Rotodip

The rotodip was a process used by BMC to coat both vehicle bodies and other metal items not welded to body with a special rust proofing agent.

All Mini, 1100 & 1800 bodies were rotated through the rotodip during the painting process. Allowing primer to take to normally inaccessible areas. The bodies complete with doors, bonnets and bootlids were fully immersed and were rotated a six - stage phosphating machine.

The bodies had a large rod inserted through the grille cutting, and through the remove able panel in the bulkhead, before the rod came out through the boot opening. The body was clamped to the rod so that there was no movement while the process was being carried out.

In the first stage the bodies were dipped in a tank which had a heated alkali solution to remove any oil and other contaminants picked up during the building process. The second tank was filled with cold water to rinse off the alkali solution. The third tank contained hot water, which ensured that the body was perfectly clean before it entered the phosphating tanks. If there was any contamination left on the bodies then the rust inhibiting solution wouldn't be as effective.

After the initial stages the bodies would then be run through the phosphate solution. High pressure jets sprayed the solution into every inaccessible area of the body. The phosphate solution acted as an anti rust agent, so that if the body was accidentally damaged it would stop rust coming through, and it also acted as a bond so that the paint would take to the steel. After this processing the bodies were once again washed off in a tank of warm water to clean off any excess. After the wash the body was placed in an oven to dry the solution before being coated in primer.

The painted bodies were then moved to a oven, where they would baked for 30 minutes at 171 degrees Celsius.


In the background an 1100 is ready to begin its rotodip. While in the foreground, an employee prepares an 1100 to begin its journey on the rotodip.