Galvanized Turnbuckles and Paint

[Jak Mang]

I'm reconditioning some galvanized turnbuckles. These have been painted and have lasted 30 years in pretty good condition. The rusty areas are around the point of loading on the eyes and the threads where the paint has built up/chipped at the point of adjustment. Paint sickness seems to be a good place to collect water. The load points are less of an issue, but should I paint those threads or just keep them greased? Any other thoughts on coatings would be appreciated.

Thanks,
-jak

[Clyde Jenkins]

If the turnbuckles are showing rust it means that the galvanizing, the zinc coating, has gone away and now the steel is exposed. Galvanizing is, like the zincs on the prop shaft, a sacrificial anode. It is meant to corrode before the base metal.

I see several alternatives for you.

1. Galvanized turnbuckles are a lot cheaper than their stainless steel counterparts. You could replace the turnbuckles with new ones.

2. I like the idea of reusing serviceable parts. You could get the old parts sandblasted or use a chemical paint stripper to remove the old paint. Then get them regalvanized. Beware of trapping sand in the threads. Paint over the galvanizing if desired.

3. In the spectrum of corrosion resistant coatings for steel galvanizing the the king. A somewhat distant second is powder coating. Painting with other paints is usually last.

Painting the threads is a bad idea. If you have extensive rust in the threaded areas you may have lost enough metal to weaken the threaded joint. I wouldn't reuse the parts in this case. If the threads are in good condition, painting will reduce the necessary clearance to the male threaded parts. This could lead to galling or an interference fit and possible jamming of the threads.

New galvanized turnbuckles may have the threads galvanized. I don't know. But if they are the manufacturer has allowed clearance for the mating threads. If you regalvanize you may have to run a tap through the holes to clean up the threads. If you powdercoat or paint make sure the threads are masked. When you're ready to assemble lubricate the threads with Lanocote or Tef-gel or something suitable.

While I like re-using old parts, if the strength of the part is compromised it makes sense to start over. If there is any cracking or if the threads are deteriorated recycle the old parts as scrap steel and buy new.

Good luck,
Clyde

[Stumble]

Jak,

I read your post, and to me what I heard was 30 year old parts... no longer in good condition... how do I rectify them.

For me at 30 years old unless a part is unusually expensive, which would justify perhaps x-ray analysis of other extrodinary tests to ensure they are still good, I would just replace them and write the manufacturer to compliment them on makeing a product that stood the test of time. Particularly in light of the fact that it is normally recommended that standing rigging be replaced every 10-15 years or so, your parts have gotten an extrodinary life span.


If I had to reuse them... there are a number of companies that can sand blast and re-galvanize parts, they normally charge by the pound with some minimum charge of say $100. The problem with this in your application however is that you can't be sure about the fatigue limits of the parts you are trying to repair.

[Brian Duff]

ohh, you could anneal the pieces before galvanizing!

whoa!

[Stumble]

LOL just get a new part. Annealing then anodizing a 30 year old part......... I would cry

[Jak Mang]

I had already sand blasted and re-galvanized these. I will skip the paint on the threads and lubricate them well.

I believe that the parts are in generally good condition and I am replacing some adjacent shackles that had more wear. The rust was only surface stuff. My understanding is that high quality galvanized fittings that are properly sized and maintained will last a very long time. While cheaper than bronze and stainless, US-made Crosby galvanized is quite a bit more expensive than the Home Depot/imported stuff.

[Stumble]

Jak,

All kidding aside if you are seeing rusting and pitting in a turn buckle particularly at the thread, then it is time to replace them. While it is true that galvanized metals can last decades if done properly the parts you are talking about have already started to fail. Assuming that you are not talking about large commercial turnbuckles (for example the ones holding up the denver airport roof) they are just not expensive enough to justify risking the thousands or tens of thousands of dollars of equipment relying on them.

Compare the price of a new stainless steel turnbuckle at westmarine (about $40) to the cost of a mast (depends on size but for a 30' boat including shipping about $10,000) Not including the sails (say abother $5,000) and the likelyhood of additional hull damage or personel being injured. For me this amounts to risking the entire boat, the people on board, and pretty much all the equipment you have with you to save a few bucks. For me it just isn't worth it.

the part you were talking about repairing you said had corrosion evident at the threads. This is particularly concerning since it is very hard to propery protect threads in a screw/bolt assembly. The problem is that any anti-corrosion coating is limited in thickness by the necessity of being able to fit into the properly sized matching part. If the thread is now too thick then it won't fit the bolt. Forcing you to use non-matching parts which accellerates the likelyhood of failure due to cyclical stresses due to movement between the parts.

Finally I will warn you that should someone be injured as a result of this part failing the potential legal liability is much greater reusing refurbished parts than replacing them with new. Depending on the juridiction you could reasonably be looking at between 3 and 5 times the actual damage being awarded in punative damages.


All in all the risks of the actions you are undertaking seem to be to be unreasonably high particularly when compared to the cost of replacement. Though you are of course entitled to your own opinion.

Stumble
100 ton Captains License
Attorney specializing in Maritime/Admiralty law, licensed in La, and Fed Court
30 years of boating experience


Note: This post is not intended as legal advice and should not be contrued as such. No attorney/client relationship has been formed by way of this post. The poster recommends speaking to an attorney licensed in your jurisdiction for legal opinions.