Instructables

Wood Molds for Pewter Casting (I made it at TechShop)

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Picture of Wood Molds for Pewter Casting (I made it at TechShop)
With pewter's melting point being so low you can make molds out of lots of different materials. The following information will help you build a two part mold using a laser cutter and 1/4 inch thick wood. I used the laser cutter at my local TechShop. For more information on  TechShop look them up. http://www.techshop.ws
 
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Step 1: Draw the design.

Picture of Draw the design.
The shape of the cast piece can be drawn in any drawing software as long as the software can export a DXF file. The DXF file can be read into Corel Draw for the laser cutting.

Step 2: Draw a rectangle around the design.

Picture of Draw a rectangle around the design.
This rectangle will be the outside edges of the mold.

Step 3: Draw the sprue.

Picture of Draw the sprue.
Draw a funnel shape from an outside edge of the design to the outside edge of the rectangle.

Step 4: Draw two 1/4 inch circles in opposite corners.

Picture of Draw two 1/4 inch circles in opposite corners.
Making the circles a little smaller will allow you to use less glue later.

Step 5: Convert the design and the sprue into a raster image.

Picture of Convert the design and the sprue into a raster image.
The space being cut for the mold has to be a raster image for the laser cutter to cut it correctly.

Step 6: Set the rectangle and circles to the proper thickness.

Picture of Set the rectangle and circles to the proper thickness.
The rectangle representing the oputside surface of the mold and the alignment circles need to have their line thicknesses set to Hairline.

Step 7: Create the second half of the mold.

Picture of Create the second half of the mold.
Mirror the entire drawing to create the second side of the mold. You can leave the design the same or change it to create a different backside. Do not move the circles, Rectangle or sprue.

Step 8: Adjust holes on the second half of the mold.

Picture of Adjust holes on the second half of the mold.
Make the circles exactly 1/4 inch if you made the previous holes slightly smaller as suggested.

Step 9: Run the vector print to cut the mold out.

Picture of Run the vector print to cut the mold out.
Using the laser cutter print the raster design on a piece of 1/4 inch thick wood. (I used poplar.)

After the first time running the laser cutter measure the depth of the burned in design using a pair of calipers. It is best not to move or remove the board from the laser cutter while measuring the depth. If the desired depth is not reached after the first cut just press "Go" on the laser cutter to run the program again.

Once the design burned into the wood at the proper depth run the vector print to cut the mold out.
togo19191 year ago
Ummmm...

Cool Instructabus!

As for the Tigers. I was in Comerica Park one time in 2000. Loved the freshly grilled onions on the hot dogs!
Haven't tried this with my cnc router yet, but after seeing the results here, I will have a go! Nice work.
TomCloss (author)  stringstretcher1 year ago
I want to cut a few with the ShopBot. Need to plan for the diameter of the cutter so it wouldn't work with this design.
PKM1 year ago
I like it! It's always nice to see "outside the box" thinking about more things you can make with laser cutters. I guess you're going to sand the piece to make it smoother, but it looks like it's picked up the wood grain from the plywood and that could be a cool effect if you wanted it to look like that.
TomCloss (author)  PKM1 year ago
Actually the texture is from the laser itself. This was a solid board not plywood. I wanted the texture. I haven't tried this yet, but I might get a smoother result by changing resolution when cutting the mold.
Do you have any photos of what the mold was able to produce?

Thanks, aO
TomCloss (author)  audreyobscura2 years ago
Sure. I changed the last image to show the mold with a newly cast piece. To finish the piece you need to cut the sprue off and sand any out any rough spots.
The molded piece looks so nice! Will we get to see the pour process also? Thanks for a great pewter instructable.
TomCloss (author)  DIY-Guy1 year ago
I didn't add the pouring process since the focus of this intractable was the making of the mold. I'll create another intractable on pouring pewter soon. There are several methods I'll admit I use a poor mans version with a hot plate and a modified salt shaker.
sounds great!
Do you have any photos of what the mold was able to produce?

Thanks, aO