Sealants (nfm)

primary use

substrates

cure time

shrink

total joint movement

comments

acrylic latex interior, non moving joints

porous

slow

yes

15%

5 -20 years, paint will help protect, no standing water

polysulfide single (all joints except traffic)

all

slow

yes

25%

5 - 20 years

polysulfide multi (all joints except traffic)

all

variable

no

50%

5 - 20 years

polyurethane single (all joints)

all

slow

no

50%

resists traffic abuse, 5 - 20 years

polyurethane multi (all joints)

all

variable

no

50%

resists traffic abuse, 5 - 20 years

silicone single (all joints except traffic)

all

slow

no

50%

will not accept paint 5 - 10 years

silicone multi (all joints except traffic)

all

variable

no

50%

will not accept paint 5 - 10 years

structural silicone single (all & glass ext.)

all

slow

no

50%

will not accept paint 20 years

structural silicone multi (all & glass ext.)

all

variable

no

50%

will not accept paint 20 years

CSPE chemical resist memb.or coating

porous

slow

yes

25%

5 - 20 years, resists water, chem & petroleum prod.

Chloroprene swimming pools

porous

slow

yes

25%

5 - 20 years see CSPE

non-skinning acoustic seals

porous

non

no

none

2 - 5 years do not paint

Butyl, water seal, small joint movement

all

slow

yes

10%

5 - 20 years, protect from UV & ozone

preformed resilient sealant

all

non

no

100%

up to 20 years all types of joints

TLV & other Safety Data on Paint & Cleaning Solvents

NOTES: (1) Relative evaporation time is the relative time required for the solvent to completely evaporate, based on an arbitrary value of 1.0 for ethyl ether. The higher the number, the longer the time required for evaporation. (2) Flash point is the temperature of the solvent in degrees F at which the solvent releases sufficient vapor to ignite in the presence of a flame. The higher the value, the safer the solvent with respect to flash point. (3) Explosive limits define the range of solvent vapor concentration in air for which the vapor could explode or ignite. Below the minimum concentration and above the maximum concentration, the vapor will not ignite. These values are expressed as the percentage of the solvent vapor in the total volume of vapor plus air. They are also called flammable limits. (4) Threshold limit values (TLV) were obtained from the American Conference of Governmental Industrial Hygienists (ACGIH), Threshold Limit Values for Chemical Substances and Physical Agents in the Workroom Environment. TWA is the time weighted average exposure limit for an 8-hour workday or a 40 hour week. STEL is the short-term exposure limit for a maximum 15-minute exposure. Both values are expressed as parts per million (ppm) of vapor per volume of air. The higher the value, the safer the solvent. These TLV's are ACGIH's recommendations; Occupational Safety and Health Administration (OSHA) limits may be lower.

relative evapo -ration time

flash point

°C

evaporative limits % by volume

threshold limit values

min

max

TWA

STEL

Acetone

4

-12

2.6

12.8

750

1000

Benzene

8

-12

1.4

7.1

10

32

Butyl alcohol (butanol) - skin

70

40.55

1.4

11.2

50

Carbon tetra chlro -ryde/skin

8

not flammable

5

Di-isobutyl ketone

150

60

0.8

6.2

25

Ethyl acetate

8

4.4

2.5

9.0

400

Ethyl (grain) alcohol (ethanol)

20

15.5

4.3

19.0

1000

Ethyl ether

1

Ethylene dichloride

10

Ethylene glycol monoethyl ether/skin

100

43.3

2.6

15.7

5

Ethylene -diamine/ skin

10

Ethylene glycol monoethyl ether acetate

32

54.4

1.7

nd

5

hi flash naphta (aromatic)

105

40.55

1.0

7.0

Isopropyl acetate

10

10

1.8

7.8

200

250

Isopropyl alcoholiso propanol/ skin

25

18.3

2.5

12.0

200

250

methyl alcohol (methanol) - skin

10

12.77

5.5

36.5

200

250

methylene chloride (dichloro -methane)

4

not flammable

50

methyl ethyl ketone

8

-1.1

1.4

7.5

50

75

methyl isobutyl ketone

20

18.33

1.4

7.5

50

75

mineral spirit (petroleum thinner)

150

40.55

0.8

7.0

refined kerosen

800

65.5

0.7

5.0

trichloroethylene

50

100

toluene - skin

15

7.22

1.3

7.0

50

turpentine

100

40.55

0.8

nd

100

VM & naphta

20

10

1.1

5.9

300

water

100

not flammable

xylene - skin

35

29.44

1.0

6.0

100

150

Commonly Used Metods for Surface Preparation for Coatings

Cleaning method

Equipment

Comments

organic solvent

solvent such as mineral spirits

removes oil & grease not readily removed by other methods; precautions must be taken to avoid fires & environmental contamination; local VOC regulations may restrict use

detergent, power washing

pumps, chemical sprayers, brushes

at pressures not exceeding 13.7 MPa, removes soil, chalk, mildew, grease & oil, depending upon coposition, good for smoke, stain, chalk &dirt removal

Acid

chemical sprayers & brshers

removes residual efflerescence & laitances from concrete after dry brushing; thoroughly rinse afterwoods

Chemical paint strippers

chemical, sprayers, scrapers, washing equipment

removes coatings from most substrates, but slow, messy & expensive may degrade surface of wood substrates

Steam

heating system pump, lines & nozzles

removes heavy oil, grease & chalk; usually used prior to other methods

Water blasting

high pressure water pumps, lines & nozzles

at pressure of 13.7MPa and above, removes loose paint from steel, concrete & wood; can damage wood or masonry unless care is taken; inhibitor generally added to water to prevent flash ursting of steel

Hand tool

wire brushes, chipping hammer & scrappers

removes only loosely adhering contaminants; used mostly for spot repair; slow & not thorough

Power tool

wire brushers, grinders, sanders, needle gums, rotary peeners, etc.

faster & more thorough than hand tools because tighly adhering contaminants can be removed; some tools give a near-whit condition on steel but no an angular profile; slower than abrasive blasting; some tools are fitted with vaccuum collection devices

Heat

electric heat guns

can be used to soften coatings on woods, masonry or steel, softened coatings are scraped away, torches should not be used

Abrasive blasting

sand, metal shot & metal or synthetic grit properled onto metal by pressurized air, with or without water or centrifugal forces

typically used on metal & with care on masonry; can use recyclable abrasives; special precautions are needed when removing lead containing paint. Water may be added to control dust, so require use of inhibitors. Vaccuum blasting reduces dust but is slower than open. Centrifugal blasting is a closed cycle system in which abrasive is trown by a spinning vaned wheel.