Instructables

Using Lasers with Paper Molds & Pewter (Bologna Sandwich Casting)

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Picture of Using Lasers with Paper Molds & Pewter (Bologna Sandwich Casting)
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Materials:
2 pieces • 6” x 6” • Plywood (or MDF or similar flat board material)
3 piece • 6” x 6” • Matte Board (or similar flat material)
Pewter
Double stick tape (depending on design)

Tools:
Laser (TechShop)
Hot plate & stainless steel measuring cup (for melting pewter)
C-clamp
Tray (pyrex is good, or a baking sheet)
Jewlers saw & #2 blades
Hand files

Prerequisites:
Laser Cutting & Etching SBU: LAS101 @ TechShop



Step One: Laser Time
• Use CorelDRAW and the laser cutter to cut the silhouette of your design, out of one 6” x 6” pieces of matte board.
     • Refer to your handout from your Laser Cutting & Etching SBU: LAS101 class, for the appropriate settings for your materials on the laser.
     • Make sure to leave at least a 1” border in design
     • Include a V shaped “sprue” for metal to be poured through. Should be 1-2” wide.

• Use CorelDRAW and the laser cutter to etch a texture or design, onto the two remaining pieces of 6” x6”  matte board.
     • Refer to your handout from your Laser Cutting & Etching SBU: LAS101 class for the appropriate settings for your materials on the laser.
     • Include a sprue!
     • Remember that what is etched into this mold will be raised in your metal casting.
     • Also, any text needs to be reversed.


Step Two: Casting
• Line up your matte board mold pieces. Use double stick tape if you have any “floating” pieces, or need to precisely line up multiple layers.
• Sandwich the matte board mold layers between the 6” x 6” pieces of flat board (plywood or MDF) & securely clamp together with at least 2 c-clamps. Position this entire set up in a tray of some sort (pyrex or baking sheet).

• Set your pewter in your measuring cup, your measuring cup on your hot plate & turn ON (pewter will melt around 400 F depending on the specific alloy).

• Gently shake measuring cup handle to check and see if pewter is molten. Once it is up to temperature it will evenly move as one liquid volume.

• When pewter is molten, pour in one SLOW & FLUID motion.
     • Position the measuring cup lip as close as possible to the sprue.
     • If you have a shaky hand, set up a wooden block or something to use as a hand rest.
     • Pour until the mold (including sprue) is completely full.


• Wait until pewter cools (about 10 minutes).
• Carefully open mold and enjoy your castings (or if they didn’t come out right, melt down & cast again)!
• Because pewter has such a low melting temperature this mold is re-useable! It even tends to work better after it warms up (by the 3rd casting or so).



Step 3: Finishing
• Use a jeweler’s saw with a coarse sawblade (#2) to cut off “sprue” (negative in mold) / “button” (positive in metal).
• Use a hand file to remove any “flashing” and clean up and necessary edges.


I made it at TechShop! Check out there website: www.techshop.com!


History:

When I was a student at the College for Creative Studies, Tom Madden taught me Bologna Sandwich Casting (BSC). Years later, unable to find any articles on BSC, I asked Tom if there wasn’t another name for it. He told me he wasn’t sure, but to ask Paul Mergan. I found Paul through the Michigan Silversmith Guild and he told me he came up with BSC after Fred Fenster inspired him by teaching him to cast ingots of Pewter in a folded piece of paper. Paul told me he wanted to show his own students the “magic” of casting pewter in paper, but with more controlled results. He devised away to cut (traditionally with an x-acto knife & jewelers saw) & and layer sheets of paper/board and cast into them. As him process became more and more complex, he started color coating his layers, and the “yellow” layer soon became the mustard, the “green” the lettuce and so on and so forth, until he named the whole process BOLOGNA SANDWICH CASTING.

Phew. I hope I did it justice.
fkinney5 months ago

where do you find pewter to melt down

dipiazza (author)  fkinney4 months ago

I buy mine from Armstrong Tool & Supply in Livonia, MI.

http://www.armstrongtoolsupply.com/casting-en/cast...

therealodd1 year ago
While this is a great guide, with out access to "Laser Cutting & Etching SBU: LAS101 @ TechShop" it's at a bit of a stopping point for the rest of us...
You could cut the cardboard the old-fashioned way.
TechShopJim2 years ago
I saw these actual pieces yesterday at TechShop Detroit (they are on display at the front counter for you to hold and play with). It is hard to see in the photos, but there are dozens of tiny TechShop logos on the front size of the human figure! I couldn't figure out how the heck they made these at TechShop until the front desk folks told me!

As I thought about it more, I realized that this is a very powerful technique! With the laser cutter and the use of indexed layers of illustration board, very intricate items can be made very quickly and easily and cheaply. Some ideas I have are clock mechanisms (working gears), rings (laser the illustration board and then wrap it around a form to create the sandwich, and pour the pewter into the cavity), and inlaid porcelain metal pins (using powder coating powder dissolved with acetone to fill in the low areas instead of glass for the color inlays, then let the powder coating powder dry and bake it at 330 degrees F, then grind the front surface flat and flush with a honing stone). You could also make printing plates and letters including half-toned photos directly from digital artwork for a letterpress printer with this technique. When I get home from vacation, I will try some of these methods and write them up as Instructables (giving derivative credit to this great Instructable from the TechShop Detroit crew)!
I did exactly this for my year 12 product design class. We used thicker (up to 10mm) mdf and I was able to recessed center to mine by instead of using the full depth mdf. I cut an identical piece using thinner (1/2 depth) mdf which I place in the centre (instead of the full depth piece) and when casted I could remove the wood that was embedded using a drill (set so that it doesn't go all of the way through) and scrape out the rest using a scriber. I then poured dyed polyester resin into the cavity and sanded the surface flush, this way I could have a colourful and decorative front and a strong solid pewter back.

Your designs are quite similar to mine and are very good, as it the whole instructable. I can put some pictures up if anyone's interested but it will take a day or so to put them up.
Cool! I'll have to try this sometime (well without the laser cutter anyway) by the way I checked out your etsy store, nice work. I wish I was that good
dipiazza (author)  mr.mountaineer2 years ago
Hey thanks! It's really encouraging to hear!
dreamberry2 years ago
This is really, really cool. Bologna Sandwich LOL!