Lec 9 Soldering (Intro)

Question 1

The joining of metal components by a filler metal, or solder, which is fused to each of the parts being joined.

Answer 1

Soldering

Question 2

If the filler metal has a melting temperature greater than 450°C (840°F), the process is called ________.

Answer 2

Brazing

Question 3

In ____________, the pieces that are joined are melted or fused together, without solder.

Answer 3

fusion welding

Question 4

Solder can be used for joining, as in the fabrication of a fixed partial denture, or it can be used for building, as when an addition is made to the proximal surface of a crown.

Question 5

Solder can be used for __________, as in the fabrication of a fixed partial denture, or it can be used for ___________, as when an addition is made to the proximal surface of a crown.

Answer 5

• joining
• building

Question 6

____________ is the prime prerequisite of soldering, inasmuch as the soldering process depends on wetting of the surface to achieve bonding.

Answer 6

Cleanliness

Question 7

____________ is the prime prerequisite of soldering, inasmuch as the soldering process depends on __________ of the surface to achieve bonding.

Answer 7

Cleanliness
wetting

Question 8

______________, such as oxides and sulfides, that are present as a result of the casting process or that occur on the surface of metals when they are heated interfere with bonding.

Answer 8

Corrosion products

Question 9

Placed on the surfaces to be soldered before they are heated. They may provide surface protection, reduce oxides, or dissolve oxides.

Answer 9

Flux

Question 10

Soldering fluxes for noble metals are based on ___________.

They form low-fusing glasses that protect the metal surface, and they also reduce oxides such as copper oxide. They often are too fluid for preceramic soldering.

Answer 10

borate compounds

Question 11

___________ are used on base metal alloys to dissolve the stable oxides of chromium, cobalt, and nickel. In addition to acting as solvents, these fluxes also serve a __________ role.

Answer 11

• Fluorides
• protective

Question 12

Flux is more easily applied if it is in _______ form.

Answer 12

paste form

Question 13

While a flux paste can be made with alcohol, the most popular form for use with noble metal alloys employs ___________ as a vehicle because it is more easily handled. It keeps air from the flux, and, when heated, the petrolatum burns off without leaving any residue.

Answer 13

petrolatum

Question 14

Fluxes made from common borax, or pastes made with water, tend to effloresce when they are heated, producing pits in the solder joint.

Question 15

Fluxes made from ________, or pastes made with water, tend to effloresce when they are heated, producing pits in the solder joint.

Answer 15

common borax

Answer 16

common borax

Question 17

Fluxes made from ________, or pastes made with water, tend to effloresce when they are heated, producing pits in the solder joint.

Answer 17

petrolatum

Question 18

Fluxes made from ________, or pastes made with ________, tend to effloresce when they are heated, producing pits in the solder joint.

Answer 18

common borax
water

Question 19

A material used to outline the area to be soldered in order to restrict the flow of solder.

Answer 19

Antiflux

Question 20

The most common antiflux is the mark of a ___________, which works best on surfaces that do not have a high polish.

Answer 20

soft graphite pencil

Question 21

Gold solders are classified by ________ and by _______.

Answer 21

fineness
carat

Question 22

refers to parts per thousand of the solder that is gold.

Question 23

refers to parts per thousand of the solder that is gold.

Answer 23

fineness

Question 24

Refers to parts per thousand of the solder that is gold.

Answer 24

fineness

Question 24

Refers to parts per 24 of a metal that are gold.

Answer 24

carat

Question 25

The actual noble metal content of the solder would be given by its __________ rather than by its carat.

Answer 25

fineness

Question 26

The higher the __________ of a solder, the higher will be its ________ and the greater its ____________.

Answer 26

fineness melting range corrosion resistance flow

Question 27

While a solder with a lower fineness has a lower melting range, it also has poorer ________ characteristics.

Question 28

While a solder with a lower fineness has a lower melting range, it also has poorer ________ characteristics.

Question 28

Refers to parts per thousand of the solder that is gold.

Answer 28

fineness

Question 28

____________ (iron oxide) suspended in chloroform can also be painted around the area of the solder joint to prevent undesired spread of the solder.

Answer 28

Polishing rouge

Question 29

The higher the __________ of a solder, the higher will be its ________ and the greater its ____________.

Answer 29

fineness melting range corrosion resistance

Question 30

While a solder with a lower fineness has a lower melting range, it also has poorer ________ characteristics.

Answer 30

poorer flow

Question 31

The minimum fineness that should be used is _____ fine, and a higher number would be better for preventing tarnish and discoloration.

Answer 31

580

Question 32

The solder should possess a fusion temperature that is about ____________ below that of the metal being soldered.

Answer 32

60°C (100 to 150°F)

Question 33

________ in solder is not desirable. More of it that occurs when there is an increased amount of ________ in the solder, which may vaporize when the gap between the components is too narrow or when the solder is over- heated.

Answer 33

Pitting base metal

Question 34

Solder should be as strong as the alloy with which it is used. The hardness of the solder decreases as the_________ increases.

Answer 34

fineness (gold content)

Question 35

The solder should flow freely. - _________ in the solder tends to make it adhere to metal and to flow more freely. - __________ makes it more sluggish. Solders that melt at _________ temperatures have a lower surface tension and flow easily through narrow gaps. ______- fusing solders flow poorly through narrow gaps.

Answer 35

- Silver - Copper - higher - Low

Question 36

____________ (iron oxide) suspended in chloroform can also be painted around the area of the solder joint to prevent undesired spread of the solder.

Answer 36

Polishing rouge

Question 36

Refers to parts per thousand of the solder that is gold.

Answer 36

fineness