Common (and not so common) Questions & Answers
Frequently Asked Questions about Foam
Always check with the manufacturer of the foam to make sure there are no health or safety factors when cutting their foam with hot wire tools.
Q: What kinds of foam can I cut with Hot Wire tools?
A: Hot Wire tools work best on rigid polystyrene foams, also known as expanded polystyrene (also known as EPS or bead-board foam) and extruded polystyrene foam (also known as XEPS or XPS or insulation foam). EPS foam is made up of little beads which vary in size according to the density, weight and strength of the foam. EPS is often used to insulate electrical appliances when they are shipped. XPS or XEPS foam is smooth and also comes in various strengths. These foams are often found in building supply stores and packaging supply outlets as they are used for insulating walls in homes and for padding in packages. DOW Blueboard and Pinkboard are XEPS foams that are used for insulating.
The tools will also cut expanded polypropylene (EPP) and flexible foam like polyethylene (PE) foam. The Hot Wire tools will cut many kinds of foam, but always check with the foam manufacturer to make sure there are no health or safety hazards when using hot wire tools.
Q: Are the fumes that are given off when cutting polystyrene foams (EPS or XPS foams) with hot wire tools dangerous?
A: Ventilation is always strongly suggested, but the smoke that you may encounter while cutting EPS foam is primarily CO2 and water vapor, which are far less harmful than other common art products like aerosols and paint thinners. The toxic values are far less than wood-smoke, which contains tars, resins, creosote, and acetic acid. The dust from cutting with saws and sanding EPS foam is more harmful than the fumes encountered while cutting foam with a hot wire tool. Always wear a good quality dust mask when saw cutting or sanding polystyrene foams.
To get the polystyrene foams to actually combust and burn you have to have an extremely hot fire, much hotter than our tools get, burning directly on the foam to begin with. Always check with the manufacturer of the foam you are using to make sure that there are no health or safety hazards when cutting their foam with hot wire tools. Keep in mind when you read the Material Safety Data Sheets (MSDS) for the foam you look up that they often are referring to possible safety hazards when manufacturing foam, not cutting it.
You can call our toll free number at 1-866-735-9255 and we can give you the tech-support number for DOW which manufactures Styrofoam. They told us that the fumes from cutting their foam with a hot wire are not toxic, but cutting should still be done in a well-ventilated area. (On the other hand we have had many personal testimonials claiming that they have become addicted to foam cutting. Could it be the fumes or is foam sculpting is way too much fun?)
Q: I was told foam might present a fire hazard, is this true?
A: For those using foam for stage props and backdrops instead of plywood, fire marshalls may ask questions about the fire safety of foam. EPS foam is now commonly used all over the world in huge theaters and auditoriums with thousands of people. Once the fire department looks at the fire spread and toxicity of foam compared to wood and cloth, they are ecstatic. You can hold a torch to EPS foam and it will stop melting/burning the second the flame is gone. The ‘smoke’ is mostly hydrocarbons and water vapor. This page from the EPS Industry Alliance has information on fire performance and safety. There is also this helpful PDF from EUMEPS which goes over the behavior of EPS in case of fire.
You can also call or look on the DOW Chemical site, as they hold the patent on its manufacturing process. They have all the Material Safety Data Sheets (MSDS).
For architectural or large projects where fire could be a potential danger, we recommend all foam is coated to prevent spread of fire. Below is the section from the Foam Coat MSDS showing the fire data:
FIRE AND EXPLOSION HAZARD DATA
Flash Point (Method Used): Non-combustible.
Extinguishing Media: Use extinguishing media appropriate for surrounding fire.
Special Fire Fighting Procedures: None
Unusual Fire and Explosion Hazards: None
Special Fire Fighting Protective Equipment: None
Q: Is using foam “Earth Friendly”?
A: Expanded polystyrene (EPS) foam is recyclable and is a pre-existing waste byproduct of petroleum refinement. It takes less energy to make than paper and causes less pollution in the process. A great way to acquire foam and be “green” in the process is to check with local appliance and computer stores, which may normally throw away the EPS foam they accumulate from packaging.
Q: What kind of foam would you recommend for building layouts with Dept 56 buildings or for trains? Do the pink and blue foams cut as well as the white? Which is better for making a rigid structure?
A: Most people use the white beaded foam (called EPS for expanded polystyrene) as it is the least expensive and easiest to find and cut. It is great for making terrain like hills and mountains. If you need it to be tougher, or want to hide the little beads, you can coat it with our Foam Coat. Adding a little bit of our Grit Texturizer to the Foam Coat will give the coating a natural rock-like texture for very realistic looking mountains.
The Pink or Blue foams (sometimes called X-EPS or XPS for extruded polystyrene) are usually used for making detailed structures like walls and buildings. Although they do not cut as fast as the less-dense EPS foam, they cut very well with our hot wire tools. If you want to make a diorama that is very light for storage or portability you can use 2″ or thicker Blue or Pink foam for the structural base of the diorama rather than wood or a table. One of the other advantages of using foam as a base is that you can use the hot wire tools to make holes to bring all of your unsightly wiring straight down all the way to where your electrical hookups are, just like underground utilities.
Q: Can your tools be used to cut polyurethane foam? (sold as camera and gun case foam)
A: We have been getting a ton of requests for a ‘museum quality’ foam for camera cases and gun cases that can be cut with hot wire tools, so we now have a solution. Not only is polyurethane foam difficult to work with as it cannot be easily cut with hot wire tools, but it also off-gasses and degrades and damages the instruments it is supposed to protect. We recommend that the polyurethane foams only be cut with a blade or saw.
We now offer Armorfoam, which is easy to handle, cut, shape and form, and is widely used in protective packing of fine art, artifacts and sensitive instruments, for both transportation and storage. It is a tough, flexible thermoplastic resin which, being inert and chemically stable, meets all preservation standards. Also, check out this post we have in our Gallery section about making foam inserts for instrument cases. We also offer sturdy plastic cases in our Accessories section. These are exactly the same as the pistol cases that are used for traveling and approved for airline transport.
Q: Can your tools be used to cut polyethylene foam? (sold as camera and gun case foam, “Plastazote” or “Ethafoam”)
A: Hot wire tools will cut polyethylene foam, but will give a slower cut as they are generally more dense than EPS foam. As these foams are denser, make sure that you don’t put too much pressure on the blade or wire of your tool, as this could cause it to bend and eventually break. The manufacturer of Zotefoams USA told us that their foams are safe when cut with a hot wire. Many of our customers use hot wire tools to cut Ethafoam and other polyethylene foams, but I always suggest that they check with the manufacturer of the foam to make sure it is safe to cut it with hot wire tools.
Our Armorfoam is a polyethylene foam and is easy to handle, cut, shape and form, and is widely used in protective packing of fine art, artifacts and sensitive instruments, for both transportation and storage. It is a tough, flexible thermoplastic resin which, being inert and chemically stable, meets all preservation standards.
Check out this post we have in our Gallery section about making foam inserts for instrument cases. We also offer sturdy plastic cases in our Accessories section. These are exactly the same as the pistol cases that are used for traveling and approved for airline transport.
Q: Can your tools be used to cut polyurethane foam? (sold as upholstery foam and “poly foam”)
A: Polyurethane foam should not be cut with hot wire tools. It needs a ton of heat, gives off toxic fumes, and leaves a lot of melted plastic wherever it is cut. We recommend that the polyurethane foams only be cut with a blade or saw.
Q: Can your tools can be used with PVC-based corrugated sheet like Coroplast?
A: I have done some cutting of Coroplast with my Hot Wire tools. It cuts a bit slow and leaves a ridge that can be broken off. A razor blade is faster for straight cuts, but the hot wire tools come in handy for curves. The Sculpting Tool with the wire just past 5″ long cuts the best. As always, you will need to check with the manufacturer to see if there are any health or safety hazards when cutting their material with hot wire tools.
Q: Will your 4″ hot knife cut 3mm thick craft foam? The brand I buy is Darice Foamies, and I use it to create my own stamps for mixed media art work by gluing pieces to acrylic squares and then inking the foam. Scissors and Exacto knives cannot really create clean cuts. If the 4″ knife won’t work (maybe it’s too long), what would you suggest?
A: I don’t think that this type of foam can be cut with hot wire tools. I looked it up online and although they don’t say what it is made from, I think it is a polyurethane foam which does not cut well with heat, and gives off toxic fumes when cut with a hot wire. If you can find a way to contact the manufacturer maybe they can tell you for sure. We have made some pretty cool stamps out of the DOW Blueboard and Pinkboard foams. They seem to ink up well without dripping. The 4″ Hot Knife cuts this foam well, but I usually use the Original Scroll Table for better control. With the Scroll Table you can cut a thick piece of foam into your stamp shape, and then slice it up to make extra stamps.
Q: Will your hot wire tools work on Michaels artificial foam pumpkins, or Funkins artificial pumpkins?
A: It is polyurethane foam, which should not be cut with hot wire tools. It needs a ton of heat, gives off toxic fumes, and leaves a lot of melted plastic wherever it is cut.
Q: I want to make a medium sized sculpture of an animal, but can’t find a big enough block of foam. Can you help?
A: Finding big blocks of foam is always difficult. They are ‘oversize’ for shipping via UPS, so it is not economical to ship them. Most people buy the EPS insulation foam at a building supply store in 2-4″ thick by 4’x8′ sheets and stack them, holding them together with skewers while cutting, and then gluing the pieces together after they are sculpted. The seams are easily hidden with a little Foam Coat. Check out this dog sculpture. You will see how Colleen glued pieces of pink insulation foam together. We do sell 12″ x 14″ x 22″ foam blocks on our website.
Q: I am having trouble finding the pink foam in my area. Maybe it’s not cold enough? I did find polyurethane foam sheets with a thin layer of foil on both sides. If I peel off the foil, will the hot tools work on that type of foam or do I need to look harder for the EPS?
A: The polyurethane foam is very toxic and won’t cut well with heat. You should be able to find the white beaded EPS insulation foam though. It often has a thin, clear plastic moisture barrier that peels right off. This is much easier to cut than blueboard and pinkboard. It has a memory, so if it gets squished a little it regains its shape. It is lighter and much less expensive. Usually people who are doing fine scale modeling use the extruded blueboard and pinkboard because it doesn’t have the bubbles. You can put a thin layer of Foam Coat on to cover up the bubble texture if that is an issue. You will find that the white beaded EPS foam when coated with Foam Coat is more economical, nicer looking, lighter, and easier to work with.
Q: What is “open cell foam”?
A: Open cell structured foams contain pores that are connected to each other and form an interconnected network which is relatively soft. The “crunchy” foam found in floral craft projects is an example of open cell foam.
Q: What is “closed cell foam”?
A: Closed cell foams do not have interconnected pores. Normally the closed cell foams have higher compressive strength due to their structures. The closed cell structure foams have higher dimensional stability, low moisture absorption coefficients and higher strength compared to open cell structured foams. Examples of closed cell foams include expanded polystyrene (EPS), which is made of pre-expanded polystyrene beads, which is why it is sometimes known as bead-board foam. It is generally seen as blue, pink, yellow and green insulation sheets. Extruded polystyrene foam (XPS) is also a closed cell foam, and trade names for XPS foam include “INSUboard,” “Styrofoam,” “Foamular,” “Greenguard” and “Foamcore.”
Q: We need to protect hand gauges while in storage. We will be placing polyethylene foam in Lista cabinet drawers and be cutting out “beds” for various measuring instruments such as: OD micrometers, thread gauges and other various pieces of equipment. We will not be cutting through the foam but be cutting shapes into the foam for the gauges to lay. What tools do you suggest we use?
A: Our tools will cut through polyethylene foam, but not nearly as fast as the white beaded EPS foam. The finer the blade, the faster and nicer the cut. It takes about three seconds to cut one inch and there is a buildup of melted foam that has to be wiped off of the 4″ Hot Knife and Freehand Router in between cuts. I am not sure what your cutting needs are, but rather than buy the K47 Kit, I suggest buying the K44P6 Kit, plus buy the Sculpting Tool separately. The Pro 6″ Knife cuts the foam much quicker than the 4″. I am also concerned that you might break the blade on the 4″ cutting through this tougher foam. Here is a link showing our tools being used to cut some polyethylene foam. We have tried cutting polyethylene foam with more heat, but the residue carbonizes onto the blade to the point where it stops cutting and is very difficult to clean off. You should check with the manufacturer for the Material Safety Data Sheets (MSDS) for their foam when cutting it with heat.
Q: Would you please let me know if fun noodles are made from latex foam? I have a latex allergy and need to know if they are made from latex. Please advise.
A: Although it is not my field of expertise I would imagine that most people would suffer some negative side effects from eating any kind of foam noodles. Hot wire tools will not work with noodles made from flour, but I am sure flour noodles are more healthy. You really need to ask the foam noodle manufacturer. Our tools are designed to cut polystyrene foam, like the foam we sell.
Q: You obviously have a great sense of humor, but I really need to know if the foam noodles are made out of latex, as I have a serious allergy to latex. If you can possibly assist me as to whether or not the foam noodles are made out of latex, it would be nice to know. By the way, I don’t have any interest in eating them, I just want to use them in the pool for aerobics. Thanks for making me smile.
A: I honestly had never heard of foam noodles, so I had no idea what they are made of. In fact, I thought you were putting us on. We do get many of those kinds of emails. When I looked into it, I found that the foam noodles are made from polyethylene foam, which can be cut with hot wire tools.