Hot wire cutting foam

[alan0043]

Hi Guys,

I came across this and wanted to share. Some old school Flite Test.

https://www.flitetest.com/articles/hot-wire-cutting-foam

 

[foamboardflyer]

Hi Guys,

I came across this and wanted to share. Some old school Flite Test.

https://www.flitetest.com/articles/hot-wire-cutting-foam

I’m not at home so I cannot take a picture of my hot wire cutter. But I made my cutter the exact same way.

 

[alan0043]

I’m not at home so I cannot take a picture of my hot wire cutter. But I made my cutter the exact same way.

Hey foamboardflyer,

When you get time, curious minds would like to see a picture of your hot wire cutter.

 

[foamboardflyer]

Hey foamboardflyer,

When you get time, curious minds would like to see a picture of your hot wire cutter.

Sorry it took so long to post this. I wonted to find out what gauge wire I used but I couldn’t find it so if you have any questions just let me know.

 

[Merv]

.....When you get time, curious minds would like to see a picture of your hot wire cutter.

Hot wire cutters are very simple, cheap and easy to make. Use whatever materials you have on hand, scrap wood, leftover PVC pipe, etc. Here are a few of mine, I have various size for the task needed. Lightweight frames are the best, very little strength is needed. The smaller frame is the one I use most often, it’s just stiff wire stuck into an scrap board. I added an on off switch for convince.

You can experiment with steel wire from the hardware store. There is no substitute for nichrome wire, it’s hands down the best. The site below has a great selection of wire and transformers, both in various sizes. Also has the calculators to help you pick the size for your needs. I use 26 gauge for cutting straight things like wings. Use 16 gauge for molding shapes, like crown molding or servo pockets. Bend the wire into whatever profile you want and cut away.

I use 12v & 5v transformers with a simple light dimmer switch to control the heat. I also use the same dimmer on my cheap hot glue gun. Full power at first to get it hot, then dial it back to about 60% to keep the glue from boiling.

https://jacobs-online.biz/index.htm

 

[foamboardflyer]

Here is the wire I used. I would recommend using a thicker gauge wire
https://www.amazon.com/dp/B07K9T85KS/?tag=lstir-20

 

[FlamingRCAirplanes]

I am interested in making a hotwire. I have some red 24 gauge magnet wire. Would that be thick enough? And how much current does one running of of 5 volts use? And how about 12? There obviously would be a lot of variation but a rough guess?

 

[foamboardflyer]

I am interested in making a hotwire. I have some red 24 gauge magnet wire. Would that be thick enough? And how much current does one running of of 5 volts use? And how about 12? There obviously would be a lot of variation but a rough guess?

Magnet wire wouldn’t work. You have to use a resistive wire like nichrome. The reason why you have to use nichrome is instead of conducting the electricity, nichrome resists it and heats up (like a toaster) Magnet wire would just make a short. I would recommend building yours using a old brush ESC and servo tester to get the best control. Because if you just put a battery on it you have no control over your bow.https://www.amainhobbies.com/great-planes-c12-micro-brushed-esc-w-bec-gpmm2015/p-quawtzeqtmzxactz This is the esc I used but you can’t get it anymore. you can use any servo tester

 

[FlamingRCAirplanes]

Magnet wire wouldn’t work. You have to use a resistive wire like nichrome. The reason why you have to use nichrome is instead of conducting the electricity, nichrome resists it and heats up (like a toaster) Magnet wire would just make a short. I would recommend building yours using a old brush ESC and servo tester to get the best control. Because if you just put a battery on it you have no control over your bow.https://www.amainhobbies.com/great-planes-c12-micro-brushed-esc-w-bec-gpmm2015/p-quawtzeqtmzxactz This is the esc I used but you can’t get it anymore. you can use any servo tester

Alright! Will try to get some nichrome wire. I have 5 brushed ESCs already from my RC car projects. Will use one of those connected to an Arduino.

 

[foamboardflyer]

You don’t even need a arduino (if you did I wouldn’t have made it ) this is a good diagram I found

 

[FlamingRCAirplanes]

You don’t even need a arduino (if you did I wouldn’t have made it ) this is a good diagram I found View attachment 211144

I know! But if I can make it use one I will! Just another hobby of mine!

 

[foamboardflyer]

I know! But if I can make it use one I will! Just another hobby of mine!

 

[foamboardflyer]

I know! But if I can make it use one I will! Just another hobby of mine!

I have seen people use Arduinos on their hot wire cutters (I’m guessing that’s were you got the idea) but I’ve wonted to make a FB needle cutter preferably @Edwardchew’s “timsav” which it uses a arduino uno with a cnc shield.

 

[FlamingRCAirplanes]

I have seen people use Arduinos on their hot wire cutters

Interesting! I never saw that!

but I’ve wonted to make a FB needle cutter preferably @Edwardchew’s “timsav” which it uses a arduino uno with a cnc shield.

That is also something I am thinking about. Seems like it wouldn't be too hard.

 

[foamboardflyer]

Interesting! I never saw that!

That is also something I am thinking about. Seems like it wouldn't be too hard.

This is the one I want to build.https://forum.flitetest.com/index.php?threads/erc-timsav-cheap-diy-cnc-foamboard-cutter.61018/

 

[FlamingRCAirplanes]

Finish my HotWire! I accidentally burnt out a 10$ Brushed ESC. Not a big deal. Here are some pictures.

That is the full bow. I made it out of some random PVC pipe pieces I found.

That is the battery and the battery alarm zip-tied to the bow.

That is the potentiometer and other electronics.

And here is the ATTiny13a that I used to turn the signals from the pot and turn it into PWM for the ESC. Works a treat. Glad I went with the arduino over the servo tester because it makes it all work in one tube. No need for other stuff. It runs off of a 2s 850mAh battery that was rescued from a sliced open cell. Changing it from a 3s to 2s lipo.
It uses about 775mA to melt foam so it should last somewhere near 30 minutes if left on the whole time. I am going to replace the battery with a 1.5Ah 2s battery. Should give me 1 hour.

 

[Merv]

.....And how much current does one running of of 5 volts use? And how about 12? .....

It all depends on how long of a run you need and the cutting temp of your foam. There is a huge difference from a 12" run to cut parts & a 36" run to cut a wing.

The table at the bottom of this web page will get you in the ball park for nichrome wire. Your wire will differ.
Nichrome 60 Wire (jacobs-online.biz)

This page has the rest of the information you will need.
Nichrome wire and transformer selection (jacobs-online.biz)

You can get 100 feet of nichrome wire for $10-$15, free shipping. Why use anything else?

 

[FlamingRCAirplanes]

I got 33 feet for $6. Good deal. It works great. Makes me think of maybe making a hotwire CNC machine.