Summary of the Masking Materials Study

Transcription

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?
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• 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
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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
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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
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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
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• Compressed air
Determining the Success of Masking Materials
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• 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 –
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almost the entire l
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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
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•
•
•
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Stop Galv
Stop
Galv
Maskote Zinc Stop‐Off
NAPA RTV Red
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Galva Stop
GE 100% Silicone Caulk
Valmont Masking Compound
Valmont Masking Compound
Phase 1 Testing – Successful Materials f
for Buried Threaded Holes
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•
•
•
•
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DAP Household Adhesive Sealant
DAP
Household Adhesive Sealant
GE 100% Silicone Caulk
Valmont Masking Compound
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Maskote Zinc Stop‐Off
Macropoxy 846
ZYP Boron Nitride Hardcoat
ZYP Boron Nitride Hardcoat
Phase 1 Testing – Successful Masking Materials for Bolt Threads
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•
•
•
•
•
•
Galva Stop
Galva
Stop
Stop Galv
DAP Household Adhesive Sealant
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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
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• 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
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1 Hour Cure Time:
1
Hour Cure Time:
• Stop Galv
• Galva Stop
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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
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through the masking materials and gouged the steel below.
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Phase 2 Bolt Thread Testing ‐
Successful Masking Materials
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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
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• 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
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•
•
•
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Stop Galv
Stop
Galv
GE 100% Silicone Caulk
Maskote Zinc Stop‐Off
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Off
NAPA RTV Red
Galva Stop
DAP Household Adhesive Sealant
DAP Household Adhesive Sealant
Questions?
Additional Information About Masking Materials
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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
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bduran@galvanizeit.org
720‐554‐0900 x 21