Friday, February 16, 2018

Electric Heating 101: Ohms Law

The most basic circuit involves a single resistor and a source of electric potential or voltage. Electrons flow through the circuit producing a current of electricity. The resistance, voltage, and current are related to one another by Ohm's law, as shown in the figure. If we denote the resistance by R, the current by i, and the voltage by V, then Ohm's law states that:

V = i R

Resistance is a circuit property that offers opposition to the flow of electrons through a wire. It is analogous to friction in a mechanical system. The resistance is measured in ohms and depends on the geometry of the resistor and the material used in the resistor.

Other manipulations of Ohms Law:

Wednesday, January 31, 2018

Pre Weld and Post Weld Heat Treatment

Pre Weld and Post Weld Heat Treatment
Welding between insulated heating areas
Heating done by ceramic heaters (pink). 
There are several key reasons why it's important to preheat before welding. First, a preheated part cools more slowly, which slows the overall cooling rate of the welded part. This improves the metallurgical (crystalline) structure and makes it less prone to cracking. Additionally, hydrogen that may be present immediately after a weld is also released more efficiently, which further reduces the possibility cracking. Preheating also mitigates stress from the shrinkage at the weld joint and nearby metal. Finally, pre-heating reduces the possibility of fracture during fabrication due to brittleness.

An industry standard means of accurately managing the pre-heat and post-weld heat treatment is through the use of specialized electric heaters. Electric welding preheaters, known as "ceramic mat heaters", are rugged and flexible heating elements designed so that they conform uniformly around the weld and surrounding area.  Ceramic mat heaters are normally controlled by a power console that uses thermocouples and electronic controllers to regulate, monitor, and many times record, the preheat temperature profile.

ceramic mat heaters on spool piece
Ceramic heaters on spool piece.
Welding codes, gathered from years of rigorously tested data, including metallurgical science, chemical properties of materials, and radiographic analysis, provide specific detail on the minimum preheat temperature, the soak time, and the welding process to be used.

Before deciding to preheat or post heat any welding job, consult with a heat treating expert to make sure proper welding code requirements are being followed.

Saturday, December 30, 2017

Happy New Year from Hotfoil-EHS

With 2017 coming to a close, all of us at Hotfoil-EHS wanted to reach out and send our best wishes to our customers, our vendors, and our friends! We hope that 2018 holds success and good fortune for all of you.

Wednesday, December 27, 2017

Custom Fabrication and Manufacturing Services from Hotfoil-EHS

Security door
Custom security door.
Hotfoil-EHS has 68,000-square-feet of manufacturing space available for custom manufacturing. Capabilities include laser cutters, CNC machines, sheet metal breaks, Bridgeport milling machines, rollers and welding machines.

Hotfoil-EHS now provides full service custom metal fabrication including machining, metal forming, and welding, as well as a variety of other metal fabrication processes.

With years of expertise in forming, notching, punching, as well as MIG, TIG, and arc welding, Hotfoil-EHS’s experienced staff will work with you to make sure that your specifications are met.

From rapid design and prototyping to extended productions runs, Hofoil-EHS can provide all your metal forming and fabrication needs.
Examples of Hotfoil-EHS's custom manufacturing services are:
If you're interested in custom metalworking, or design and fabrication of any metal structural component, contact Hotfoil-EHS by calling 609.588.0900 of visiting

Sunday, December 3, 2017

AFTEK-EHS Shows Quad Arc Welder at International Workboat Show 2017

AFTEK-EHS booth at Workboat Show with Quad Arc Welder
AFTEK-EHS booth at Workboat Show with Quad Arc Welder.
AFTEK-EHS (a division of Hotfoil-EHS) just finished a very successful exhibit at the International Workboat Show (the show ran from Nov. 29 - Dec. 1). The International Workboat Show is a trade-only conference and expo for commercial vessel owners, operators and builders as well as the vendors and suppliers that serve them. AFTEK-EHS featured of their most unique and popular products, the Quad Arc Welder. 

The Quad Arc Welder is designed for heavy arc welding and engineered for low maintenance in harsh environments. It is simple to operate and reduces space by combining 4 welders in one package. It is protected with thermostatically controlled alarms on both its rectifiers & transformers.  Dimensions are 51" wide x 40" deep x 57" tall. The Quad Arc is a perfect choice for many of the attending vessel builders, owners, and operators.

For more information, contact Hotfoil-EHS by calling 609.588.0900 or by visiting

Wednesday, November 29, 2017

Custom Generator Trucks for Mobile Heat Treating

Hotfoil-EHS designs and manufactures custom Generator Trucks for remote heat treating applications. These truck-based, mobile heat treating systems are also know as Mobile Heat Treating Rigs.

Hotfoil-EHS will custom build a generator truck to your specification, with everything you need for a mobile, in-the-field heat treating system. Custom designs include a variety of generator sizes, power consoles, interior workspaces and layouts, air conditioning, and easy access to all electrical components. 

For more information, visit or call 609.588.0900.

Monday, November 6, 2017

The History of Hotfoil-EHS

Hotfoil-EHS Headquaters in Hamilton, NJ
Hotfoil-EHS Headquarters in Hamilton, NJ
Hotfoil has a long, established history of product innovation and quality.

Since its founding in the United Kingdom in the mid 1960’s, the company has gone through several changes in ownership and management. In 1993, my father, Neville Richards, and I took ownership of Hotfoil, Inc.

AFTek in Chatanooga, TN
AFTek in Chatanooga, TN
  • In 1996, Electric Heating Systems (EHS) was formed to provide equipment to the heat treating industry.
  • In 2007, we recognized the value of producing our own transformers, both for internal needs as well as external sales. Soon after, a welding equipment and transformer manufacturer named AFTek was acquired. AFTek-EHS operates today in Chattanooga, TN.
  • In 2010, was launched as the e-commerce division of Hotfoil and EHS, selling our line of heaters, controls, and heat treating consumables.
  • In 2012, Hotfoil and EHS merged into a new entity appropriately named Hotfoil-EHS, Inc. The merger produced an organization with over 70 employees and an impressive engineering capability.
Hotfoil-EHS in LaPorte, TX
Hotfoil-EHS in LaPorte, TX
Through continued re-investment of profits, Hotfoil-EHS subsequently acquired additional large fabrication facilities and assets, resulting in expansive facilities that include laser cutters, CNC machines, sheet metal breaks, Bridgeport milling machines, rollers and welding machines.

Today, Hotfoil-EHS is a full-service engineering, design, and manufacturing company for any type of industrial heating requirement.

Hotfoil-EHS in LaPorte, TX
Hotfoil-EHS in LaPorte, TX
From what started in 1993 as a humble 800-square-feet facility in a commercial office building, has grown to a total of 68,000-square-feet of manufacturing space located in Hamilton, NJ, Chatanooga, TN, and LaPorte, TX. In 2018, Hotfoil-EHS will open it’s first international location with the launch of a new Birmingham, England facility.