Rust On Metal Using Alkyd Primers ||
Question: What is the proper procedure for treating metal roofs with rust prior to applying Galacti-Kote® Fibered Elastomeric Coating?
Answer: Using Alkyd Primers
Step I Wire brush to remove loose or heavily rusted and scaly area (all rust need not be removed).
Step II Make all necessary patching and repairs to prevent water from entering building during power washing.
Step III Remove oil and grease from metal with acetone, follow by soapy alkaline wash (T.S.P.). Then rinse with clear water.
Step IV In areas where there is extra heavy rust and where practical, for top performance sandblasting to white metal is recommended. For less severe exposures or where sandblasting is not practical, remove heavy rust by chipping, scraping, wire brushing and sanding.
Step V Power wash entire roof with clear water and let dry completely.
Step VI Over ferrous roof surfaces (iron & steel) use an alkyd metal primer that has rust-inhibitive pigments with special corrosion fighting alkyd resins which yield maximum rust protection and moisture resistance. Use Ponderosa Protective Coating #73 primer; apply at a rate of 250 square feet per gallon for a dry mil thickness of 2.5 to 3.0 mils. If surface is severely rusted go over with a second coat of primer.
Over galvanized roof surfaces use Zinc Chromate Primer. Use Ponderosa Protective Coating #75 primer; apply at a rate of 300 square feet per gallon for a dry mil thickness of 2.0 to 2.5 mils. If surface is severely rusted go over with a second coat of primer.
Step VII After the primer is thoroughly dry (at least 24 hours curing time) apply Galacti-Kote® according to Application Instructions.
Note: Before using these primers check with your local Air Pollution Control District (APCD) to make certain they are in compliance.
Rust On Metal Using Water Reducible Primers