PaintSquare.com


The First Word in Protective & Marine Coatings

A Product of Technology Publishing / PaintSquare
JPCL | PaintSquare News | Durability + Design | Paint BidTracker

Get Paint BidTracker's Water Facility Painting Opportunities of 2015

Common causes of blister and bubble formation in industrial coatings

From JPCL, July 2014

More items for Quality Control

by James D. Machen, PCS, KTA-Tator, Inc. and Rich Burgess, KTA-Tator, Inc., Series Editor

...
(Login to read the full article)

   

Tagged categories: Blistering; Coating failure; Failure analysis

Comment from Tim Race, (9/9/2014, 10:28 AM)

"In other instances, bubbles can form in coatings due to cooler temperatures or high relative humidity during application. When application occurs during cooler temperatures or elevated humidity, the drying and curing of the coating film is slowed considerably. As a result, the proper release of solvents from the film does not occur. Consequently, if the next coating layer is applied too soon, the solvent in the underlying film becomes trapped and bubble formation can occur." Unfortunately it is a commonly held and incorrect belief that the drying rate of a coating containing only organic solvents is effected by RH. Unlike waterborne coatings, the drying of solvent-borne coatings is not effected to a significant degree by RH. High RH can result in blushing if moisture condensation occurs as a result of evaporative cooling of a solvent-borne coating. I suppose in theory it might be possible that someone could paint over the condensed moisture and hence blistering could occur. However, this is not the mechanism presented in the paper. The described blister mechanism can only occur in latex coatings and then only if coalescent solvent diffusion is retarded by a relatively low temperature (warm enough for water evaporation but not coalescent diffusion) and the coating is subsequently exposed to a sudden and significant temperature increase. This is especially true if the coating contains too much coalescent and if the coating is applied too thick. The failure mechanism is altogether different for latex and waterborne epoxy coatings that have been topcoated too soon after application at high RH. The retained water retards curing. In the case of a latex this means that proper film formation (coalescence) may not occur. The epoxy may cure but will have very poor mechanical properties. An analogous situation occurs when a solvent-borne epoxy is cured without sufficient ventilation. The relatively high partial pressure of evaporated solvent can retard further solvent evaporation from the film leading to a cured coating with poor mechanical properties (high internal stress/brittle/shear related adhesion failures).


Comment from kv g, (10/15/2014, 8:04 AM)

Could you explain the cases of blisters formed from the bare metal (sweep blasted surface of hot dip galvanised) noticed after the final coat curing (System is 2 coat High Build Epoxy follwed with one coat PU). Please respond. Regards gk


Comment Join the Conversation:

Sign in to our community to add your comments.

KTA-Tator, Inc. - Corporate Office
KTA Analyzes
Coating Failures

• Field Diagnosis
• Lab Diagnosis
• Determination of Cause
• Recommendations
www.kta.com
800-245-6379


Fischer Technology Inc.
MP0R with rotating display screen

View your coating thickness readings from any angle with rotating display screen. New graphic display with easy menu navigation. Click for Video
Call 800-243-8417


Elcometer, Inc.
Elcometer 266
DC Holiday Detector

Easily Finds Pinholes, Flaws & Thin Spots; Safer, More Reliable Testing; Voltage-Adjustable Keypad; Dual-Safety Switch On Handle.


DeFelsko Corporation
PosiTector Dew Point Meter

Measures and records
environmental conditions
during surface prep and
painting. 4 Models
Available – Standard
or Advanced features,
Built-in or Separate probe.


Corrosion Probe, Inc.
From Detection to Correction

Corrosion Probe, Inc. has the Most Concrete Coatings Experience and Expertise. Contact us today at
860-767-4402, www.cpiengineering.com


Minerals Research & Recovery

HIGH PERFORMANCE ABRASIVES


“Made in the USA!”

Why recycle waste from other countries? Go FASTER, CLEANER, at 1/3 THE COST with MR&R “All-American” Sharpshot®HP!!

WATCH THE VIDEO


Advanced Recycling Systems
ADVANCED RECYCLING SYSTEMS (ARS)

Recycling Machines, Dust Collectors, Rapid Deployment units are time-tested and approved for the rugged industrial environment. Contact ARS today!
(330)536-8210

 
 
 
 
Technology Publishing

The Technology Publishing Network

The Journal of Protective Coatings & Linings (JPCL) PaintSquare
Durability + Design Paint BidTracker JPCL Europe

 
EXPLORE:      JPCL   |   PaintSquare News   |   Interact   |   Buying Guides   |   Webinars   |   Resources   |   Classifieds
REGISTER AND SUBSCRIBE:      Free PaintSquare Registration   |   Subscribe to JPCL   |   Subscribe to PaintSquare News
MORE:      About PaintSquare.com   |   Privacy policy   |   Terms & conditions   |   Site Map   |   Search   |   Contact Us
 

© Copyright 2000-2014, Technology Publishing / PaintSquare, All rights reserved
2100 Wharton Street, Suite 310, Pittsburgh PA 15203-1951; Tel 1-412-431-8300; Fax 1-412-431-5428; E-mail webmaster@paintsquare.com