National Clothesline
National Clothesline
Solving problems using acids
Acids are defined as chemicals that release hydrogen ions in the presence of water.
Different acids are similar in characteristics but do not react the same on all problems. Different acids react differently on staining and used in conjunction with other chemicals.
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Acid characteristics
Soluble in water and wetside chemicals.
Has a PH under 7; the lower the number the stronger the acid.
Used for tannin stain removal.
Used to set dyes.
Chemically the opposite of alkali.
Used to restore color change caused by an alkali.
Speeds up reducing bleaches and some oxidizing bleaches.
Used in wetcleaning to set many dyes.
Heat accelerates and makes the acid stronger.
Tannin formulas
These are mild acids mixed with a neutral lubricant. They usually have the PH of 5.5 which makes them safe for colors and fabrics. They are not affected in neutralizing color change caused by alkali.
Acetic acid
This acid comes in different strengths. The safest strength to purchase this acid is 28%. For effective use it should be diluted to 14% which reduces the odor that is characteristic to this acid.
When acetic acid is heated or used in stronger strengths it can affect acetic fabrics.
Oxalic acid
This comes in powder form and can be mixed 1 part oxalic to 20 parts water. It is also sold by manufacturers as a safe rust removing agent.
This is not an entirely safe acid to use and should be tested before use.
Hydrofluoric acid (rust remover)
This is the strongest acid, even though it is diluted to a weak strength. This acid is difficult to rinse from a fabric and should be neutralized with a mild alkali after use.
It cannot be used on glass or metallic trimming. Do not use it on a glass or metal spotting board. This is the most effective acid for removing rust and also most effective in conjunction with certain bleaches. Test for color safety before using.
Problem solving
Some fabrics have a sensitivity to alkali and will change color. Animal fibers are most sensitive to alkali. If a color change occurs, flush the area thoroughly and then apply acetic or oxalic acid. Flush the area again.
Wine stains. The most effective acid for wine stain removal is acetic acid. It will work better than regular tannin formulas. Flush the area and then apply neutral lubricant and acetic acid. Tamp the area and then flush.
Last traces of dye and tannin stains work well with oxalic acid. Many manufacturers only sell oxalic acid as a safe rust remover. This acid can be applied after testing color to a dye or tannin stain and heated with a light feather of steam. The area is then flushed.
Delustering. Many acetate fabrics can deluster from a combination of water and steam. To correct the condition spray on a 14% acetic acid and let dry. Then dryclean the garment.
Dye setting for wetcleaning. The best and safest acid to use is 28% acetic acid. Add two ounces per gallon of water.
Stretching damaged leather. Sometimes a leather or suede that is steamed will stiffen and shrink. You can spray on 14% acetic acid and attempt to stretch it. Then apply a neutral oil spray.
Removing sodium hypochlorite. To remove the last traces of chlorine bleach after spotting or cleaning, use acetic or oxalic acid. This will accelerate and remove the last traces of chlorine.
Neutralizing sodium perborate. After rinsing, use acetic or oxalic for neutralizing. Then rinse again.
Potassium permanganate. The best acid to use to neutralize the discoloration from permanganate is oxalic acid or a combination of hydrogen peroxide and acetic acid.
Titanium sulphate. The best acid to use with this bleach is hydrofluoric acid. This not only accelerates the bleach but restores any color change that the bleach may have had with other chemicals.

Dan Eisen is the former chief garment analyst for the Neighborh