This project builds on the skills learned in the Laser Cut Mold Simple Project.
NOTE: This table is 1/4 scale. 1/4" = 1"
Skills gained and reasons for doing the Intermediate Project:
1 - Next level of joint complexity
2 - Next level of casting complexity (working on getting out air bubbles/air pockets)
3 - Next level of scale
1 - Laser Cutter - 18" x 18 minimum bed size
2 - 2x Mixing Buckets (1 bucket needs to be larger than 1 gal. - 5 gal. works great)
3 - Drill with mixing attachment or stir sticks
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) (We recommend you use same material you used for first project)
2 - .030 or .040 PETG Sheet Approx. 22" x 38" (This gives about 1" margin on all sides) - Note the largest part is 18" x 18" with 1" margin on all sides
3 - 6mm or .25" MDF Approx. 24" x 27" (This gives about 1" margin on all sides)
4 - Duck Tape
Step 1: Laser Cutting Support Structure and PETG Mold
Step 2: 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.
My assemble order:
The top portion,
Attached the hollow to the top portion,
Each leg individually,
Finally attach the legs to the top portion.
The small skinny set-back portion on the leg will require great care when taping. My mold leaked in this place on all 4 legs due to poor taping =( however by packing towels around the leaks I was able to save the first try.
Step 3: Support Structure Assembly
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. The scale of this piece is right in-between hand mixing with a stir stick and a mixer attached to a drill. (We used a mixing paddle on a drill)
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.
I would highly recommend having a handful of rags handy when you cast. When casting with plaster based product you can actually pack the rags in-between the mold and support structure to help stop leaks if they should arise during the casting process.
Step 5: Remove Part From Mold
Allow proper curing time, then disassemble the support structure and un-tape the mold.