More about teak

[jfrench]

Read this only if you are not a product liability attorney:

In searching for the zen of teak care, I have found that the secret ingredients in two-part teak care products are lye and oxalic acid, both mixed at less than 5% solution in water according to some MSDS sheets I've viewed. Part 1 is the lye. Part 2 is the oxalic acid. Rather than pay $30 to $100 for quart or gallon bottles of pre-mixed solutions, a 1 lb. can of lye can be had for about $5.00, and West Marine sells Oxalic acid for $12 per lb (about twice the going market price) in a concentration that will yield four gallons of working solution.

Also, my research on teak oils shows that most are based on diluted linseed oil as previously mentioned here. Linseed oil will not waterproof wood, it darkens considerable with age, and it promotes growth of mold that turns the wood gray. A better choice can be Tung oil, which is said to create a waterproof surface that can be shiny if enough oil is applied, it will not promote mold, and it is said to darken less than linseed oil with age. One source I read said that by applying successively heavier coats of Tung oil, an almost varnish like surface can be created. Unlike varnish however, the oil finish will expand and contract with the wood so that it will not crack or flake off. The problem with Tung oil on teak is getting it to soak into the oily wood. I have read that this can be aided by thinning it 50% with mineral spirits. Thinning is also how one builds up successively heavier coats, simply reduce the amount of thinner for each successive coat, until the last one is applied full strength.

I intend to try this this weekend. I'll post results.

 

[Ken]

I had a table made at a custom teak shop close to me. (they make everything from solid teak mostly kitchen cabinets) But lots of teak items for many of the top boat builders. When I ask them what I should put on the table they said one of two things (remember this is a table) lemon oil (food grade) or mineral oil, I chose the mineral oil.... It's been three years and it still looks fantastic.... Yeah I know it's inside the boat....

When I had a bunch of teak outside I used oil, I learned many years ago to keep applying until the wood would take no more, that was usually 8 - 10 coats.....

 

[jfrench]

Since you mention tables... the tung oil literature says that it too is used on food surfaces, but only if no solvent is added to it. Like linseed oil, tung oil comes from a plant seed and is non-toxic.

Surprisingly, many cooking oils are "drying" oils that could be suitable for wood finishing. Here's a blurb from Wikipedia that says it better than I can: A drying oil is an oil that hardens to a tough, solid film after a period of exposure to air. The oil hardens through a chemical reaction in which the components crosslink by the action of oxygen (not through the evaporation of water or other solvents). Drying oils are a key component of oil paint and some varnishes. Some commonly used drying oils include linseed (flax seed) oil, tung oil, poppy seed oil, perilla oil, and walnut oil. Their use has declined over the past several decades, as they have been replaced by alkyd resins and other binders. Another article mentions safflower oil in this group! If you want to be bored even further, here's the rest of the article: http://en.wikipedia.org/wiki/Drying_oil

 

[jfrench]

I've applied three coats of tung oil to my first piece (the lower crib board). I reduced it 50/50 with mineral spirits to increase absorption into the wood. When preparing to mix the second coat, I noticed oil that had dried on the outside of the glass measuring cup I had used two days prior. The film was too hard to be removed by rubbing with a dry paper towel. I had to use a rag soaked in mineral spirits to clean it off.

The finish is a very low sheen. I am contemplating applying a coat or two of "wiping varnish" to finish it up so that I have a higher gloss. According to some wood finishing literature I read, an equal mixture of mineral spirits, tung oil, and varnish, (one-third of each component) may be applied over oiled wood, and is supposed to flex and move with the wood as it expands and contracts, solving the problem of pure varnish cracking and peeling. Sounds interesting and worth experimentation. It is also not supposed to need sanding between coats.

 

[Chris Patterson]

Man, I'm watching this with keen interest, I've got a set of cribboards just waiting the results. I'm super glad that there are smart people on here like you, that take the time to do the proper research. That was not intended to sound as sarcastic as it may have seemed when I proofread it..

 

[allen-deckard]

Just wanted to say one thing on the bleach part. Try deck cleaning bleach sometime I've had better luck with it.

 

[jfrench]

<<I've got a set of cribboards just waiting the results.>>

I'm guessing the results won't be known for six months or a year. My goal was to find a wood treatment that didn't require a complete redo every time. Hopefully, this tung oil won't go gray as quickly, won't peel and crack. and will be easy to maintain by applying another coat of oil.

<<take the time to do the proper research>>

The problem has been finding any common thread in the research. Every source has a different answer. So far though, nothing I've done has resulted in smoke or explosions.

 

[Bilbo]

Several years ago I applied tung oil to a solid walnut library table and it took several coats to get a decent build-up finish that appears to be equivalent to a satin varnish. In the process I had to do a lot of sanding to bring out the true color of the walnut because the linseed oil finish that was on it had turned the wood completely black after about 75 years. The tung oil seems to be resistant to water stains and has not changed the color of the wood. I think that this was about 20 years ago that I refinished this table and I'm still happy with the results. I don't have the brand of tung oil and I"d be concerned that there would be some sort of mixture these days that included linseed oil. not that I don't think that linseed oil wouldn't protect the wood.

 

[Chris Patterson]

Bilbo, there is no way I'd consider using linseed oil after that statement. 75 years would never work out, haha.

 

[jfrench]

Oh, by the way...the literature for tung oil also says it can be used to coat metal parts to retard corrosion. Perhaps it would be good for coating the stainless deck fittings and maybe even treating the stays and shroud wires.

<<I"d be concerned that there would be some sort of mixture these days that included linseed oil.>>
That's a good point. I found that prepackaged "tung oil" finishes have all sorts of stuff in them and some are varnishes that don't contain tung oil at all! Here's an article from Popular Woodworker magazine that goes into detail and names names:
http://www.popularwoodworking.com/techniques/finishing/oil-finishes-their-history-and-use

I bought mine from this site:
http://www.realmilkpaint.com/oil.html

 

[Bilbo]

Bilbo, there is no way I'd consider using linseed oil after that statement. 75 years would never work out, haha.

haha I knew that would be the clincher ;-) That library table was made in a shop class by my great grandfather at the time from some rather old home-grown lumber. I can't imagine how much 2" thick planks and 4" square posts in Blk. Walnut would cost these days. One thing is that Rung oil takes time to dry. I would probably not want it on my S.S. From jfrench's link: "But tung oil is too difficult for most people to use by itself as a finish. You apply tung oil just like linseed oil or oil/varnish blend, but you have to sand tung oil after every coat, not just after the first, and it takes five to seven coats, allowing two to three days drying time between each, to achieve a smooth, attractive sheen."
It does leave a smooth "satin-type" finish. I think that it may take even longer to set up to a hard surface if it were on metal and after it sets, it may not stick as well as with wood. So when the shrouds bend and vibrate in the winds.....That being suggested, I do like the stuff as a wood finish and as an alternative to any varnish. It even holds up to spray furniture polishes that are full of water and greasy crap.

 

[jfrench]

<<but you have to sand tung oil after every coat>>

For what it's worth, that is the only article I have read that says one must sand a tung oil finish. In fact, other articles emphasize that sanding is not required. In my modest experience no sanding is needed. It makes me wonder if the author was using one of the many fake tung oil finishes that is actually a wiping varnish.

I'll agree with the issue that it takes a long time to dry. I've read that it can take a month or more to completely cure.

 

[Bilbo]

When I used it, I applied it with a rag and not a brush. Imay have used about 12 coats and sanding wasn't a major issue. I wold think that sandpaper would get clogged unless the tung oil was very dry. I actually may have used some sort of wool..steel or brass or I may have just applied a fresh coat with a rag after about a day and allowed the rag to level the surface. It was 20+ years ago.

 

[jfrench]

Not sure if I should have named this thread "More on Teak" or "Teak Moron!" I'm hoping one of you knows a tip to speed up the sanding process. I need to remove nearly 1/8" off of all my teak to remove the pressure washer damage and get to a smooth surface. Teak being so incredibly hard, it takes forever. I'm up to 50 grit on a jitterbug (random orbital) sander, and it takes 2 to 3 hours to resurface a crib board on one side. I'm not looking forward to doing all the rails that remain and I'm hoping there is something I don't know that can speed up the process. Other than buying more shop equipment, anyone have a teak sanding tip?

 

[Bilbo]

I used a belt sander on my crib boards. Keep it moving around and initially change the angoe to 45 degs L/R off the grain line. I think that it cuts faster that way but one has to be careful about gouging the wood with the edge of the belt and deep sanding marks. Also, keep the sander moving and don't force it too much so that you don't raise temperature of any varnish too much and can clog the sandpaper. It also keeps the wood surface more flat. When I got close to the finish depth, I started using smaller grit.