This project is an intro to the concept of laser cut mold making. It will allow you to do a small test project before tackling the Intermediate Laser Cut Mold Project.
Skills gained and reasons for doing the Simple Project first:
1 - Test the etch settings on your particular lasercutter with PETG and folding joints
2 - Experience with taping a simple leak free joint
3 - Experience with entire process and concepts utilized with laser cut molds
1 - Laser Cutter
2 - 2x Mixing Buckets
3 - Paint Stir Stick
4 - Kitchen Scale (weighing out casting material and water)
5 - Funnel
6 - Exacto or Utility Knife
1 - Plaster of Paris or your preferred gypsum based casting material (We use Ultra-Cal)
2 - .030 or .040 PETG Sheet Approx. 10" x 10" (This gives about 1" margin on all sides)
3 - 6mm or .25" MDF Approx.. 10" x 10" (This gives about 1" margin on all sides)
4 - Duck Tape
Step 1: Laser Cutting Support Structure and PETG Mold
Download the SVG files for the sample cube mold and the sample cube support structure.
You will want to right click and select "save link as".
Sample Cube Mold
Sample Support Structure
Step 2: Assemble Support Structure
I found with this test piece that only the top support structure was needed (as seen in both photos)
Step 3: Fold and Assemble PETG Mold
By hand - fold PETG into shape and Duck Tape seams. Order of seam taping does not matter, but try to be neat about it as too much build up will cause it to not fit into the support structure and possibly leak.
Step 4: Mix Plaster and Pour into Mold
You will now weigh out the plaster powder mix and water (consult the bag/ or manufacturer for exact mix ratio) - I use two buckets and mix the powder into the water slowly while stirring. For a small piece such as this a paint stir stick works well to mix plaster.
The set up time will depend on the plaster product you use and the ratio of water to mix. We used Ultra Cal with it's recommended ratio - this gave us about a 40 minute working time before it set up.
Step 5: Remove Part from Mold
Allow proper curing time - then remove part from mold. Part should literally fall out when you turn it upside down.