Technical Editor Ralph Naranjo’s market survey of mechanical rigging terminals in the June 2015 issue of Practical Sailor demonstrated just how long these terminals can last if they are installed correctly. That report came close on the heels of the late great rigger Brion Toss’s photo essay on what can go wrong if they are not assembled correctly, or assembled without any sealant. My previous blog post “Tricks and Tips to Forming Do-it-Yourself Rigging Terminals” rigging terminals highlights a number of important details, including the use of caulk, that Naranjo delved into in the 2015 report.
What is interesting is that some of the makers of mechanical terminals do not make it entirely clear on where they stand with regards to sealants. Some recommend using a caulk or sealant, but don’t specify the type-and as we know from our previous sealant tests, there are many.
One company, Hi-Mod, advises that installers use Loctite 262 or a similar thread-locking compound to prevent galling. Hi-Mod makes no mention of using a sealant in the installation guide. StaLok, on the other hand, advises that the terminals be sealed, and Sailing Services, a Miami Rigging company who has consulted PS in the past, suggests Life Calk. The Sailing Services website offers a detailed description of the StaLok installation procedure.
Naranjo, who used both a polyurethane sealant and Loctite on his sloop Wind Shadow, recently had an opportunity to examine the results after years of marine exposure. The photo below shows a Norseman fittings that Naranjo installed nearly a decade ago. Although there is some rust staining at the wire ends, it is minimal. Now compare that photo to the one of corroded fittings that Toss photographed for his report.
photo by Ralph Naranjo
If you need more details on how and where you apply the sealant and the thread-lock during installation, Naranjo describes the process in a step-by-step description of installing a mechanical terminal for wire rope accompanying his market survey in the May issue.
Currently, we don’t have much data on how well a sealant-free Hi-Mod installation will hold up in the marine environment (some riggers add sealant anyway). Why advise against a sealant? One concern we’ve heard is that a strong adhesive sealant will make it hard to disassemble for inspection. We have not found that to be case—except with 3M 5200 (which interestingly does not adhere well to stainless steel).
There is no question that a thread-treatment such as Loctite 262, Loctite 242 is necessary. This is good protection against galling, a common affliction for any stainless fitting that is under load. As far as the use of a sealant goes: in our view, a sealant (used correctly) offers good insurance against water intrusion in a saltwater environment. We would recommend it regardless of brand of terminal you use.
Many riggers prefer silicone sealant, but aboard Wind Shadow, polyurethane sealant worked well. Sailing Services recommends Life Calk. We no longer recommended the polyurethane sealant 3M 4000 UV, because it failed catastrophically in our test. We do not recommend 3M 5200.
very interesting to me — and the comment on the rust on the ends of the wire views looking into the open terminal — we cut small lengths of new wire and test in a salt water bath to check for any rust –and our samples stay clean and bright for months except for the ends — and surface rust is from the wire cutter — C-12 Tool steel blades – leave behind micro particles that rust– not the wire rusting !
And the Life Caulk — 50 years of putting to together STA-LOK – we know it works –
Brooks – Sailing Services, Inc —
Great information I have a question though. My rigging is 20 years old and is in good shape according to a rigger who recently tune it. Would it still be prudent to seal the rigging or has the overall damage already occurred?
Sta-Lok does NOT recommend sealing their fittings. A representative mentioned that you CAN use sealant that consists of a neutral compound (otherwise you may trap acid within the fitting), but that it is not necessary.
One other important note. If you do decide to use thread locker, you will need to clean out the TefGel that is coating the threads from the factory at Sta-Lok in order to get proper adhesion. Don’t forget to prime the stainless with the proper product for your thread locker agent or there will not be proper adhesion thereby making the thread locker less effective.
In 1992, I replaced rigging with US made 316 SS wire and Sta-Lock terminals. I have been very pleased. Every year , I randomly open at least one lower to inspect. Haven’t hit a bad one yet. Any uppers that appear Q, have likewise had no problems.
Some were filled with Life Calk, most not. Originally sealed threads with “blue Loctite” some different brands after inspection, again, no problems.
One thing I have done, is shoot WD-40 into lowers appx monthly. It may be beneficial by driving out stagnant water and leave a slight anti-corrosive coating. I think it may be better than even filling the fitting with a caulk, since water will inevitably find its way thru the wire strands in spite of being filled. The caulk could then trap water without oxy against the wire, and at least theoretically “activate” the SS to corrosion. There has been an occasional use of penetrant, or T9, when no WD40 aboard.