Introduction: DIY Variable Depth Hot Wire Foam Slot/ Hole Cutter

About: I'm a RC enthusiast. Looking to make composite glider, etc.

Hi all DIY enthusiast, this is my first Instructable.

I was into RC foamies in the recent months. I made DIY gravity feed cutter for cutting various wing profiles easily but I found its very difficult to use reinforcement. Generally I used plywood as stiffeners in my foam wings. I need to use my dremel tool to make the slot for fixing 4mm plywood. It was not smooth and finishing is not as expected.

So I made a variable depth hot wire foam cutting scoop tool for making slot/ hole or to cut foam boards at any angle.

Hope you all enjoy and use this DIY in your upcoming foam cutting techniques!

Step 1: Materials Required

Following materials and tools are required.

  1. 5mm ply wood strip
  2. Wire
  3. 22 SWG Nichrome wire
  4. 3.5 mm male and female connector
  5. Lug
  6. 4mm nut & bolt
  7. Shrink tube
  8. 5 min cure epoxy
  9. Quick fix
  10. Soldering kit
  11. Screw drivers
  12. Drilling machine
  13. 4mm Drill bit
  14. Dremel Tools set
  15. Scroll saw (else axe saw)
  16. Nose pliers
  17. Scale

Step 2: Preparing Wood Strips

Cut the wood strips for below dimension. (you can vary the dimension as per your need)

There are four strips

  1. Main support strip - 70mm
  2. Spacer strip - 45mm
  3. Sliding strip - 55mm
  4. Bottom support strip - 30mm

Use 4mm drill bit to drill as per the shown in the 2nd picture and make a slot in the sliding strip as shown 3rd picture.

Pitch to pitch distance for main & spacer strip is 25mm and 8mm for sliding strip

Use your dremel router bit to remove excess wood to fix the nut as shown in the 4th picture.

Step 3: Applying Epoxy to Wood Strips

Ensure all the nuts are placed at 2.5 mm depth and apply 5 min cure epoxy.


  1. Nut to be fixed inside between main support strip and sliding strip using 5min cure epoxy.
  2. Ensure there is no epoxy applied on to the sides only.

Step 4:

Solder the wire with lug and 3.5 mm male connector and fix it with shrink tube.

Fix the soldered wire to the sliding strip using quick fix.

Fix the bottom support strip to main strip using quick fix.

Step 5: Now Assemble It!

Now fix the nichrome wire profile into sliding stip, and fix the sliding strip on the main support strip.

Paste a graph sheet for easy measurement on the side.

Your HOT WIRE SCOOP TOOL is ready!!!!!!

Step 6: Nichrome Wire Profile

Use 22 SWG nichrome wire. Its more optimum to use this wire since its rigid and gives clean cut without much deviation. You can simple bent the wire using nose plier.


  1. Rectangular
  2. Circular
  3. Square
  4. Half circle
  5. and more

Step 7: Using Foam Scoop Cutter