hot wire foam cutters

[Vtool]

Does anyone have any experience with using hot wire foam cutters? my wife's father designed a hot wire cutter for foam insulation. he made alot of money off his design. it made it possible to use thinner layers for industrial buildings. I figure use his experience and maybe design a portable unit for auto and boat foam repair and replacement. also this gives the two of us some common ground to relate to each other.                                                                 David

[kodydog]

Just thinking out loud here. Seems like the heat would melt the polyurethane foam causing it to form a "skin". I'm wondering what the appearance would be when stuffing a 4" foam into a 3-1/2" casing. Over time, would it cause the skin to wrinkle? Or would it give the border a stiff feel?

The next question is would it be faster or more economical than an electric foam cutter? A Bosch foam cutter is between $300 and $350. Can you build, market and sell for less than that.

Interesting concept. We love creative ideas in this forum.

All you can do is try and see. Let us know.

[scottymc]

A guy I worked for in the 80's made one, he used it for cutting poly styrene foam to shape surfboards. It was pretty crud, basically a wooden bow with a fine wire and positive and negative connected to each end and plugged straight into 240v, scary stuff. :o   

[Bob T]

I made my own hotwire foam cutter following instructions I found doing a Google search for "How to make Hotwire Foam".  It really was quite easy using a standard 110v transformer for 12v track lights and a dimmer.  These are readily available at most lighting stores. The tough part is getting the right wattage transformer.  If you go too small, the wire won't get hot enough and will cut very slowly.  I think I used a 250 watt transformer but should of used a 500 watt transformer. With the 250 watt transformer, it cuts slow because the wire doesn't get hot enough even on max heat.  I've never got it hot enough to cause the wire to become weak.  The Dimmer controls how much of that wattage goes thru the hot wire itself.  You can also use a model train transformer, but I have no knowledge of what size works.  I think I wound up spending about $60 for the hot wire, the PVC plastic pipe bow, the transformer, the dimmer, and the misc. electrical cords.  Took about 1.5 hours to make it.

I know you can find instructions on making the hot wire  here:
http://www.garageofevilnetwork.com/   but the website is a nightmare to navigate and find the instructions to build the power unit. You have to join first, then when you get into the site, click on "HOW TO" at the top and when it comes up scroll about half way down the page to "PETES How-To!,Hot-Wire Foam Cutter, Core, variable power, Power Supply, for $20"

I use mine to cut styrofoam to build my own windsurfers.  It works fine with styrofoam but does not work so well with urethane foam.  If you try to use it to cut urethane foam, do it outdoors because the fumes are said to be noxious.

[Vtool]

after reading the responses. I will get a bosch foam cutter.  thanks for the heads up on toxic fumes.
                                                       David

[Mojo]

David:

If you do a search of this site you will find a thread started by June on a vendor who had great prices on the Bosch foam saw.

Myself I cut such little foam that I use an electric turkey carving knife. It works good you just have to spray the blades with silicone spray now and then. I would love a Bosch saw but just cannot justify the expense when I cut very little foam every year.

Chris

[JuneC]

The Bosch works great!  I got a new one, but occasionally one comes up on EBay for a very good price.  I put in bids on several and always lost  :(

One thing surprised me though, it's a very heavy tool.  I get fatigued when doing a lot of foam cutting like I have been lately.  I suppose it's well built, though, lots of metal.  Another thing.  It has a lot of torque when starting.  Definitely start the blades before making contact with the foam.  And... I'd love it if the body was just a little smaller.  My hand can barely fit around it.  I can only press the trigger with the very tips of my 2 middle fingers.  This probably contributes to my fatigue.

June

[Judy_Boat]

Hi all,
I have built the hot wire cutter and tried the upholstery foam on it.
Do not bother for this use. Stick to styrofoam with them.
Basically, the foam cut so slowly, it dragged hard enough on the wire to force the wire to curve, causing a wobbly cut. It did not cause a skin to form.

On a different note with holding the Bosch cutter for a long time. I have clamped the stabilizing foot to my table  top and then just shoved the foam past the blade. I find it works nicer when shaving small sections off.

[fragged8]

I have a foam saw from this site, it works well and very good price

the blades were like $9 but the bosch ones in the Uk are about $150

support Ken (site owner) and check his shop out
no he isn't paying me heheh

http://www.get-up-and-go.com/mm5/merchant.mvc?Store_Code=G&Screen=PROD&Category_Code=TS&Product_Code=foam-saw

[Rich]

If you already have a band saw, you can cut foam with that too. Actually, I found that out here on this site and was amazed at how well it cuts. Increased the usefulness of that machine considerably for me!
Rich

[gene]

Hey Rich,

I have been looking at a band saw to cut foam. The cost of foam is getting higher and higher and I have been thinking of cutting and gluing scraps together more than I have in the past.

I used an electric turkey knife today to cut 5" foam into strips that are 2 1/2" thick so I could glue them up and have a 2 1/2" cushion insert. It worked well but the turkey knife was working rather hard.

Do you have a special set up for the band saw, such as a large table to feed the foam, or does it work well just as it is?

Thanks,

gene

[kodydog]

I worked for a guy in Gainesville Fl who made a foam slicer. He took a band saw and mounted it sideways on a frame.

Beneath it he built a platform out of plywood and mounted small wheels to it. This gave it forward and backward motion to feed the foam into the blade.

The platform was supported by small hydraulic jacks for up and down motion.

He could take up to a 36" wide piece of foam and slice it any thickness you want.

[Vtool]

we use a band saw at work to cut foam. after looking at price of complete bosch foam saw. thats insane. I could get a nice bandsaw for a cheaper price. only advantage of bosch foam saw. small size compared to bandsaw. also bandsaw is multi use over bosch. I discussed this same subject with fellow co-worker yesterday. thanks for input everyone. saved me from toxic fumes of hot wire.
                                                                                    David

[Peppy]

Wow June, you must have itty bitty hands! I had to go look at my saw to see if we were talking about the same bosch. Can't you lock the saw on? On mine when it's running you can slide the switch back and it will stay running.

In my mind the other advantage to a foam saw over a band saw is the foam saw ONLY cuts foam and so does it very well and with great agility. I can cut a wedgie 6" to 0" on a six foot piece with nothing more than a line on the foam. A band saw is very good to have, but it doesn't replace a foam saw of some kind.

[JuneC]

I don't think I could have done this with a band saw.  I'm doing lots of carving on this project.  Luckily, DriFast 70 carves really easily since it's so firm. 





My saw has the switch lock which helps, but it takes two hands to get it on, then off.  I'm just getting used to handling the thing. 

June