A tannin is the main part of a rust converter. These products can now be easily found in hardware and auto parts stores. When shopping for your product, remember you may get what you pay for. Look for a pH of 2 to 2.5 for effectiveness. Check the shelf life and make sure the product is still well mixed and has not settled.
Rust converters are only highly effective if used properly.
The rust converter can be brushed or sprayed on. The temperature of the metal should be between 50 and 90 degrees F., and there should be no threat of rain for at least 24 hours. The reaction will begin within 20 minutes and be complete in about 24 hours. Here are some hints for finding and using garden and architectural pottery. The condition, age, color, and patina are key factors in determining price and desirability.