13. Molding & Casting¶

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This week’s group assignment was to;
- Review the safety data sheets for each of our molding and casting materials
- Make and compare test casts with each of them.
- * extra credit: try other molding and casting processes
- Compare printing vs milling molds

Have you answered these questions?
- Documented how you designed and created your 3D mold, including machine settings
- Ensured our mold has smooth surface finish, that does not show the production process (by postprocessing if necessary)
- Shown how you safely made your mold and cast the parts
- Described problems and how you fixed them

Test Casting¶

Materials¶

These were the materials we tried and their safety information;

Material	Ferris File-A-Wax Blue	MOLD STAR 16 FAST	Smooth-Cast 300	Smooth-Cast 325	SORTA-CLEAR 37	Ecoflex 30
Pot Life		6m	3m	2.5m	25m	45m
Cure Time		30m	10m	10m	4h	4h
Shore		16A	70D	72D	37A	00-30
Characteristics						Food Safe
Process Memo
SDS	SDS	SDS/TB	SDS/TB	SDS/TB	SDS/TB	SDS/TB
Skin Corrosion/Irritation	Burns if molten	N/A	2	2	N/A	N/A
Skin Sensitization	N/A	N/A	1	2	N/A	N/A
Eye Damage & Irritation	N/A	N/A	2B	2	AN/A	N/A
Toxicity Inhallation	N/A	N/A	4	14
Respiratory Sensitization	N/A	N/A	1	1	N/A	N/A
Carcinogenic	N/A	N/A	2	2	N/A	N/A
Target Organ Toxicity (single exposure)	N/A	N/A	3	3	N/A	N/A
Target organ toxicity (repeated exposure)	N/A	N/A	2	2	N/A	N/A
Other	-	N/A		Harmful to aqutic animals	N/A	N/A

Safety Precautions¶

How to Read SDS, for beginners

PPE: Wear Apron, gloves, glasses
Environment: Large, well-ventilated room
Practices: Wash hands well with soap in case of contact with materials

Test Casting Workflow¶

(1) Smooth Cast300¶

Mixing: Easy to mix, but need to care about not having bubbles Needed to be mixed soft and slowly.
Cure Time: Suddenly got warm and became A bit late to take out a chopstick and made shape like soft cream.

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(2) Smooth Cast325
¶

Produces bubbles. Reacts with heat. Sets hard.
Air bubbles tend to remain after setting.

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(3) Sorta-Clear37
¶

Food safe. Elastic.

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The material used this time may have been old. Perhaps that’s why it took a lot of force to mix. New materials might be a little smoother(?)

Bad mold
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(4) Mold Star16 Fast
¶

Mix the white and blue solvents until the color is uniform.
Very smooth and easy to mix.
The work must be completed within 6 minutes.

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(5) Eco Flex
¶

Very smooth and easy to mix.
The reaction is slow and the color does not change, so it is difficult to tell if it is mixed.
However, it reacts with bubbles over time.
Even if there are air bubbles, most of the bubbles will be gone after it sets.

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