grey coloured teak

[icepatrol]

my teak decking is grey in colour. is this normal and healthy for the wood ?
can it be left like that and last or does it need treatment ?

 

[rob2]

Actually, that's the easiest way to keep teak in good order! Just wash it down regularly with seawater to prevent anything growing on it. Use a sponge or soft brush to avoid wearing the surface. Perfect maintenance task for a slow summer's day.

Rob

 

[ksutton]

Grey or silver teak is fine. but in reality when its wet it does look dirty, like an old park bench. A very good discussion on the forum last week, have a look at this.
http://www.ybw.com/forums/showthread.php?t=219891&highlight=teak

 

[Boat44]

I'm with rob2.

Some do use chenicals etc on their teak. For me I prefer salt water and abit of fairly liquid is dirty.

 

[PeterGibbs]

You can restore it to golden, as new condition, with lots of chemicals or elbow grease. Every time you do this advances by quite a lot the day you will have to replace the whole shebang.

Grey is the natural oxidised colour, and boldly showing it on your boat shows you have moved on to more worthwhile uses of your time, such as sailing...

PWG
PWG

 

[snooks]

You can restore it to golden, as new condition, with lots of chemicals or elbow grease. Every time you do this advances by quite a lot the day you will have to replace the whole shebang.

Grey is the natural oxidised colour, and boldly showing it on your boat shows you have moved on to more worthwhile uses of your time, such as sailing...

PWG
PWG

Sorry, grey is not its oxidised colour, it's the colour of all the stuff from the bottom of shoes and pollution out of the atmosphere which has got itself into the grain of the teak.

Teak left bare, and covered over so the elements (and feet) cant get at it will stay the lovely golden teak colour, it might fade slightly in the sun to a yellowy gold colour, but not to grey.

Check out under the sprayhood and glass windscreen of a Hallberg Rassy or Najad with bare teak (unvarnished) if you don't believe me

As for cleaning it, you just need Oxalic acid, water and no elbow grease. Dilute the power in the water as the instructions tell you. Wet the teak, pour the solution onto the teak, leave until it's as gold as you want it to be and rinse off thoroughly. This doesn't shorten the life of the teak or take a layer of wood off the surface, it bleaches the dirt from the grain IIRC

 

[whisper]

Interesting, not seen that suggestion before.
Would the oxalic acid attack the SS stanchion bases at all, or does a rapid rinse down prevent any problems like that ?

 

[30boat]

I have some leftover bits of teak that I've left outside for the last two years or so.They are now greyish in colour and nobody has walked on them.I believe this is the natural colour of teak when exposed to the elements.

 

[john_morris_uk]

I have some leftover bits of teak that I've left outside for the last two years or so. They are now greyish in colour and nobody has walked on them. I believe this is the natural colour of teak when exposed to the elements.

You don't need to walk on things outside for them to get dirty. Atmospherically borne dirt, pollution etc all gets into the surface of the wood. Perhaps there is a natural reaction with the oils of the teak? The sheltered bits of wood that snooks referred to don't get rained and showered by the dirt that the exposed bits get.

For whoever said that every time you wash the wood down with chemical cleaner, you hasten very quickly the day that you have to replace it, is talking baloney. Sanding it and scrubbing it hard with a stiff brush, pressure washing it, and abusing it hastens the day you have to replace it, but I don't believe that oxalic acid or the two part chemical process takes anything off the teak at all except the dirt.

 

[Chris_Robb]

You don't need to walk on things outside for them to get dirty. Atmospherically borne dirt, pollution etc all gets into the surface of the wood. Perhaps there is a natural reaction with the oils of the teak? The sheltered bits of wood that snooks referred to don't get rained and showered by the dirt that the exposed bits get.

For whoever said that every time you wash the wood down with chemical cleaner, you hasten very quickly the day that you have to replace it, is talking baloney. Sanding it and scrubbing it hard with a stiff brush, pressure washing it, and abusing it hastens the day you have to replace it, but I don't believe that oxalic acid or the two part chemical process takes anything off the teak at all except the dirt.

John, it would be good to prove what you say, but logic would seem to say that if you suddenly have bright looking teak again after the application of a chemical such as oxalic acid, surely that must mean that a new layer of wood fibre is exposed. The old wood cannot suddenly become new looking again. So application of oxalic acid wood appear to remove surface fibres of wood.

The decks stay wonderfully clean - and I mean clean with a once a year application of Brintons MMC+ and liberal doses of seawater - so why bother with Oxalic acid anyway!

 

[snooks]

John, it would be good to prove what you say, but logic would seem to say that if you suddenly have bright looking teak again after the application of a chemical such as oxalic acid, surely that must mean that a new layer of wood fibre is exposed. The old wood cannot suddenly become new looking again. So application of oxalic acid wood appear to remove surface fibres of wood.

IIRC the oxalic acid bleaches the dirt and grime that's trapped in the grain. For example similar in the way that peroxide bleaches the pigment from hair.

I believe this is the natural colour of teak when exposed to the elements.

If you leave most things exposed to the elements: teak, cars, boats, patios decking, sheds etc they will get dirty...this is dirt, not oxidisation

 

[snooks]

Interesting, not seen that suggestion before.
Would the oxalic acid attack the SS stanchion bases at all, or does a rapid rinse down prevent any problems like that ?

Oxalic acid can be used safely around all fittings. A mate who used to work on superyachts introduced me to it, and I don't believe they would take risks with their deck furniture...Although I did hear of the new lad cleaning the ships acrylic windows with jif!

If you think of it as a bleach rather than an acid, it sounds far less scary

Here's a link with a bit more info

 

[Blue5]

Oxalic acid can be used safely around all fittings. A mate who used to work on superyachts introduced me to it, and I don't believe they would take risks with their deck furniture...Although I did hear of the new lad cleaning the ships acrylic windows with jif!

If you think of it as a bleach rather than an acid, it sounds far less scary

Here's a link with a bit more info

So are you saying you just mix the oxalic acid, coat and then wash off as the instructions just ignoring the final paragraph about sanding the raised grain?

 

[Chris_Robb]

IIRC the oxalic acid bleaches the dirt and grime that's trapped in the grain. For example similar in the way that peroxide bleaches the pigment from hair.

That proves the point - bleach damages the structure of the hair very severly, so it will also damage the fibres of the wood.

Use on a superyacht is all about looks - that is certainly no reason to assume its safe.

I will stick my head in the sand on this one and follow what has been very successfull for me over many years.

 

[johnalison]

Each to his own, but while greying is normal for exposed teak, further discoloration can occur from grime, as mentioned above, and also "mildew" and lichen growth. I suspect that different sources of teak produce different problems, and while sea-water may be effective on some decks, it certainly wasn't on mine, or other boats from a similar source, and a chemical cure was essential.

 

[Quandary]

Colour of teak

Snooks, I am afraid you are wrong.
The silver surface colour of any weathered hardwood and most softwoods is not dirt, it is the effect of sunlight on timber. Many hardwoods are a different colour the day they are sawn to just a day later. However if you pretend it is dirt and scrub it off you are simply removing some of the surface each time, OK on your patio but not on something as expensive as a teak deck. The natural change can be slowed or prevented by covering or applying coatings but a permanent one has yet to be invented.
In my career as an architect we used timber extensively on the exterior of buildings and one of the main problems in detailing was ensuring that the exposure was similar so that the colour change could be managed, unless we painted it we knew it would finish up grey though we always referred to it as 'silver'.
If you don't believe me consult any good textbook on exterior timber maintenance or go to a sawmill and have a good look at any stack of seasoning timber.

 

[snooks]

So are you saying you just mix the oxalic acid, coat and then wash off as the instructions just ignoring the final paragraph about sanding the raised grain?

You mean from here:

"Remember that water will raise the grain of the wood. Let dry 24 hours before sanding. Sand down the raised grain or staining will be darker in the raised area"

I took the last paragraph to mean let the wood dry for 24 hours, then continue preparing the wood for staining or whatever.

It's possible, of course, that the area that was full of dirt is now free from dirt so the grain may appear to be raised. I don't know, I just know it's been used successfully round the world for years. If it was that bad it would still be around or in use.

Teak decks won't last for ever, they do wear out, but IMHO oxalic acid is less abrasive than scrubbing or power washing, and I'll continue to use it


Google: Oxalic acid teak

Or just look at the ingredient list of a lot of commercially available teak cleaners.

You don't have to listen to me, or follow my advice, but I know what's going on the teak in my cockpit next spring

 

[ksutton]

If I were new to boat ownership and a person who would prefer original looking teak to silver looking teak, lots of the comments on this post would scare the pants off me. However I have owned my present yacht for 7 years and have cleaned the teak annually with oxalic acid based products. In the first place to make it look original again and in the second place to stop the build up of acid rain which does make it look dirty when wet.
My teak is not damaged or heavily grained and I get many people asking if my yacht is new, and by the way still have more than enough time left to go long distance sailing.
As cleaning teak has no bearing on the yachts performance, I have a theory that a lot of owners don't clean teak for just that reason.
Before owning this present yacht, my previous yacht was 7 years old when I bought it from an "anti teak cleaner" it had the same appearance after 7 years of no cleaning the teak, than my present one has of 7 years cleaning.
Yes its hard work, but is very rewarding, if I was an anti teak cleaner I would probably select one of the many available yachts which don't have teak.
I would never criticise anyone for having silver looking teak on their boat, it obviously is pleasing to them and I have given up long ago trying to convert people, as there will always be owners with "wooden teak" who "wooden listen".

 

[Alrob]

where can we get oxalic acid from ???

 

[ksutton]

http://www.agwoodcare.co.uk/gbu0-prodshow/oxalic_acid.html

It will also remove rust stains from stainless steel and rust stains or yellowing from grp.