Deck 31: Removing Various Stains From Masonry Walls

Question 1

Most of the time, efflorescence cannot be removed with only water and a scrub brush.

Answer 1

False

Question 2

Silicic acid scum creates a grayish-white haze on the face of brick, which is referred to as _____ .

A) gray scum
B) white scum
C) efflorescence
D) smoke stains

Answer 2

B

Question 3

Use a cloth saturated with gasoline to remove an asphalt or tar stain that has not completely dried.

Answer 3

False

Question 4

Fresh paint can be removed using a solution of _____ .

A) oxalic acid and water
B) trisodium phosphate and water
C) ammonium bifluoride and oxalic acid
D) ammonium chloride and talc

Question 5

_____ stains are usually difficult to remove and should be scrubbed with a scouring powder, preferably one containing bleach.

A) Smoke
B) Iron
C) Oil and tar
D) Plant

Question 6

Green-stained brick often show no sign of a stain until they are _____ .

A) scrubbed with soap and water
B) soaked in rain water
C) washed in an acid solution
D) exposed to salts in proprietary cleaners

Question 7

Generally, _____ refers to a white, powdery substance on masonry walls.

A) efflorescence
B) vanadium stains
C) manganese stains
D) iron stains

Question 8

A masking solution of _____ can be used to darken lighter color brick.

A) oxalic acid crystals and water
B) hydrochloric acid
C) hydrogen peroxide
D) paraffin oil and Varosol

Question 9

For particularly difficult stains, spike the cleaning solution with larger doses of the cleaning solution than the directions recommend.

Question 10

Permanent removal of manganese stains is simple.

Question 11

Masonry cleaning products can be corrosive and toxic in nature.

Question 12

The proprietary cleaner, SURE KLEAN 600 should be mixed _____ water (by volume).

A) 1 part to 15 parts
B) 1 part to 12 parts
C) 1 part to 10 parts
D) 1 part to 5 parts

Question 13

Manganese stains occur on mortar joints and are typically _____ .

A) green streaks
B) white, powdery looking stains
C) black and tarry stains
D) brown and have an oily look

Question 14

To remove _____ stains, mix together 1 part ammonium chloride or sal ammoniac and 4 parts powdered talc.

A) welding splatters
B) dirt and paper
C) copper and bronze
D) egg splatter

Question 15

To remove green stains from a wall, spray the wall with _____ .

A) a muriatic acid solution
B) water
C) a solution of potassium or sodium hydroxide
D) a solution of acetic acid and hydrogen peroxide