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Rare Earth Magnetic Grates Purify Raw Clay Material

October 17, 2018
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Eriez grate magnet
Eriez grate magnet
Hopkins cups
Hopkins cups
Hopper with magnet
Hopper with magnet
Magnet with iron spots
Magnet with iron spots

When it comes to making intricate pottery pieces for a loyal base of customers, Bryan Hopkins is a perfectionist. As the owner of Hopkins Pottery — based in a renovated building in Buffalo, NY — Hopkins has been creating eye-catching artwork for more than 20 years, all the while perfecting his craft and techniques.

From his 600-sq-ft studio with a built-in kiln, Hopkins creates about 50 pieces a month for customers, craft shows, and exhibits. The majority of the pieces are made from porcelain, which Hopkins has been producing from scratch for five years because of his need for pure product.

In his quest for perfection, Hopkins was finding it challenging to remove iron spots from the raw clay materials used in making his own porcelain. Hopkins explains that purity is vital to achieve the white, glass-like finish of properly-made porcelain. He ultimately found a solution by installing an Eriez ProGrade rare earth grate magnet at the bottom of a home-made hopper where all raw materials pass before they are mixed together.

“The worst complaints I hear about porcelain is that it contains iron spots,” Hopkins says. “These are flaws that make a piece second quality, and I don’t sell seconds. Those pieces are given away or crushed into bits, wasting valuable studio time and money.”

Purifying Porcelain with a Grate Magnet
The raw clay material Hopkins purchases includes four basic ingredients: silica, feldspar, kaolin, and plasticizer. Each dry material is portioned out and then dumped into a homemade hopper constructed from coated plywood and corrugated PVC material. The Eriez 6 x 6 in. grate magnet is mounted at the bottom of the hopper.

“All the dry material passes through the magnet and the amount of impurity it attracts is amazing,” Hopkins says. “I have found almost all the magnetic impurity comes from silica, but feldspar is also a culprit for metal contamination.”

The self-made artist and entrepreneur discovered Eriez while on the hunt for an efficient and affordable way to detect and eliminate metal particulates in the raw clay ingredients. “Someone told me about certain bar magnets that are used to extract very fine particulate from dry clay materials — particulate so fine that it passes through a 60-mesh screen,” Hopkins recalls. “I remembered that conversation and starting to look around for a supplier. I contacted Eriez and purchased the 6 x 6 in. ProGrade magnet. The magnet is a purity enhancer and confidence restorer. It has become an invaluable part of my studio process and production.”

Eliminating Iron Spots in Finished Products
Metal contamination that is not eliminated early in the process can show up as iron spots or specks during the firing stage, which is when an unfinished piece is placed in a kiln and heated up to 2300ºF.

“Some artists don’t mind iron spots in their finished product, but I don’t find anything attractive about having specks in my pieces,” Hopkins says. “The Eriez magnet has made my clay cleaner and whiter and allows me to be more confident that the pieces I create will not go to waste because of iron spots.”

Hopkins describes that he has tried many different methods to eliminate iron spots over the past 23 years. “I have found there is no other practical way to remove them except with a magnet,” he says. “Considering what the magnet costs, it’s well worth the price.”

Hopkins sells his ornate art pieces to museums, private collectors, and even the general public. “I base my reputation on the quality of my work and how refined the ceramic pieces eventually turn out,” he says. “When I show my pieces to people in the ceramics world, they are envious that I have access to this Eriez magnet.”  

Eriez’ ProGrade grate magnets are available in various sizes and strengths to satisfy practically any application need. These powerful magnets remove fine ferrous contamination and are made with the finest materials and construction techniques. Assemblies feature stainless steel construction with painstaking attention to welds and finish. ProGrade grate magnets are in stock at Eriez and ready for immediate shipment.

Eriez’ magnetic lift and separation, metal detection, fluid filtration, flotation, materials feeding, screening, conveying, and controlling equipment have application in the process, metalworking, packaging, plastics, rubber, recycling, food, mining, aggregate, and textile industries. Eriez manufactures and markets these products through 12 international facilities located on six continents. For more information, call 814-835-6000, email [email protected], or visit www.eriez.com.

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