What solvent is recommended for removing grease from aircraft fabric prior to doping it?

• A. Methyl Ethyl Ketone (MEK) or lacquer thinner.
• B. Water.
• C. Denatured alcohol.
• D. Acetone.

Answer: (A)

Cleaning the fabric surface to remove grease requires a solvent that dissolves oils effectively without swelling or damaging the fabric or the existing coating. Methyl ethyl ketone (MEK) or lacquer thinner are preferred because they rapidly dissolve grease and leave a clean, residue-free surface that’s ready for the dope to adhere properly. Their fast evaporation helps minimize any interaction with the fabric or sizing, reducing the chance of surface contamination that could weaken bonding.

Water won’t remove oil-based grease and can spread contaminants or cause unwanted moisture in the fabric, which is undesirable before applying dope. Denatured alcohol can remove some contaminants but isn’t as effective on heavy greases and may leave behind residues or interact with certain finishes. Acetone is a strong solvent, but it can be too aggressive for some fabrics and dope formulations, potentially affecting the surface and bonding.

So, using MEK or lacquer thinner provides the best balance of grease removal and surface readiness for proper bonding of the doped coating. Always work in a well-ventilated area and follow safety guidelines for flammable solvents.