This is a short monograph on the appearance of a rusty surface cleaned with water blasting (hydroblasting) (waterjetting).
Tag Archives: surface preparation
Comparison of Wet Abrasive Blast (WAB) and Dry Abrasive Blast Cleaning
There are many methods of wet abrasive blast cleaning (WAB) in surface preparation to remove coatings.
Since the 1980’s, Carolina Equipment and Supply Co. (CESCO) has been supplying WAB equipment along with recycling methods.
Recently CESCO sent me two youtubes to directly compare traditional dry abrasive blast cleaning and Wet Abrasive Blast Cleaning using their AquaMiser (TM) equipment. I would like to share the youtubes with you.
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Dry Blast (Traditional Abrasive Blast Cleaning) Surface Preparation
Parameters: 375 cfm compressor at 100 psi using a # 8 venturi nozzle
The panel was 54” x 28” (137 cm x 71 cm) (10.5 sq. feet) and was coated with an epoxy primer and poly urethane topcoat.
Abrasive: Dupont Starblast 101 using 18 lbs per minute at a cost of $.22 cents per lb (total abrasive cost $23.76)
Time: 6 minutes
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Aqua Miser Wet Abrasive Blast Cleaning (Surface Preparation)
Parameters: 35,000 psi 3 gpm using the F40 Abrasive Fan Gun with a 15 degree tip
The panel was 54” x 28” (137 cm x 71 cm) (10.5 sq. feet) and was coated with an epoxy primer and poly urethane topcoat.
Abrasive: Dupont Starblast 101 using 2lbs per minute at a cost of $.22 cents per lb (total abrasive cost was $1.32)
Time: 2 minutes 43 seconds
Quality of Water for Protection of high-pressure pumps and Surface Preparation
For 30 years, I have received questions about the quality of water that should be used for removal of coatings. How much dissolved material or minerals gets left on the surface? Just recently after an hour long webinar to 200 people, the question was “What should the quality of the water be?”
Among the first comments which I received on the WJ standards documents came from Singapore: The complaint was that we didn’t advocate cleaning with brackish or filtered seawater.” Just recently in 2015, a Sherwin Williams representative talked about the methodology in Brazil where WJ was being used for primary surface preparation, and not just potable water. However, I also received call in the mid 190’s where contractors said that they could tell the difference of quality of water between municipality sources. The better the quality of water, the better the removal, and the less flash rust.
As a task group leader for NACE and SSPC, the task groups finally defined surface preparation water. Surface Preparation water is water of sufficient purity and quality that it does not prevent the surface being cleaned from achieving the WJ-1 degree of surface cleanliness or nonvisible contaminant criteria when contained in the procurement documents. SP water should not contain sediments or other impurities that are destructive to the proper functioning of the cleaning equipment.
The following is a monograph on
The Quality of Water to be used in Surface Preparation and to Protect the Pumps.
EVALUATION OF 20,000 PSI WATER JETTING FOR SURFACE PREPARATION OF STEEL PRIOR TO COATING OR RECOATING
EVALUATION OF 20,000 PSI WATER JETTING FOR SURFACE PREPARATION OF STEEL PRIOR TO COATING OR RECOATING
This is the original white paper monograph which is the basis for removal of paint and coating system by high pressure waterjet cleaning HP-WJ. Prepared by Lydia M. Frenzel; Dr. Robert De Angelis, and Dr. John B. Bates, 1983
At the time, 20,000 psi (140 mPa) was the upper limit on the cleaning equipment. Click on the link to download the pdf paper.