Presentation on theme: "Determination of Dry Coating Effectiveness Against Water impregnation. An examination of various testing methods. William J. (Bill) Fronzaglia P.E. Director."— Presentation transcript:
Determination of Dry Coating Effectiveness Against Water impregnation. An examination of various testing methods. William J. (Bill) Fronzaglia P.E. Director of Engineering New England Ropes, Inc. 848 Airport Road Fall River, MA 02720 USA Phone: 508-678-8200 / 800-333-6679 Fax: 508-679-2363 / 800-647-6731 www.neropes.com
UIAA Journal 2/2001 Pg. 25 Available at WWW.UIAA.CH
Definition dry (dri) adj. Etymology: Middle English, from Old English dryge; akin to Old High German truckan dry, Old English drEahnian to drain Date: before 12th century 1 a : free or relatively free from a liquid and especially water b : not being in or under water c : lacking precipitation or humidity
Fact: By Definition: Reduced water impregnation will reduce weight gain. Assumption: Keeping water out will keep performance up Proper care and handling to reduce unnecessary water exposure is best 1 st choice.
Behavior of Nylon when Wet. Weight Gain Decrease of tensile strength by 10% - 15% Decreased resistance to Yarn on Yarn Abrasion. Reduced Elongation Increased Impact force Decreases number of drops sustained. Increased diameter Increased risk!
Yarn Finish/Coating Technology Spin Finishes Marine Overlay Finishes Wax Emulsions Mineral Oil based products Silicone Multi part polymer coatings Proprietary coatings
Dying process removes beneficial finishes Benefits of coating Improved Hydrophobic properties Improved Yarn on Yarn Abrasion Resistance Improved Yarn on Metal Abrasion Resistance Decreased Internal Yarn on Yarn Friction Reduction of dirt impregnation Increased Life?
Alternate Test Methods Water Droplet Test Flotation / Buoyancy Test. Shower Test – Mammut German Military Standard –Test TL 4020-0015 (BWB) Dynamic Ropes. Method A Method B (72 Hour Immersion) U.S. Fed. Test Method Std. No. 191A –Method 4500 –Method 6011 (24 Hour Immersion) 1, 2, 4, 24, 48, 72 Hour Immersion
Conclusions All dry coatings are not equal. Ropes with better performance perform better in all tests. Some ropes have a barrier which allows them to float, this barrier is very fragile. These tests only address weight of water absorbed, not performance when wet.
Conclusions Best Test Method –Standard length samples. –Hold sample submerged to prevent surface tension effect. –1 hour duration, Longer is not necessary. –Drain on rack for 3 min.
Further Study Required Decrease in performance of nylon ropes vs. % of moisture gained. Real world exposure. Which method is most realistic?