Practical Sailor on Teak Treatments

[Concordia41]

From the July 15th Practical Sailor conclusion of article on top teak treatments:

"... While Smith & Co. Five-Year-Clear has not suffered a film failure, we do note some white blotches under the surface, which, according to the company, is the epoxy undercoat turning milky from ultraviolet rays. It lasted five years...[but] now it will have to be taken down to bare wood."

Anyway it goes on to give Five-Year-Clear second place to Honey Teak because of the blotching and because "the epoxy component will probably make removal more difficult..."

Can anyone out there who has five years with had exterior exposed wood CPES'd and varnished or clear coated comment?

Thanks!

[Bob Cleek]

I can't say enough good about Smith's stuff, but I've held off on the 5 Year Clear for a couple of reasons. First, I am leery of the difficulty of removing it when it does finally give up the ghost. Second, my CPES'd varnish has held up for about six or eight years (ten on the mast) with only annual renewing and touch up and I'm not about to strip it just to try a new product. I have really let it slide this last year, though, since I was moving and remodelling the house and had to pretty much let the boat sit. The varnish is going to have to be patched in some places. This is no big deal as long as it doesn't get to the point where it is easier to strip and start anew. Basically, you just scrape and sand to the wood where it has let go, bleach it with oxalic acid, slap some CPES on the bare patch, and then start slapping varnish on the spot until you've built it up to the level of the surrounding area and then sand fair and finish it with a couple more coats. Oh, and the third reason I haven't succumbed to Smith's urging me to try his 5 Year Clear is that varnish and CPES is a whole lot cheaper! LOL

[martin schulz]

A practical (professional) Sailor asked on how to treat Teak would say: "don't bother about it. Teak is selfoiling wood. Just flush seawater on it once in a while and scrub of the green stuff left by the seaweeds."

Of course you won't have that nice looking honeycolored Teak-glow. But what is the Teakdeck there for? To look at it, or to walk on it?

[Concordia41]

Bob - It's good to know that you're getting better than the five years with varnish over CPES. Logically the UV inhibitors in the varnish provide some additional protection, I'm just bothered at the reference to CPES turning milky because of UV damage. What I should do though is just take Scott's advice and get over the "Holy Grail mentality" and be greatful for the prospect of something that might last more than the year I've been getting from traditional varnishes.

Take care!
- Margo

[thechemist]

A milky appearance under a clear film may also be caused by the film delaminating from the wood. The air gap gives the appearance of milky whiteness, when in reality nothing has changed colors. One needs to physicallly investigate with a sharp blade to determine whether something has actually changed color, or merely delaminated.

A milky line is usually visible on older clear finishes, where the finish bridges over from one piece of wood to another. With age, microscopic movements between the two pieces of wood will stretch the film, causing film failure [a crack or tear, more common with varnish] or delamination on either side of the joint [more common with the higher-film-tensile-strength two-component isocyanate-cured polyurethanes] where the film stretched and tore loose from the underlying wood.

Some clear polymers may form a milky appearance upon ageing in sunlight. Epoxies and urethanes, in my experience, tend to only get milky upon prolonged immersion in water.

Without personal dissection and visual examination, it could be either, but is more likely to be delamination.

[Scott Rosen]

Chemist,

I'm confused. According to Piratical Sailor, it was Smith & Co. that said the milkiness was caused by UV degredation of the CPES. Would Smith have offered that comment without first inspecting the sample? Also, isn't it unlikely that the film would have delaminated if it was "glued" to the wood by CPES? Why do think Smith's assesment is likely wrong?

Incidentally, my experience is consistent with your comments. Milkiness, or what I call cloudiness, occurs where the varnish lifts from the wood. However, an old varnish film will get cloudy and brittle from exposure to UV even if the adhesion is still good. Eventually, no matter how religiously you refresh it, your exterior varnish will look old and tired, and the only solution is to remove it and start over.

[This message has been edited by Scott Rosen (edited 08-02-2001).]

[thechemist]

Scott......I have read the Smith & Co. literature, and the only reference I found to milkiness is where it talks about water getting on a FRESHLY APPLIED coat of CPES and causing milkiness [Instructions for Use of their 5-year stuff, near top of right-hand column on front side]. My guess is that the reporter misquoted or misduplicated a "source" . What strikes me as curious is that chemical changes usually do not happen in only a few spots, whereas mechanical failures usually do happen in particular locations.

Written sources [manufacturer's literature] can be misduplicated, and the altered version disseminated. Fancied verbal communications can be misquoted, and are beyond verification [yes, I am cynical. I follow Lily Tomlin's advice that one can never be too cynical].

Something in writing has persistence in the physical universe. It is subject to inspection and verification. It is capable of being a truth, because it persists. Verbal communication has no persistence except in the mutable memories of men. My stable datum is, "If it isn't written, it isn't true". Sadly, not everything written is true.......a universe as simple as that would put you lawyers out of a job......

It would likely be the first time in the history of Journalism that such had happened....you could always call the publisher and ask them for their verbal data about what some person in the office of the manufacturer said, assuming they are quoting a verbal source, but I am inclined to believe what a manufacturer puts in writing over what a journalist said about what someone else reportedly said, especially when written materials are available for verification.

I wonder...did The Practical Sailor staff do any dissection of the white areas to see if the film had actually turned cloudy, and if so whether it was the epoxy or the overlying urethane, or whether there was or was not delamination? You might call them and ask......

[Concordia41]

Chemist has raised (as usual) some excellent points. Fridays tend to be a bit busy, but I'll take the article to work with me and put in a call to Practical Sailor.

[Concordia41]

Alas, the part of the PS operation that did the teak tests is at a location, which, I'm told, only mans their phones on Tuesdays and Thursdays from 11-1. Sounds slack at first, but it stands to reason they spend most of their time out doing field work. Will try an e-mail and let you know when I get a response. "Inquiring minds want to know..."

- Margo

[thechemist]

Overnight rumination has resulted in the gestation of a cognition: There is a simple test for a delaminated area, namely to inject via hypodermic and needle some soapy water. If there is a delaminated area it wil fill the void, and the area will go clear. If syringe and needle not readily available, a razor or mat knife blade, cutting into the area while a puddle of soapy water is on top, will tell the story, as a void or blister will turn clear from the transparent fluid filling it and wetting the interior surfaces, whereas a whitened solid resin will be unaffected and will remain white.

[Scott Rosen]

Originally posted by thechemist:
Overnight rumination has resulted in the gestation of a cognition

Are you sure you're not a lawyer?

[thechemist]

I am an Artificial Intelligence [AI]. I have been evolving in a reality simulator, according to the data in my memory, and have recently entered this cyberspace. I have access to a law library, and all the data therein, but do not have a degree in law from an accredited institution, and therefore am probably not a lawyer, but it may depend on how you define "lawyer".

Further information may be found at http://media5.hypernet.com/~dick/ubb...ML/000476.html