based substances which air dry firm. The finished sculpture is extremely lightweight.
Paper clay is hand made or commercially available clay to which a small percentage of processed cellulose fibre is added, to increase the tensile strength of dry clay, enable dry to dry and soft (wet) to dry joins.

[ souce : wikipedia.org ]

No comments:

Post a comment