gingery_machines @Wiki patternmaking

Patternmaking

hand-built lostfoam patternmaking

• • use conventinal woodworking tools
    • design your part in a cad program, print out side front and top views, spray pattern with spray adhesive, cut out/drill along lines on printout with a bandsaw and drill press.
    • put an end mill or sanding drum in the drill press and pretend it's a milling machine. Move the foam billet around with your hands or against guides.
    • a disc or belt sander to remove large quantities of foam at once. it cuts down on the amount of dust formed since the foam is turned into dense powder instead of little foam bits
  • use hot wire cutter
    • i don't recommend using a hot wire cutter because it's inaccurate, leaves a crusty surface layer that can't be sanded off easily, smells bad, and gets stringy bits of melted foam everywhere. however, it is useful for certain things like making airplane wings and long "extrusions" like Dave Kush's HBLB's. It also cuts down on the amount of dust you have to deal with.

• • rubber cement (recommended)
    • Put a dab on, rub the two pieces together, take them apart and blow on them to speed up the drying, then when dry stick them back together for an instant bond. Make sure you stick it in the right place the first time! Requires fitting a more accurate joint than other methods, but it won't distort the joint either, since the glue film is so thin.
  • hot glue
    • put a light bead right on the joint, then smooth it out while it is still hot.
  • small bits of wire or toothpicks
    • "nail" the two pieces together with a short bit of wire. use aluminum wire if you are melting aluminum, brass if brass, etc.
  • PVA wood glue (Elmer's white glue)
    • Use cocktail sticks or weigh down to hold together. Allow to dry overnight. May not dry completely in the center of large joitns (i.e. laminating two sheets together) since the water is trapped inside.
  • Spray adhesive
    • tends to separate easily at the edges, makes a mess
  • double sided tape (not recommended)

• • scotch tape
  • paste wax mixed with styrofoam-sawdust in a syringe
    • lay down a bead like with a caulk gun, then spread it out evenly with a ball on a stick.
    • recipe: 25% beeswax, 25% toilet bowl ring wax, 5% solvent, (I use Old English lemon oil wood polish,) optional 45% styrofoam sawdust to reduce gas generation
  • already carved into form with a ball end mill
  • hot glue gun glue

CNC lostfoam patternmaking

greensand patternmaking

lostwax patternmaking

silicone molds for wax patterns