About: Last time in my life that I saw the moon that close to me... I was born in the capital city of a country that no longer exists.... I'm in my own timeline and an Electronic Engineer... Received a BSEE degree f…

My grandson who likes to be called "Captain of Light " wanted to be a 60s blue Battling Robot for Halloween.

BTW he got Second Prize at the community event !!

So we set-off to gather materials.

And found a 4' x 8' by 2" thick, slightly scratched Styrofoam insulation sheet sold to us at a discount.

Absolutely NO Styrofoam Dust in this Project !!!

Some glue ( never found the best glue ) and gorilla did not work so well.

And a helmet to fit the Captain of Light's head, procured for free when he won in the Mutton Busting Contest at the Reno Rodeo.

Step 1: Gathering Materials

With the styrofoam sheet leaning against the wall, peeling the silvered Mylar off of one side was quick and easy for the Captain of Light... You end up with raw styrofoam on one side and the manufacturer label on the other side.

Score the foam with a sharp knife and break the sheet into two 8' x 2' sections.

  • Then score and break a total of six 18" x 2' layers
  • Glue three layers foam, raw foam side to label side
  • Place about ten pounds of weight on top and let it set over night
  • The Gorilla glue was my poor choice for the application because it does not easily cut by Hot Wire !
  • Next time I plan touse Elmers White Glue instead.
  • A 3/4" diameter three foot long wood dowel rod
  • Two 3/32" mild steel welding rods are used as the hot cut wire
  • Some blue paint.

I already had

  • A boy's Helmet
  • The 5 Amp variac
  • Hookup wire
  • The Stancore P-6379 twelve volt 16 Amp control transformer
  • Split bolt and wire twist connectors

Later you will also need ;

  1. A 12 volt 15 blue LED strip from eBay ( 4 strips for $6 )
  2. A 1N4001 Diode ( $0.34 )
  3. A slide switch ( $0.50 )
  4. A push button switch ( $0.50 )
  5. A small stiff card or fiberglass hook up board.
    • A 9 volt battery ........... ( had it )
    • A battery connect clip ( had it )
    • 30" of speaker wire cable ( had it )

Step 2: Ready a HOT Weld-Rod Styrofoam Cutting Electrical Circuit.


You do need a variac to easily adjust the power level thats sets the Current and result Heat level in the weld rod..... Mine was working with dial settings from 40 to 55....Your set up may use a higher if using a smaller transformer..

The transformer is a magnetic AC isolation component that lowers the voltage by ten and increases the heating current capability by 10 ... In actual use the transformer, the variac or wiring never even warmed up.

My transformer is wired 120 Volt Primary :to: 12 Volt Secondary capable of continuous 16 Amperes output.

Using a Fluke clamp on ampere meter measured 20 to 40 amperes for the short periods needed to heat differing lengths of weld-rod shapes and make the styrofoam cuts.

To connect the transformer secondary using the short extension cable electric wires to the 3/32" shape holding weld-rod.

You should use the wire slot or split bolt to make a good connection between weld-rod and braided copper wire [ see second to last picture ]. This will avoid heat where you don't want it ....


Now we are ready to cut a spot for the helmet.


  • Drill a 1/8" hole in the wood dowel and mark where other side of the helmet will clear then
  • Drill a second hole and don't worry if you need to correct the holes its only a tool.
  • Bend a weld-rod in the shape of your helmet and slide the ends into the dowel holes bending the remainder of the wires to outline the helmet narrow cross section [ see picture 2 ].
  • Make sure the loop is shorter then your three styrofoam previously glued layers.
  • Attach the cable wires to the weld-rod ends.
  • Do this close-in to the dowel using the two split bolt connectors [ see picture 5 ].


  • Draw a helmet outline in the center with a red marker [ picture 6 ].
  • Turn the variac dial to 30, plug the transformer into the variac [picture 7 ]
  1. Put on some gloves.
  2. Flip the variac switch ON !
  3. Take a waste styrofoam and see if the rod goes through it like butter.
  4. IF NOT add 5 to the variac and repeat # 3.
  5. Place the dowel across the styrofoam block of three layers at the center of your helmet mark [ picture 8 ].
  6. Now rotate the dowel to cut the foam half dome [ see pictures 9, 10 and 11 ].


There is a simple LED strip driver circuit you can build that I will cover later.

Fit That Helmet ;

Because the helmet is longer then it is wide. A slightly different narrower hot rod dowel tool is needed .

  • Re-bend the weld-rod to become a longer more narrow shape [ picture 3, 4 & 5 ].
  • Cut and fit the helmet into the three layer styrofoam block.

Cut a round head hole in each layer 4, 5 & 6 ;

Use the same narrow tool from fitting the helmet to cut each head hole.

Tip => pin the layers together ..

Then glue layer 5 to layer 6 with a weight over night.

Lock Helmet in Place ;

  • Outline helmet overhang [ picture 8 ].
  • Use the same narrow tool from fitting the helmet to cut an edge around the head hole [ picture 9 ].
  • When it locks and holds the helmet steady, glue all the layers together in place overnight.

Trim Hole to Slide Head ;

  • Finally we make the knife tool # 3 [ see picture 12 ].
  • Drill another hole in the wood dowel end.
  • Move the end of the weld-rod to the hole to make the knife.
  • Use this hot tool to trim out the head hole [ picture 13 ].

And .. It .. FITS !!!

[ see the last two pictures ].

Eye holes are made with a warm soldering iron...


For this step I used a wood frame laying around my shop.


  • Drill a hole 8" from one side top and bottom to slide the wire through.
  • Attach the split bolt wire connectors top and bottom.
  • You have to expect to set the variac to a higher 50 dial setting.
  • Here is a video by the Captain of Light.

And one more video by the Captain of Light

shows the pretty green variac and the smoke collecting up in the ceiling.



  • To cut the TOP shapes outlined in [ picture 2 ].
  • Lay the mask on its side.
  • Cut the SIDE shapes outlined in [ picture 3 ].

Use the KNIFE TOOL # 3

To cut the EYE slots [ see pictures 5 thru 9 ].


  • Referring to the [ last four pictures ].
  • The blue LED strip glue side is pressed against the top eye slot.
  • But first the LED strip is passed through the nose bridge.
  • Run the wires over the top of the helmet using a hanger wire.


Making the Simple HAND CONTROL ;

Don't Panic, there are only four or five components on the HAND CONTROL.

The Hand Control uses a 9volt battery and has two switches and one diode [ see picture 1 ].

The slide switch turns the LEDs ON / off.

The push button makes the LEDs get Emotionally BRIGHTER when pushed !

See how it works.....

You can use cheep battery snap wire clips and cardboard in place of the fiberglass I used.

Any switches will work and tape and rubber bands will hold things together.

use low cost speaker wire for the LEDs.

TIP don't keep loose change in the same pocket as the Hand Control.

TIP don't use spray paint as it actually devolves the styrofoam.

Make it Glow!

Participated in the
Make it Glow!

Enchanted Objects

Participated in the
Enchanted Objects

Halloween Costume Contest

Participated in the
Halloween Costume Contest