Round Blade Construction

These are basic instructions for creating a safe “boffer” weapon using pipe foam, tape, and other materials.


Foam for the Blade:  This needs to be at least ⅝” thick foam.  It should be somewhat stiff, but compress a bit and return well.  Most chain hardware stores do not stock ⅝” foam in the southeast.  Sometimes, Ace Hardware does.  Another source is McMaster-Carr.  They are a hardware supplier, and can be found online at .  From there, you are looking for Semi-slit Flexible Polyethylene Foam Rubber tubes, found on this page:

Since they do not have ⅝” thick insulation, get the ¾”.  The ID you want is likely ½” (that depends on your core selection, see below), which means using part number 4530K162.  Shipping can be a little costly depending on your area, so ordering several in a batch is recommended.

Rigid Core:  This is the material at the center of the weapon.  There are two options with this:  PVC pipe or Kite spar.  You want a piece that is 5” shorter than the weapon you are making.

PVC Pipe:  This can be found at your local hardware store.  For weapons up to longsword in size, you can use ½” PVC pipe.  Longer weapons require ¾” PVC pipe (note that you will need a larger ID of insulation for this).  Shortswords and smaller can use CPVC – it is more flexible, but can work for short weapons still.  Best way to pick out your pipe is to cut a 2-3” long section off the piece of foam you ordered, and take it to the hardware store.  Then test it versus the different PVC pipes they have there (check in the Plumbing and Electrical areas).  You want a snug fit for it.  A little loose is acceptable, but the foam should not slide freely.

Kite Spar:  Used in building the framework for kites, kite spar is fiberglass tubing that has alternating layers of fiber running down the length and wrapped around it.  Ordering online is the best source for this. has a good selection, found here: .  For the ½” ID pipe foam, you should use 0.602 core.  This is because the ½” foam has a larger than 0.5” inner diameter.  If making a shortsword or smaller, you can use ⅜” ID foam and 0.414 core.

Things to Avoid:  Carbon Fiber or Fiberglass tubing (where the fibers all run the length of the core) – these can break on impact.  Copper or Aluminum tubing – heavy, and can be bent out of shape.  Thinwall PVC – it is hard to gauge this, but in general if the wall of a PVC looks thin, it might break, especially in cold weather.  If there is a PSI rating, 400 and above is usually good.  200 may be too low.

Squishy Foam:  This is soft foam used for the thrusting tip at the end of the weapon, and for the end-cap below the handle.  The best source is usually craft stores (Jo-Anns, Micheal’s, Hobby Lobby), look for the upholstery section for chair pads.  You want foam that squishes easily and recovers fast.  It needs to be 2” thick.

Tape:  Tape is used for reinforcing the joints, protecting the foam from impacts, wrapping the handle, and giving the weapon an appropriate color

Duct Tape:  This is the most common used tape.  It can be used for reinforcing joints, but mostly is for covering the whole weapon.  You don’t want stuff that is too thick, or so thin that it is translucent when applied.  This can be used for wrapping a handle, but doesn’t feel great.

Electrical Tape:  Not good for anything but wrapping handles.  The adhesive gets gummy over time usually.

Strapping Tape:  Good for reinforcing joints.  Not good for anything else.

Round Blade Construction Great for covering the weapon and for reinforcing joints.  Much more expensive than other tapes (check here to order it online: )

Things to Avoid:  Foil tapes.  Cheap duct tape.  ‘Contractor grade’ duct tape.  Packing tape.  Masking tape.

Assembly Instructions


  • Decide the overall length of the weapon you want to make.  Usually the weapon length is in the rules for the game you are making the weapon for.
  • Subtract 4.5 inches.  This is the Core Length.
  • Many games also have a limit on the size of the handle or blade.  You can decide this now are after preparing the core.  Remember that the Thrusting Tip will add 2” to the blade length.

Core Prep

  • Measure the Core Length on whatever core material you are using.
  • Cut to that length.  Use a hack saw if cutting kite spar, and avoid breathing in the dust.
  • Foam end-caps on the core
  • Option 1:  Cap the core with tape and then cut a 1” long piece of foam the same diameter as the core.  Wrap tape around the foam so it is less flexible, but not so much that it is stiff.  Strapping tape can reinforce this.  Repeat on the pommel end, using a ½” thick piece of foam.
  • Option 2:  Cap the core with a wood button and tape down.  Finish as option 1.  You may need to shorten the core length by 0.25” to account for the thickness of the wood buttons.
  • Option 3:  Insert 2”-3” of foam into the end of the core, then wrap with tape, and cut the foam off at 1” past the end of the core.  Repeat on the pommel end and cut off at ½” past the end of the core.  Tape wrapped this way should be over the core also.
  • If you did not decide on blade length, now is a good time.  Find on the core.