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  #1  
Old 09-18-2012
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Liquid Penetrant Inspection?

Is Liquid Penetrant Inspection a common diagnostic tool used for rigging inspections?

Tundra Down is enjoying a rejuvenation worthy of its pedigree. I don't know the age of the standing rigging but I am starting to budget for replacements. I do inspect every inch by touch and visually examine each fitting looking for signs of age. It all looks solid but could easily be quite old. This boat spent its mid life on the hard.

The vinyl covered lifelines have been bleeding rust in several places. I noticed a split starting in one of the bow terminals and put their replacement on this years to do list. I can imagine these are original!

Sunday we had 15+ ssw and enjoyed a lively sail. Returning to our mooring as I "carefully" leaned against the stbd lifeline, with a firm grip on the bow rail, to reach the mooring with the boat hook, IT PARTED!!! I heard the "pop" and felt it relax. I was wearing my Mustang pfd and found myself still holding tight to the bow rail with my left hand, the boat hook with my right, pleasantly surprised that the water in Seal Harbor was actually swimming temperature. Ha! I switched hands and was facing the stern holding onto the toe rail. I was only wet half way up my chest. The life vest did not get wet enough to deploy. My shoulders were dry and I was headed for the rope ladder we hang over the transom. My wife had managed to grab the dinghy and it was tied to the mooring. When I made it to the stern I was sharing the water with mooring lines, an Avon and my rope ladder. I got a mooring loop onto the stern cleat and climbed up the ladder. No harm no foul. My wife was a little shaken watching me go over the bow. I was fine. I have a lot of time in the water over the years. BUT!

It was a most fortunate event. If something had happened while we were at hull speed in a sea of lobster pots tacking against the strong running tide in Eastern Way, the consequences of that failure would have been a bit more inconvenient. I know the water would have been colder out there. Ha! Sobering thoughts for sure.

I had seen what I thought was a crack in the fitting that failed. I noted it and was thinking about it. It was one of those, "Should I put in a reef?", moments that I didn't heed! Lucky me! I didn't even drop the boat hook.

There is a temporary dacron replacement that will get me through the rest of the season. I will be sailing with new lifelines next year.

That brings me to Liquid Penetrant Inspection. I am interested in having a clear "picture" of the condition of my standing rigging and Liquid Penetrant Inspection looks like a worthy diagnostic step. Does anyone have any experience with this process? I would like to avoid any more "surprises"!

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Last edited by downeast450; 09-18-2012 at 08:02 AM.
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Old 09-18-2012
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Re: Liquid Penetrant Inspection?

I tried dye penetrant without much success. Finally, I used very fine sand paper to clean all brown stains from the stainless fittings and inspected with a 10X loup. WOW, cracks in my 20 yr old rigging. Generally, the cracks had been hidden by a spot of brown rust and only visible with the magnification.
I saved one of the cracked ones and eventually will get SEM pictures of them.
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Old 09-18-2012
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Re: Liquid Penetrant Inspection?

I think you answered your own question, but, I will reiterate:
Should I reef?
Should I replace my lifelines?
Should I replace my standing rigging?

Winter is coming, you are in Maine, seems like a good time to get things done.
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Old 09-18-2012
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Re: Liquid Penetrant Inspection?

Rob,

I will replace everything, if close inspection reveals problems. I just cleaned and inspected the lifeline's swedged end that didn't fail. I could see only swedge marks under magnification. The end that failed is split on both sides and the cable pulled out. The life lines will get replaced for sure.

If the standing rigging's fittings look sound I will keep a close eye. Then there are the chain plates? Mine look fine but I will take a magnified peek there, too.

Down
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Re: Liquid Penetrant Inspection?

I have made a career of Non Destructive Testing (40 years and counting). The key to dye penetrant is that the part to be inspected must be clean. This is usually accomplished by solvent cleaning. Any contaminants that can prevent penetrant from entering a crack must be removed. Dwell time is also important as the penetrant needs time to find it's way into a crack. Normally 5 to 10 minutes is enough unless the temperature is pretty cold. When removing the excess penetrant be careful not to over clean and remove penetrant that might have entered a crack. Arter applying the developer allow a few minutes for penetrant to "bleed out". If there is a crack the penetrant will clearly show.
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Old 09-18-2012
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Re: Liquid Penetrant Inspection?

Thanks Gramps,

Is there one you would recommend?

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Re: Liquid Penetrant Inspection?

I have used both Sherwin Inc. and Magnaflux brands. Both are industry standards. Unless you have a Black light and dark area use the visible. Both are available in solvent removable and water washable. My mast is on a tabernacle so I lower mine once a year and PT all standing rigging fittings. 1966 Bristol 27.
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Old 09-18-2012
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Re: Liquid Penetrant Inspection?

Quote:
Originally Posted by downeast450 View Post

That brings me to Liquid Penetrant Inspection. I am interested in having a clear "picture" of the condition of my standing rigging and Liquid Penetrant Inspection looks like a worthy diagnostic step. Does anyone have any experience with this process? I would like to avoid any more "surprises"!

Down
Dye penetrant (Magnaflux™, etc.) inspection is a learned art. Its used on SOLID componentry that are regularly flat/smooth surfaced ... rigging swages and terminals and T-bolts fit that category (but not the 'roots' of their threads).
The component is cleaned, the dye is applied and soaks into microcracks, etc., the surface dye is dry-wiped clean and a 'developer' is applied. If there is remaining dye, as would be trapped inside cracks or porosity, etc., it will 'wick' into the 'developer' as a 'pink/red' line of 'dot'. Zones of red lines or red dots indicate the suspicion of fatigue failure ... and then either repeat dye testing or further testing by magnetic methods should be considered to raise the index of suspicion of increasing failure potential due to fatigue cracking, etc. A pocket microscope should be used BEFORE you use dye penetrant ... to save the 'mess' of dye penetrant inspection.

MOST IMPORTANT CONSIDERATION WHEN USING DYE PENETRANT ON BOATS ..... Gel Coat is naturally porous, the dye is RED. If you get any dye into the porous gelcoat it will remain there forever, and to forevermore bleed 'pink'.
Dont ever use dye penetrant ON a boat; remove the component and do this OFF the boat.
;-)
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Old 09-18-2012
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Re: Liquid Penetrant Inspection?

Quote:
Originally Posted by downeast450 View Post

That brings me to Liquid Penetrant Inspection. I am interested in having a clear "picture" of the condition of my standing rigging and Liquid Penetrant Inspection looks like a worthy diagnostic step. Does anyone have any experience with this process? I would like to avoid any more "surprises"!

Down
Dye penetrant (Magnaflux™, etc.) inspection is a learned art. Its used on SOLID componentry that are regularly flat/smooth surfaced ... rigging swages and terminals and T-bolts fit that category (but not the 'roots' of their threads).
The component is cleaned, the dye is applied and soaks into microcracks, etc., the surface dye is dry-wiped clean and a 'developer' is applied. If there is remaining dye, as would be trapped inside cracks or porosity, etc., it will 'wick' into the 'developer' as a 'pink/red' line or 'dots'. Zones of red lines or red dots indicate the increased suspicion of fatigue failure ... and then either repeat dye testing or further testing by magnetic methods should be considered to raise the index of suspicion of increasing failure potential due to fatigue cracking, etc. A pocket microscope should be used BEFORE you use dye penetrant ... to save the 'mess' of dye penetrant inspection.

MOST IMPORTANT CONSIDERATION WHEN USING DYE PENETRANT ON BOATS ..... Gel Coat is naturally porous, the dye is RED. If you get any dye into the porous gelcoat it will remain there forever, and to forevermore bleed 'pink'.
Dont ever use dye penetrant ON a boat; remove the component and do this OFF the boat.
;-)
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Old 09-18-2012
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Re: Liquid Penetrant Inspection?

Thanks Rich,

My next effort will be to clean and inspect with magnification. Nothing is getting replaced until we are on the hard but I am curious and will take a kit out Thursday to do some checking.
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