Eastwood's Internal Frame Coating destroys rust hiding inside the chassis, so it does not rust its way through. You spend all that time restoring a chassis, but what about the rust inside the frame rails? Eastwood's Internal Frame Coating has a tough phenolic resin that penetrates, converts and encapsulates the rust on the internal surface. Zinc phosphate seals it to prevent future corrosion. And the 24 inch long tube with conical nozzle reaches in to spray coating in a radial pattern for complete coverage.