Casting and Molding: Urethanes Vs. Composites Quiz

Shore A Urethanes are great for making:

A) Soft pliable prototypes

B) Large, durable molds

C) Flexible molds with negative angles

D) Both A and C

When drilling a shore A urethane use:

The same size bit as the hole needed

A larger bit than the size of the hole needed

You can’t drill shore A urethane

Smaller bit than the size of the hole needed

A benefit to using Shore D Urethanes for molds over composites is:

It has a faster demold time than composites so you can produce parts quicker

It has higher tensile strength

It has better strength to weight properties

They don’t last as long

4. How long before 60 shore D urethane resins reach their maximum properties?

1 day

14 days

7 days

Immediately after demolding

What is the mix ratio of the 75 shore D:

1:1

2:1

3:1

4:1

75 Shore D parts can be demolded in :

2.5-3 hours

1-2 hours

6-8 hours

3-4 hours

When deciding between urethanes and fiber- reinforced plastics to create a mold, what should be considered?

Cost

Finished surface appearance

Both A and B

Neither A or B

Which casting urethane would be best to create a softer, more resilient part?

60 Shore D

75 shore D

40 shore A

None of these

Why do we NOT recommend wax and PVA release for urethane parts?

It takes too long to apply

They are water based and can cause bubbling or pitting

They work just fine with urethane parts

You don’t need a mold release

How can you limit moisture contamination when using urethanes?

Use plastic or metal stir sticks and containers

Use wooden mixing sticks

Use wax lined containers

Use paper containers

Casting and Molding: Urethanes Vs. Composites Quiz

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