Common (& not so common)
Questions and Answers

Foam Cutting How To's

Q How do I make circles in 20mm thick foam?

A Hey your English is way better than my French. To make a circle they put a series of grooves with the Engraving Tool on the inside of a thin piece of foam and curled the foam in toward the grooves. You can see the grooves in one of the pictures. The other way to make a circle is to put a nail in the center of a piece of foam, tie a string from the nail to the Hot Knife tool, pull the Knife taught on the string and spin it around the nail cutting a circle. If you are using foam over an inch thick (2.5cm) you will need the Sled Guide to make an even cut.

I don't know where to get such thin foam, so I make it myself. I clamp the bow cutter to a workbench with the wire facing up and slide the foam across the table and into the wire. You can make ultra thin sheets of foam using this technique. If you only need foam slices that are 8-12" (20-30cm) tall (they can be as long as you want) you can use the Scroll Table or 3D Table with the Fence Guide.

Q Date: Tue, 16 Jan 2001 13:09:19 -0500 From: "James Luciana" Hello, I would be using the Hot Knife and Sculpting Tool for carving various moldings, trims, and large architectural pieces for theatre sets. It seems that most users are working with small pieces, model RR's, etc. Would your products work for large pieces and props for theatrical use? Would the cordless kit with the knife and sculpting tool be a good choice? I doesn't seem that the engraver would be something I would need. I would be using the products for fairly long periods of time. Should I go with the AC adapter as well?

A Peter, We have sold tool sets to many theater groups, movie producers, and parade float creators with positive feedback from all. The Hot Knife and the Sculpting Tool would definitely be the good choices for detail work. Lego Land in Southern California recently bought one or our Pro Kits to make foam backdrops for their amusement park. We have also sold Pro Kits to Disneyland, Disney World, Knotts Berry Farm, Columbia Studios, the FBI, and the list goes on. The Nightmare Before Christmas scenes for the Haunted Mansion, the remodel of the Pirates of the Caribean, and Captain Nemo backdrops were made with our tools.

The Pro Power is used by most people who are doing serious projects. It has more power and outlasts the AC's. The tool extensions use a mini jack, so you can pick up a longer extension at any audio supply store or Radio Shack. You will need an extension with a male mini jack on one end and a female mini jack on the other.

Also, we have a new Freehand Router tool that has a stiffer cutting blade for more serious carving. The brass arms are shorter, and the cutting wire is 10" long. You shape the blades any way you want with your fingers or pliers and they will not bend while you are cutting. People who have tested the prototypes say that cutting foam with this blade is the fastest sculpting they have ever experienced in any medium.

We are also now making a Pro Hot Knife that is much sturdier and cuts faster than the regular Hot Knife.

We now have 2-4 foot bow cutters for knocking those big blocks of foam down to size! We are introducing an industrial hot knife, the Foaminator, which will literally smoke through the foam.

Q ROTTSHEPWOLF8@aol.com wrote: Do you have a hot knife to carve the pattern of a gun into the foam that comes in a gun case? Something like an ice cream scoop to take out some foam to lay the gun in. Thanks, Russ

A Yes, the Freehand Router is used for making cutouts in foam for packaging purposes. The other popular method is to buy one-half to three inch thick slices of foam and progressively terrace the pieces using the Hot Knife Tool. This is how the inside of many camera cases are designed. You can glue the pieces together after they are all cut out. Check with the foam manufacturer to make sure that there are no health or safety hazards when cutting their foam with hot wire tools. Here is a great how-to for cutting foam for cases: http://hotwirefoamfactory.com/customer/gallery/2_packaging.htm

Q Peter Thannhauser wrote: Dear Sir or Madam: My company manufactures large scale, composite model aircraft kits. The wings & flying components are made of 1 pcf poylstyrene foam using a hot wire mechanism for the airfoil surfaces. What is taking a lot of labour intensive time is what we call 'honeycombing' ie. removing cells of foam from the wing cores. Hopefully the attached diagram will give you an idea. I am interested in your hot knife tool to assist with this job. I'm thinking if I can secure it to a base to keep it perpendicular & plunge into the foam & around the cell perimeter guided by a single template, similar in action to a router. Presently I am using 2 templates on either side of the wing & feeding a thin wire through a pilot hole etc.

A Our Hot Knife is designed for plunge cutting. Look for the Sled Guide in our Accessories area to keep the Hot Knife perpendicular to the foam while cutting.

Q From: eric sandie [mailto:eyelusions@mindsync.com] Sent: Sunday, June 30, 2002 11:13 PM Hi I would like to know what you suggest that would be the best product for cutting logos/signs out. What would you use the Hot knife or the Hot scroll Table. The foam I use is 2 inchs thick. Thanks Eric Sandie

A Eric, It really depends on your skill as a freehand artist. Some people have the rare talant of being able to pick up a tool and make perfect freehand cuts. By far the majority of people making signs use the Hot Scroll Table or the 3D Table. It is much easier to keep the cutting wire perpendicular to the foam using the Table model. Most people, including myself, are not able to make nice looking letters with the Hot Knife. Did you find our helpful tips on making foam signs in the Gallery/Signs area of our website?

Q Do you have any patterns like scrolls and/or fancy moldings? They would be used for theatrical sets--carved wood is very expensive. If not, can you recommend anyone who would sell such patterns? colleen ryan

A Colleen, Here are a couple of URLs that have samples of moldings. It's very easy to duplicate the molding designs using the Router wire on the 3D Table. You can make fairly large moldings and can run them as long as you want. You can get super fancy by cutting out an outline of an object like a leaf or fish or whatever in a thick piece of foam, then slicing it into dozens of thin objects that you can then glue onto the molding. And, if you need to make them more rugged we sell large 50lb boxes of foam coat to theaters.

Q Subject: precise foam cutter Message: Hello, I need to cut out of thin foam various shapes-like dog's paws, tails, heads, ears and so on. My problem is that I can't find anything to cut those forms very precisely and in large quantities(scisors are not perfect cutting tool,and another manufacturer's hot knife that I tried burns the edges of the foam). I have a big request for You to advise me what would work. Please let me know, it is very important for me. Best Regards, Aga Lewis.

A Aga, I think that the Original Scroll Table would provide you with the most economic and accurate cut. This tool is also available with a Pro Power Station and a Fence Kit to provide even more accuracy and speed. Look in the Pro Kits area of our website. The 3D Kit is even more accurate and has more cutting features than any other hot wire tool in the world, but is the most expensive tool we offer.

Foam Cutting Tool Questions

Q How can I make 6 foot wings for my RC airplane with your tools?

A From your plans, cut out cardboard templates of the cross sections of your wing or fuselage every 6'', or closer where there is a drastic change in shape. Sandwich a 6", or appropriate length block of foam between these cardboard templates. It helps to pin the cardboard to the foam. Then just drag the hotwire around the templates, cutting out each section. You can even cut out the groove for the spar if you notch your cardboard templates in the right place. Glue the pieces together, and sand out any imperfections. Cover the finished wing or fuselage with fiberglass strapping tape and they will outlast the best balsa wood. (Save the rain forests!!!) Save your templates, they take longer to cut out than the foam.

Q From: EDWIN L STEVENS [mailto:edlstevens@juno.com] Sent: Tuesday, January 01, 2002 7:38 AM To: faqs@hotwirefoamfactory.com Subject: table cutter knife I PURCHASED A WOODLAND SCENICS FOAM CUTTER AND DISCOVERED YOUR WEB SIGHT. ARE YOU THE MANUFACTURER FOR THIER PRODUCTS? IF SO IF I ORDERED A TABLE AND/OR KNIFE FROM UOU WILL IT WORK WITH MY TOOLS ? THE HOT WIRE FOAM CUTTER IS ST1435. THANK YOU. EDLSTEVENS@JUNO.COM

A Ed, No. They actually purchased a set of our tools and made an imitation. We offered to manufacture them for them, but they said no, and they are having them made and packaged in China. Our tools require more power due to our longer cutting, so they are not compatible with their power supply. Our Hot Knife, Hot Scroll Table, and Sculpting Tool all work with either the Pro Power Station or the Crafter's AC adapter.

Q From: La Monk [mailto:aerostar@prodigy.net] Sent: Monday, May 27, 2002 6:29 PM Will your product cut through foam core board also? Does it burn the paper surrounding the foam or is it compatible to a clean cut? I would like to mount photographs onto a foamboard and cut around the picture to stand in a wood block. Will your product help me to do this? Thanks for any help...Linda

A Linda, No, a hot wire tool will not cut through paper. I have cut out pictures and glued them onto thin (and thick) pieces of foam and cut the foam off around the edge using the picture as a guide. I usually use DOW Blueboard or Pinkboard and paint it. Another cool mounting technique is to mount your photo to glass using Swiss Clips and then making a frame of any shape or thickness desired and rubber cementing it onto the glass. I made a very convincing granite frame for some waterfall photographs.

Q From: eric sandie [mailto:eyelusions@mindsync.com] Sent: Saturday, July 13, 2002 2:44 PM I know I have a lot of questions. Now it's coming down to the final question of purchase. What saw would you say I should go with if I'm going to be doing signs/logos etc. The Hot Scroll Table or the 3D scroll table? Thanks for all the help. Eric Sandie

A Eric, The Original Hot Scroll Table is much easier to set up and is less expensive. You can even use it with the AC Power Supply. People have been using the Original to make beautiful signs for over ten years. The 3D Scroll Table does some things that the Original does not, but you might not ever need these features for sign making. The added features are more for making models and architectural shapes. The 3D does have the benefit of letting you mount the Hot Knife using the Sled Guide as a rigid plunge cuttet, so you don't have to restring the blade for cutting the insides of letters like O's and D's. You will need the 3D if you want to contour the edges of the letters, or make shaped mouldings to frame the edge of the sign.

Q Subject: cleaning the equipment Message: The tips of my tools are getting dirty. I usually use them on blue foam core, and the material sticks a bit, so the tips have little bit of the melted foam stuck on it and i donno what to wipe it with.. or should i clean it with alcohol or something. I did not use anything on it, and wanted to ask u for the proper way before doing anything. hoping to hear from u soon, Nadia.

A Nadia, Most people clean their tools as they are working by just gently wiping them against a cloth or paper towell while the foam is in a melted state. If you feel the need to clean them even further you can clean them while they are cold with acetone. That Blueboard foam does leave a lot of residue.

Q Subject: replacement hot wires Message: I have an old Pro set (with an all black handle) that I bought 8 years ago. I finally broke my first wire but I can't find the replacement wires. I tried using 20 guage galvanized wire and 22 guage copper but neither work. Where can I get replacement wire quick?!?!? I am working on a model railroad module for a train show coming up next weekend. PLMK! Bill

A You probably need .010 or .020 Nichrome wire. Is the power supply grey or black? Using any other kind of wire will very likely kill your power supply. We can send you wires if you can't find them near you. Or you can call us at 866-735-9255 and we will try to find a dealer near you.

Protecting & Beautifying Foam

Q How do I protect foam when it is outdoors?

A Howard, I have not yet come accross a website dedicated to surfacing polystyrene foams, but I can give you a few tips.

The cheapest and easiest coating is outdoor latex house paint. If the foam will be in an area where people and animals won't be banging into it it will outlast painted wood because shrinkage, expansion, or rot will not occur with polystyrene foam, as it does with wood. My daughter made a sign for the local Mexican fast food restaurant nearly 10 years ago and it has held up to the elements better than most other signs that were made that long ago. It has faced right into a big rainstorm that was driven by 80+ mph winds. Pigeons apparantly have begun to peck into the edges of the foam.

We sell a foam coat that dries to a soft rock hardness. It can be sanded. If you make a 1/2" thick coating it will be very difficult to break or crack. This coating is slightly porous so you might want to seal it with paint. You can also stucco over the foam coat which has been formulated to adhere well to foam.

If you are looking for super stregnth you can fiberglass and epoxy the foam. Many kayaks and windsurfers are made this way. Never use resin directly on the foam as it will desolve polystryrene. You can use a coating of white glue as an insulating barrier from the resin.

We now have a complete Foam Coating system that will allow you to start with our ultrasmooth rock hard Foam Coat and add Boost to make it even stronger and weatherproof, or add Bounce to make a flexible waterproof coating. Try texturing with medium or coarse Grit. Apply a layer of Mesh for extreme durability.

Q From: Keifer0999@aol.com [mailto:Keifer0999@aol.com] Sent: Sunday, August 18, 2002 8:53 PM Subject: Paints on foam. Just wondering....what types of paints do you recommend using? interior or exterior? acrylic latex? etc etc. Thanks Keith

A Keith, Always use water based paints. Acrylic latex is fine. If your project is going outside use exterior paint as it will not fade as fast as interior and will protect the foam longer. Always test the paint on a scrap piece of foam since there might be additives that dissolve foam. It can take a couple of minutes for the foam to dissolve. Unfortunately, some paints have mild solvents that will slowly eat at foam for years but will seem fine at first.

Q Many customers have asked: How can I slow down the set time for Foam Coat so it doesn't harden before I finish applying it?

A We recommend adding latex paint instead of water. It doesn't seem to weaken the Foam Coat and can give you up to well over 40 minutes working time if you mix it straight with no water. I don't think that this has any affect on the longevity of the Foam Coat. I wouldn't suggest any of these techniques in combination with the liquid fortifiers.
One of our customers said suggested adding a couple of packets of sugar to the Foam Coat: If sugar is present in concrete ,it delays setting time of concrete.so sugar act as a retarder. If sugar presents 0.5% to the weight of cement ,it delays setting time 2-3 hours. and if sugar presents more than 2% to the weight of cement, then concrete setting delay several days or more.

Q Kim Fry asked: Have you heard of anyone creating their own faux stone veneer for the outside of their home, and if so, with what degree of success? We would be wanting to glue it to concrete and wood. I'm an artist, so I think I could create a realistic look with the right materials. However, it's probably cheaper if I just buy it already fabricated. I actually want the hot wire kit more for sculpture than home improvement, but I figured I'd check out my options.

A Kim, We don't have any examples of faux stone veneer in our Gallery yet, but you can get some pretty good ideas by looking at the tombstones people have made. Also look at the rocks that Boulder Image has built for their waterfalls, also on our website. I talked to an artist that was restoring the outside of a brick building who said he and his customer were very happy with the red brick veneer that he created. I see no reason that you can't create any exterior finish you want with a foam substrate. Did you see the realistic 'woodwork' that a theater group created for "My Fair Lady" (not to mention the stone walls and plaster crown molding)?

Types of 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 From: Ilan Brami [mailto:bramilan@yahoo.com] Sent: Tuesday, August 20, 2002 10:11 AM Hi. I am looking for a possibility of cutting foam in different forms for sciences experiences. I could not understand from your site if ANY kind of foam can be cutted with your tools or only some kinds. I would also like to know if there is a place in Israel where we can buy your stuff. If you can also send me some technical details about your tools and their abilities, it would be very helpfull. Thank you very much in advance. Ilan Brami.

A Ilan, Our tools are designed for cutting rigid polystyrene foams, also known as EPS (expanded polystyrene) and XEPS(extruded polystyrene) foams. EPS foam is made up of little beads which vary in sized according to the density/weight/strength of the foam. XEPS 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. EPS is often used to insulate electrical appliances when they are shipped- your computer probably came packaged in EPS foam. Be very cautious before cutting any foam. Many foams are flamable and give off toxic fumes. ALWAYS check with the manufacturer of the foam for any health or safety hazards which could occur when cutting foam with hot electrical tools. I hope this helps. Please don't hesitate to ask any specific questions. We do not have a dealer in Israel. We will help you with shipping costs if you would like to order directly from us.

Q Hi 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 Jan, 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 lthe pool for aerobics. Thanks for making me smile. So, if you do know, I would appreciate a real answer. Thanks, Jan

A Jan, I honestly have never heard of foam noodles, so I have 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. So, you will have to contact the manufacturer on this one. Sorry I couldn't help, but glad I made you smile!
I recently discovered that foam noodles are made from polyethylene foam, which can be cut with hot wire tools.

Q From: mikelli [mailto:mikelli@fayette.net] Sent: Sunday, October 20, 2002 10:26 PM I would like to know if your products have a thermostat control on them. I make beeswax candles and I am looking for some "tools" to design and cut the wax. Thank you, Kelli Burnett

A Kelli, Hey, I just tried our new Pro Hot Knife on a regular candle, and it cuts fairly fast if you saw back and forth as you cut (though not quite as fast as the Candlecutter), and if you tilt the candle as you cut the wax drips out instead of resealing the cut. The Pro Hot Knife has a round blade so you can easily change the direction of your cut and also make holes. It looks just like the Hot Knife on our site, but it's longer and a little thicker. It will only work with the Pro Power Station. Let me know if you have any specific tests you would like us to run.

Q Will you ship to a school on a purchase order and if so what more would you require?...I am interested in buying one of your comprehensive kits with multi pools and shapable wires and foam lathe kit.

A Yes, we do accept school purchase orders. Just fax or email it to us and we will ship your order via UPS. Our fax number is 805-735-9285.