Question 1

A-Stage

Accepted Answer

An early stage in the reaction of certain thermosetting resins in which the material is fusible and still soluble in certain liquids.

Question 2

What is Double Mixing?

Accepted Answer

Double mixing involves mixing the A & B components thoroughly in one container and then transferring the mixture into a new, clean container. Double mixing leaves much of the unmixed material that hides in the corners and sides of the cup behind, ensuring a more thorough mixture. Unmixed material can show up in the part as soft spots or unsightly swirls/streaks.

Question 3

What is Cure Inhibition in Silicones?

Accepted Answer

Some materials can have chemical incompatibilities when poured into or up against other materials. For example, platinum silicones may show inhibition characteristics against natural rubbers, cyanoacrylates, tape residue, and sulfur based clays. Whenever in doubt, a small side test is always recommended.

Question 4

Adhesive

Accepted Answer

A substance capable of holding materials together by surface attachment. Note: Adhesive is the general term and includes, among others, cement, glue, mucilage and paste. All of these terms are loosely used interchangeably.

Question 5

Adhesive Failure

Accepted Answer

The failure at the bond line between substrates and an adhesive; the adhesive separating entirely from the substrate.

Question 6

What is Cured Inhibition in Urethanes?

Accepted Answer

Certain urethane systems may be affected by the type of silicone mold being used. Tin based silicones (condensation cured) are known to cause issues with Aliphatic urethanes. Platinum silicones (addition cured) are recommended for Aliphatic urethane. Silicone mold material must be carefully selected depending on the urethane system you plan to cast.

Question 7

Aggregate

Accepted Answer

A hard fragmented material used with an epoxy binder as a flooring or surfacing medium. Also a coarse filler used as a core for epoxy tools.

Question 8

Why do I Need to Mix Individual Components in their Containers?

Accepted Answer

Individual components in a container need to be mixed and/or stirred prior to weighing them out on a scale. With storage time and ambient temperature changes, ingredients can separate out and will need to be remixed. Filled, pigmented or fire retardant materials need to be pre-mixed before every use or the heavier fillers could settle to the bottom and cause curing problems.

Question 9

Aging

Accepted Answer

The change of a material with time under defined environmental conditions, leading to improvement or deterioration of properties.

Question 10

What is Pot Life vs. Gel Time?

Accepted Answer

Pot Life is the time you have from the moment you begin mixing to the point you can still easily pour material into a mold. Gel Time is the measurement of time when the material actually gels. As materials get higher in viscosity, they do not have optimum flow characteristics and may not produce as good a part. Always be aware of the pot life and gel time rating on any data sheet as well as the mass it is calculated at. Adding more mass (e.g. 400g vs. 100g) will shorten the pot life. Mixing an appropriate batch size can assure you have time to vacuum and pour your material. Always choose an appropriate pot life based on how difficult your cast is and how much material will be mixed prior to casting.

Question 11

How does Temperature affect Casting Materials?

Accepted Answer

Storage temperature can have a drastic affect on materials. Working time, demold time, viscosity, and physical properties of the material are all affected by temperature. In cold winter months working with thermal set systems (urethanes, epoxies, etc.) can be a problem. Materials tend to be much higher in viscosity. Higher viscosities can make mixing, degassing, and pouring as much of a challenge as brittleness can be when you demold. This is not the fault of the material; it is the nature of chemistry. Extra care needs to be taken to pre-warm materials prior to mixing as well as pre-warming of molds. Warm material poured into a cold mold can have undesired results, especially if the material has a long working time. Heat can work to your advantage if you need to process faster but it can also work against you. Pre-heating materials lowers viscosity, making it easier to mix and pour, but it also shortens your work time. Sometimes going with a longer pot life and heating the material can give you the benefit of lower viscosity without sacrificing valuable work time. Elevated temperatures can also increase the physical properties of a material. See Post Curing below for more details.

Question 12

Amine

Accepted Answer

Curing agent for epoxy resins that is any of a class of ammonia (NH3) derivatives.
Artificial Weathering - The exposure of product to cyclic laboratory conditions involving changes in temperature, relative humidity, and ultraviolet radiant energy, with or without direct water spray, in an attempt to produce changes in the material similar to those observed after continuous outdoor exposure. Note: The laboratory exposure conditions are usually intensified beyond those encountered in actual outdoor exposure in an attempt to achieve an accelerated effect.

Question 13

ASTM

Accepted Answer

American Society for Testing Materials.

Question 14

B-Stage

Accepted Answer

An intermediate stage in the reaction of certain thermosetting resins in which the material softens when heated and swells when in contact with certain liquids, but may not entirely fuse or dissolve. The resin in partially cured thermosetting system is usually in this stage.

Question 15

What is Post Curing?

Accepted Answer

Pre-warming a mold and or material will help the cure on the front end of a job, but what about after it has initially set up? Post curing at elevated temperatures can increase the physical properties of a material; tear strength, flexural strength, and heat distortion can benefit from a proper post cure. Some rigid materials may appear brittle upon demold after the initial cure. Post curing can assist the chemical cross linking to maximize the material’s physical properties above and beyond what can be achieved at ambient temperature over several days. Post curing is best done in an accurate, temperature controlled oven (never a household oven). Always refer to the TDS (Technical Data Sheet) for proper post curing conditions. Some materials can have undesired results at elevated temperatures (swelling, bubbles, deformation), so always check the recommended procedures.

Question 16

What is the difference between Aromatic and Aliphatic urethanes?

Accepted Answer

Aromatics are the most commonly used urethanes. They tend to be more economical to produce, have good physical properties, and range from low durometer elastomers to rigid plastics. Their down sides tends to be poor UV resistance and lower chemical resistance. The Aliphatic urethanes have outstanding UV stability, color stability, and chemical resistance. Their down sides tends to be longer gel and demold times, low heat distortion, low tolerance to colder casting temperatures, and higher material costs. Blends of Aliphatic and Aromatic urethanes can exhibit excellent UV resistance, good heat distortion, and good physical properties.

Question 17

Baking Temperature

Accepted Answer

A temperature above 150°F (65.6°C). Refers to curing materials at elevated temperatures.

Question 18

How Do I Work With Water Clears?

Accepted Answer

Aliphatic Water Clears are not tolerant of cold casting temperatures. Clarity and physical properties can be severely affected if cast below 70 degrees F. Molds must also be preconditioned to minimum temperature (75-85°F) or heat may be pulled from the curing material. Clear materials require a good vacuum system to pull the trapped air out of mixed material prior to pouring into a mold. Water Clears do not self-release entrapped air. Without pulling a vacuum on the mixed material, a cast part may end up looking more like a glass of carbonated soft-drink than a glass of crystal clear water. Casting the part in a pressure tank/vessel can also aid in reducing bubbles by compressing bubbles down to the point that they are not visible anymore (see Vacuum and Pressure). Casting in thin sections may also require additional heat to make up for the lack of internal exotherm (less mass equals less self- generated heat). Water Clears cure best if preconditioned to a minimum of 75-85°F range and a max of 100-110°F, keeping in mind that higher temperatures will shorten work life.

Question 19

Bonding

Accepted Answer

The union of materials by adhesives.

Question 20

Bond Strength

Accepted Answer

The unit load applied in tension, compression, flexure, peel, impact, cleavage, or shear, required to break an adhesive assembly with failure occurring in or near the plane of the bond. Note: The term adherence is frequently used in place of bond strength.

Question 21

How does Vacuum and Pressure affect casting materials?

Accepted Answer

When you are hand mixing casting materials, air bubbles are inevitably going to be stirred in. Viscosity, temperature, and surface tension of the material will determine how well the air will or will not self release from the liquid. Mixed material should always be placed in a vacuum chamber to remove air bubbles prior to pouring material into the mold; this process is called de-airing or de-gassing. Vacuuming the material expands the trapped air, causing the bubbles to grow and rise to the surface of the material for release. After a period of time these bubbles decrease in quantity, meaning that the air has effectively been removed from the material. Air can cause voids and potential mechanical issues with a cast part. Cold materials will have higher viscosities and may be more difficult to degas. Raising the temperature of the material lowers the viscosity, which will aid in pulling air out but may also reduce working time if overdone. Pressure casting can be an alternative or a secondary process to vacuum ‘degassing’ material. Pulling air out of the material ensures the material isn’t latent with bubbles as it goes into the mold, but air can be re-introduced into the material as it is poured in from splashing or from mold features that trap air, e.g. sharp corners. In some applications, vacuum and pressure must be used in conjunction to produce air-free parts. Typical pressure values are in the 40-50 psi range. Higher pressures may be required if material is not degassed. Pressure does not remove air; it compresses air bubbles down to the point that they are not visible anymore. If pressure is released too soon (before material has had time to set), the bubble, could potentially reappear.

Question 22

Brookfield Viscometer

Accepted Answer

An instrument for measuring the viscosity of formulated adhesives under standard conditions of temperature.

Question 23

Bubble

Accepted Answer

Internal void or a trapped globule of air or other gas.

Question 24

C-Stage

Accepted Answer

The final stage in the reaction of certain thermosetting resins in which the material is relatively insoluble and infusible. Certain thermosetting resins in a fully cured state are in this stage.

Question 25

Calorie

Accepted Answer

A thermal unit. A calorie is that amount of heat required to raise the temperature of one gram of water one degree centigrade.

Question 26

Catalyst

Accepted Answer

A substance which markedly speeds up the cure of a relative material when added in minor quantity as compared to the amounts of the primary reactants.

Question 27

Centigrade

Accepted Answer

A scale of temperature which features 0° and 100° as the freezing and boiling point of water respectively. To convert Centigrade to Fahrenheit, multiply by 1.8 and add 32, e.g., (100° x 1.8) + 32 = 212°F.

Question 28

Centipoise

Accepted Answer

1/100th of a poise; (dyne-sec/cm2); a viscosity measurement unit.

Question 29

Chalking

Accepted Answer

Formation of a dry powdery chalk-like appearance or deposit on the surface of a material. It is due to a breaking down of the material after being exposed to ultraviolet light or weathering.

Question 30

Clarity

Accepted Answer

Degree of clearness in a transparent material.

Question 31

Coefficient Of Linear Thermal Expansion

Accepted Answer

Once cured, a measure of the change in length of a material over a given temperature range. It is expressed in inches per inch per degree C. ASTM D696-44.

Question 32

Coefficient Of Thermal Expansion (CTE)

Accepted Answer

Change in a unit of length or volume that accompanies a unit change in temperature.

Question 33

Cohesion

Accepted Answer

The state in which the particles of a single substance are held together by primary or secondary valence forces observed in the tendency of the substance to stick to itself. As used in the adhesive field, the state in which the particles of the adhesive (or the adhered) are held together.

Question 34

Cohesive Failure

Accepted Answer

Failure within the adhesive under a stress, resulting in a broken bond with all adhered surfaces still covered with adhesive.

Question 35

Compressive Strength

Accepted Answer

Crushing load at the failure of a specimen divided by the original sectional area of the specimen. The maximum load in pounds that can be carried per square inch of cross section of the material under test.

Question 36

Compressive Strength, Ultimate"

Accepted Answer

The maximum load in pounds that can be carried per square inch of cross section of the material under test.

Question 37

Conductive

Accepted Answer

Having the quality or power of conducting or transmitting heat, electricity, or static electricity.

Question 38

Conductivity

Accepted Answer

Reciprocal of volume resistivity. Conductance of a unit cube of any material.

Question 39

Cross-Link

Accepted Answer

Tying together large molecules and hence changing the physical properties of material. Cross-linking usually involves formation of three dimensional molecular network and is customarily associated with thermosetting resins.

Question 40

Cure

Accepted Answer

To change the physical properties of a thermosetting material by chemical reaction through polymerization, usually accomplished in the presence of heat and catalyst, alone or in combination.

Question 41

Cure Cycle

Accepted Answer

The schedule of time periods at specified temperatures to which a reacting thermosetting plastic or rubber composition is subjected in order to reach certain specified properties.

Question 42

Curing Agent

Accepted Answer

A catalytic or reactive agent which when added to resin causes polymerization.

Question 43

Density

Accepted Answer

The ratio of a substance’s mass to its volume at a given temperature and pressure. Example: water at 25°C, 1 atmosphere of pressure = 1.0 gr/cm3 = 8.35 lb. per gallon.

Question 44

Dielectric Strength

Accepted Answer

The voltage which an insulating material can withstand before breakdown occurs, expressed in volts per mil.

Question 45

Dielectric Strength

Accepted Answer

The voltage which an insulating material can withstand before breakdown occurs, expressed in volts per mil.

Question 46

Diluent

Accepted Answer

A reactive or non-reactive additive whose primary function is to lower the viscosity and extend the material to which it was added.

Question 47

Dispensing Supplies

Accepted Answer

Medium used to apply liquid materials. Squeeze bottles, syringes, needles, and meter mix equipment are all examples.

Question 48

Discoloration

Accepted Answer

Any change from an initial color possessed by a material, either due to environmental or internal conditions.

Question 49

Domed

Accepted Answer

Term often used when clear "epoxy domes" are applied to labels, pins, magnets, key tags, etc.

Question 50

Elasticity

Accepted Answer

That property of materials by virtue of which they tend to recover their original size and shape after deformation. Note: if the strain is proportional to the applied stress, the material is said to exhibit Hookean or ideal elasticity.

Question 51

Elastomer

Question 52

Elongation (%)

Question 53

Encapsulation

Question 54

Evacuation

Question 55

Exotherm

Question 56

Extender

Question 57

Failure, Adhesive"

Question 58

Failure, Cohesive"

Question 59

Failure, Substrate"

Question 60

Filler

Question 61

Fisheye

Question 62

Flame Retardance

Question 63

Flash Point

Question 64

Flexural Modulus

High Performance Thermoset Materials
Engineered to Meet Challenging Production Requirements

Epoxy • Polyurethanes • Polyureas • RTV-2 Silicones • Miscellaneous • Private Labeling

NEW

Proxitane® Disinfectant

Glossary

High Performance Thermoset Materials Engineered to Meet Challenging Production Requirements

Epoxy • Polyurethanes • Polyureas • RTV-2 Silicones • Miscellaneous • Private Labeling

NEW

Proxitane® Disinfectant

Glossary

High Performance Thermoset Materials
Engineered to Meet Challenging Production Requirements