PaintSquare.com
      | Connect Follow us on Twitter Like us on Facebook
About | Subscribe | Advertise
  

 

Learn while you earn.

Problem Solving Forum

| More

April 16 - April 22, 2012

How long can a blasted surface be left before priming under different temperatures/relative humidity environments?



More items for Surface Preparation


Selected Answers

From remko tas of Futuro SRL on April 17, 2012:
     As a curiosity; flash rust did not occur for 10 days in a dry climate at an altitude of 4000m (13,000ft) in Bolivia, hundreds of kilometers away from the sea influence and contaminating industry. We could still safely paint the interior of the tank in one shot, achieving a high efficiency.

From Lubomir Jancovic of MSPLUB Inc. on May 1, 2012:
You have to prime the blasted surface of steel in up to 8 hours. Otherwise,  blasting was for nothing. If humidity is more like 60%, you have to prime the surface in up to four hours.

From Charles Williams of kurbtblast on April 16, 2012:
     Depending on the situation and coating system, we do not leave surfaces uncoated for more than 24 hours. Some epoxies have a tolerance level for flash rust (bloom), but when a zinc primer is required, we will coat the same day. Not all situations require same day priming, but some do. Our max time for leaving anything uncoated is 24 hours on warm dry days.

From Lee Edelman of Independant on April 19, 2012:

Always attempt to prime the prepared surfaces prior to the specified surface prep degrading. Most specifications will address this. Humidity and dew point should be monitored throughout the process, so that  when humidity or dew points exceed specification, there should not be any painting activities.

If the surface prep has degraded, most specifications will require reblasting to the specified surface prep.

From richard d souza of stoncor middle east llc on April 16, 2012:
     It is not about how long but the highest criteria is the steel temperature shall always be at least 3 degrees C higher than calculated dew point temperature. This margin of saftey is sufficient for all type of coatings. The common scenario is that the contractor blasts all day long, then experiences problems with the compressor or other piece of equipment, and lets the newly blasted steel sit a long time before coating. But the standard requires that the surface to painted must meet the cleanliness criteria set by the client or consultant which supersedes every other judgment. In Jordan, for example, oxidation or orange rust may not occur for serveral hours or days, but in UAE, you can probably expect to see rust breakthrough in few hours depending on the time of the day or night. It is almost impossible to state the effect of time,   temperature and humidity  on the blasted surface. This  must be the sole responsibility of the inspector, who conducts on-site checks of the following: -Place of work -Air temp min/max -Relative humidity -Dew point temperature -Steel temperature -Necessary ventilation -Type of weather-sun, wind etc. -Wind directions. And this must be done a minimum of thrice per shift. The inspector should have the sole right to determine the time without deviating from the specification.

Please sign in to submit your answer this question    

Tagged categories: Abrasive blasting; Humidity and moisture; Substrates; Surface preparation


Current PSF Question | Submit a PSF Question | Full PSF Archive

Axxiom Manufacturing
Schmidt Improves Conversion Kits

Schmidt's conversion kits turn out-of-date blast pots into high quality, efficient blasters. Quick, easy to install with step by step instructions.
Call 1-800-231-2085


CHLOR*RID International Inc.
Hold*Blast

*Provides outstanding
  performance
*Easy to use and only pennies
  per square foot
*Works with poor quality
  water
*Use for mist blasting, vapor
  blasting, wet blasting and
  UHP WJ
*Leaves no residue and
  provides excellent adhesion.
  www.chlor-rid.com


Atlantic Design, Inc.
BUILDING INNOVATION, NOT IMITATION

The smallest version of our Blast Vacuum Recyclers, this ADI 2300CFM 2-Pot is a cleverly designed power package for those smaller jobs. 866.Call.ADI


Absolute Equipment/Grand Rental Station
TIER 4 EQUIPMENT

We have Tier 4 Equipment including Air Compressors & Generators for Sale & Rent! Your job may now require Tier-4. www.absoluteequip.com or Call 412-931-6655.


able equipment rental
RENTALS | SALES | SERVICE | PARTS

Construction equipment, plus compressors up to 1,800 cfm of air power & a fleet of service vehicles providing repairs to customer owned fleets. 866-468-2666.
www.ableequipment.com


Clemco Industries Corp.
Powerful Protection in a Small Package

Mounts inside blast helmet, alerts operator to dangerous breathing-air condition by audible, visual, and vibratory alarms. Easily calibrated, battery operated.


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


Novatek Corporation
Novatek Corporation, Dustless Coatings Removal

Strip, clean and profile all dust free! Comply with new lead standards. Contact today: (866) 563-7800


Monti Tools, Inc.
BRISTLE BLASTER® - THE ORIGINAL ONE

Surface cleanliness of SSPC-10 | Anchor profile
up to 4.7 mils | Removes corrosion & coatings |
ATEX approved for zone 1
| www.monti.com | 832-623-7970


SAFE Systems, Inc.
Portable Dust Collectors for Tough Environments

Trailer and skid-mounted models in numerous sizes, powered by electric and/or diesel. Sloped roofs, multiple dust inlets, high static, dampered fans. Lockable power & drive compartments.

 
 
 
Technology Publishing

The Technology Publishing Network

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

 
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 2000-2016, 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