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Summary of the Masking Materials Study
Summary of the Masking Materials Study AGA Tech Forum 2010 Presentation By Bernardo Duran By Bernardo Duran Corrosion Engineer, AGA What is a masking material? What is a masking material? Masking materials are products applied to steel Masking materials are products applied to steel in specific areas prior to hot‐dip galvanizing to prevent zinc from reacting with and adhering prevent zinc from reacting with and adhering to the steel. Masking materials are also called stop‐off stop off materials. materials Why are masking materials applied to steel that will be hot‐dip galvanized? l h ll b h d l d • Large Large areas of steel that will be welded areas of steel that will be welded • When precise fit of threaded areas cannot accommodate the additional width of the accommodate the additional width of the galvanized coating • Faying surfaces F i f AGA Masking Materials Study AGA Masking Materials Study • Masking Masking materials are commonly used and materials are commonly used and galvanizers and fabricators often ask which products work best products work best. • No study had looked at the effectiveness of the various products used as masking the various products used as masking materials. AGA Masking Materials Study Consisted of Two Phases d f h Phase 1 Testing: Phase 1 Testing: To determine the effectiveness of various materials used to mask steel surfaces from materials used to mask steel surfaces from zinc. Phase 2 Testing: Phase 2 Testing: To determine how successful masking materials work when given shorter cure times and work when given shorter cure times and determine if the original appearance of the steel can be restored after cleaning. Phase 1 Masking Materials Phase 1 Masking Materials • Duct Tape • Kapton Tape • VHT Header Paint (tested only on flat plate) only on flat plate) • Dow Corning Compound #111 • DAP Household Adhesive DAP H h ld Adh i Sealant • Stop Galv • NAPA RTV Red • GE 100% Silicone Caulk • Galva Stop • Valmont Masking Compound • Macropoxy 846 • 3M High Temperature Al i Aluminum Tape T • Maskote Zinc Stop‐Off • ZYP Boron Nitride YP oron Nitride Lubricoat • ZYP Boron Nitride Hardcoat Surface Types Testing In Phase 1 Surface Types Testing In Phase 1 Flat Plate Buried Threaded Holes Bolt Threads How the Masking Materials Were Applied / Removed in Phase 1 Testing l d/ d h Application: • Plates – foam brush • Buried threaded holes – Buried threaded holes – poured into holes poured into holes • Bolt Threads – dipped into material or spread with a foam brush with a foam brush Removal: • Metal‐bristled brush M t l b i tl d b h • Compressed air Determining the Success of Masking Materials k l • The The smaller the area that galvanized, the more smaller the area that galvanized the more effective the masking material. • Flat Plate – Flat Plate 90% of the surface area or greater 90% of the surface area or greater had to remain ungalvanized • Buried Threaded Holes – B i d Th d d H l almost the entire l h i hole needed to remain free of zinc • Bolt Threads – almost the entire threaded portion need to remain free of zinc Duct Tape Duct Tape Kapton Tape Kapton Tape VHT Header Paint VHT Header Paint Maskote Zinc Stop‐Off Maskote Zinc Stop Off Valmont Masking Compound Valmont Masking Compound NAPA RTV Red NAPA RTV Red GE 100% Silicone Caulk GE 100% Silicone Caulk Galva Stop Galva Stop Macropoxy 846 Macropoxy 846 ZYP Boron Nitride Lubricoat ZYP Boron Nitride Lubricoat ZYP Boron Nitride Hardcoat ZYP Boron Nitride Hardcoat 3M High Temperature Aluminum Tape 3M High Temperature Aluminum Tape Stop Galv Stop Galv DAP Household Adhesive Sealant DAP Household Adhesive Sealant Dow Corning Compound #111 Dow Corning Compound #111 Additional Pictures Additional Pictures Phase 1 Testing – Successful Masking Materials for Flat Plate l f l l • • • • • • Stop Galv Stop Galv Maskote Zinc Stop‐Off NAPA RTV Red d Galva Stop GE 100% Silicone Caulk Valmont Masking Compound Valmont Masking Compound Phase 1 Testing – Successful Materials f for Buried Threaded Holes d h d d l • • • • • • DAP Household Adhesive Sealant DAP Household Adhesive Sealant GE 100% Silicone Caulk Valmont Masking Compound l ki C d Maskote Zinc Stop‐Off Macropoxy 846 ZYP Boron Nitride Hardcoat ZYP Boron Nitride Hardcoat Phase 1 Testing – Successful Masking Materials for Bolt Threads l f l h d • • • • • • • Galva Stop Galva Stop Stop Galv DAP Household Adhesive Sealant h ld dh i S l NAPA RTV Red GE 100% Silicone Caulk Macropoxy 846 Macropoxy 846 Maskote Zinc Stop‐Off Phase 2 Testing ‐ Goals Phase 2 Testing • Determine Determine how the masking materials that how the masking materials that performed well in Phase 1 testing perform when given shorter cure times when given shorter cure times. • Determine if the original steel finish could be restored after removing the masking materials restored after removing the masking materials from the steel. Masking Materials Tested in Phase 2 Masking Materials Tested in Phase 2 • Stop Galv Stop Galv • Galva Stop • Maskote Zinc Stop‐Off Zinc Stop‐Off • NAPA RTV Red • GE 100% Silicone Caulk GE 100% Sili C lk • DAP Household Adhesive Sealant Not tested even though it performed well in Phase 1 Testing: Valmont Masking Compound Cure Times Tested Cure Times Tested Flat Plate: Flat Plate: • 1 hour • 2 hours 2 hours Bolt Threads: B lt Th d • 30 minutes • 1 hour • 2 hours Phase 2 Flat Plate Testing ‐ Successful Masking Materials k l 1 Hour Cure Time: 1 Hour Cure Time: • Stop Galv • Galva Stop G l S 2 Hour Cure Time: • Stop Galv Stop Galv • Galva Stop Phase 2 Testing – Cleaning Flat Plates Phase 2 Testing Cleaning Flat Plates • Simple Simple Green: had a negligible effect on Green: had a negligible effect on removing the debris left from the masking materials • G Grinder: The grinder immediately went i d Th i d i di l through the masking materials and gouged the steel below. h lb l Phase 2 Bolt Thread Testing ‐ Successful Masking Materials f l k l 30 Minutes Cure Time • Galva Stop • NAPA RTV Red 1 Hour Cure Time 1 Hour Cure Time • Galva Stop • Maskote Zinc Stop‐Off • DAP Household Adhesive Sealant DAP Household Adhesive Sealant • NAPA RTV Red • Stop Galv 2 Hour Cure Time All masking materials were successful, including GE 100% Silicone Caulk. Phase 2 Testing – Cleaning Bolt Threads h d • Simple Simple Green: A solution of 1 part Simple Green: A solution of 1 part Simple Green to 10 parts water and a nylon brush were used to scrub off the baked‐on were used to scrub off the baked on masking masking materials. The appearance was improved on all of the bolt threads with the various all of the bolt threads with the various materials. • Grinder: A grinder was not used because it can Grinder: A grinder was not used because it can damage the threads. Simple Green Cleaning Simple Green Cleaning List of Successful Masking Materials List of Successful Masking Materials • • • • • • Stop Galv Stop Galv GE 100% Silicone Caulk Maskote Zinc Stop‐Off k i S Off NAPA RTV Red Galva Stop DAP Household Adhesive Sealant DAP Household Adhesive Sealant Questions? Additional Information About Masking Materials l For detailed performance data please see the For detailed performance data please see the upcoming AGA Galvanizing Note – Masking Materials For Preventing Hot‐Dip Materials For Preventing Hot Dip Galvanizing. Galvanizing Contact Information: C I f i bduran@galvanizeit.org 720‐554‐0900 x 21
