A heavy-duty hot knife is a very versatile tool, and can even be used in conservation efforts. Take, for example, the New York Public Library’s (NYPL) conservation lab, which includes creating custom-made containers or housings for some of their more unusual and fragile collections. In September 2013, the NYPL’s Manuscripts and Archives Division acquired a collection from the notorious psychologist Timothy Leary, who in the 1960s encouraged people to “turn on, tune in, drop out” and generally question authority.
This collection included a plaster mask molded from Timothy Leary’s face. Conservators made a special housing for the mask to protect it with a hot knife, contouring it to fit exactly around the mask’s perimeter. They used the hot knife to shape the polyethylene foam so that it would fit into the recessed area behind the mask, combining it with a soft foam layer to cushion and protect it.
What is a Hot Knife?
A hot knife is essentially just a type of soldering iron equipped with a double-edged blade. Powered by electricity, the blade is situated on a heating element that allows it to cut through materials more easily and make edges of the cut material seamless.
Sometimes referred to as an industrial hot knife, a heavy-duty hot knife can exceed temperatures of 900˚F (482 ˚C). Typically equipped with a power cord and operating at 115V, heavy-duty hot knives keep edges of cut material from splitting or fraying.
Hot Knife Accessories
Often a heavy-duty hot knife will have multiple tips, each used for a specific purpose. These generally will slide on and off easily when cooled, sometimes even including a soldering tip or woodburning tip to burn etchings into wood. Some industrial hot knives even include blank tips for making custom tips.
How to Use a Hot Knife
Before cutting, the material should first be prepared by laying it flat on a work surface with glass sheeting underneath to keep the surface safe from damage. This also prevents the workpiece from adhering permanently to the surface during cutting, which would ruin it. Depending on what is being cut, using a pattern or design tends to make a smoother edge, though material can be cut freehand. The working area should also be well-ventilated to keep from inhaling toxic gases coming off the melting material.
After plugging the heavy-duty hot knife in, the element should heat the blade in seconds. When working with hot knives, users should hold the tool as per a pencil or pen, though both the knives and workpieces should be treated carefully as both will be very hot. Once heated, the blade should slice through the material without stopping, as otherwise, it will cut unevenly. In nearly all situations, a heavy-duty hot knife will speed production by allowing cuts to material in advance, while keeping it from fraying.
Popular Applications
A popular tool used for crafts or hobbies, a heavy-duty hot knife can be used for creating advertising displays, building theater sets, working with model trains or for many other purposes. As with the NYPL’s conservation efforts, it can even help to make housings for protecting fragile historical artifacts.
Also used commonly in industrial settings, the heavy-duty hot knife is a key tool used by auto manufacturers. The heated blade cuts out plastic parts, door seals and flooring carpets. It also seals material when cutting, so is often used for creating seamless edges for ropes, gaskets, sails, carpets, webbing and other material.
Some of the many uses include:
- carving pumpkins for Halloween
- cutting plastics
- cutting through electrical sleeving
- etching
- making foam core board frames
- mounting rubber stamps
- resizing sail cloths
- sculpting
- slicing through synthetic marine canvas
- slicing through vinyl
- soldering
- woodburning
A heavy-duty hot knife can cut through and melt any synthetic material less than half an inch thick. With hundreds of uses, hot knives keep material from fraying while offering an even, yet appealing finish. If you’re in the market for hot tools M.M. Newman Corporation stocks a huge selection of quality hot tools and accessories.