What is the recommended practice for cleaning a fuel tank before welding?

The recommended practice for cleaning a fuel tank before welding is to steam clean the tank interior. This method is effective because steam cleaning can thoroughly remove contaminants such as dirt, grease, and fuel residue without leaving behind solvent residues that could ignite during the welding process. Additionally, steam cleaning helps to ensure that moisture is adequately removed, which further reduces the risk of combustion when welding is performed.

Using a solvent-based cleaner might not eliminate all potential flammable residues, as some solvents may leave behind a film or vapors that could ignite. Rinsing with gasoline is highly discouraged due to the significant fire hazard it presents, as gasoline is extremely flammable. Blowing out with compressed air can dislodge loose debris, but it does not effectively clean the tank or remove liquid contaminants, which can still pose a fire risk when welding. Therefore, steam cleaning is the safest and most thorough cleaning method to prepare a fuel tank for welding.