Teak decks - again!

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davidej

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We have a Bene 361 with teak decks - ie a sort of ply insert which has a top veneer of teak about 4/5mm thick.

It has never had any treatmen (until now) except a wash with a mild detergent. However it has got really bad this winter and i have tried Patio Magic from B&Q, which previous threads have said is the same as Boracol (? spelling).

All the green had come off but there are still some patches mottled with brownish growths - see photo if it works.

Would another go with patio magic reduce this or do I need some more drastic treatment?

Suggestions welcome.
 
Patio Magic isn't the same as Boracol. Both contain an algaecide (benzalkonium chloride), which gets rid of the green stuff, but Boracol also contains a fungicide (disodium octaborate) which kills the mould. It's the mould which many people think is dirt, and scrub it off.

So the answer is to treat it with Boracol, or attack it with teak cleaner (which I would avoid as it'll erode the teak).
 
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I don't think that Boracol and Patio Magic have the same active ingredient. Boracol is probably some sort of borate (based on the name, but need to check) and uses benzalkonium chloride. So both would probably kill mould, algae and moss but not equally effectively. Patio Magic pretty much relies on benzalkonium chloride for effectiveness with algae.

No harm in trying more Patio Magic, can't say if Boracol would be better for the residual material you seem to have but I suspect that it might as Patio Magic is best with algae.

I couldn't make out much detail in the picture, looked like some sort of staining but you say it's a brownish growth.

If you can scrape it off a small area and leave clean teak then Patio Magic or Boracol might work.

If it seems to be below the surface you might have to try more drastic action. I try to avoid putting anything on teak as much as I can. I suspect that most proprietary cleaners contain oxalic acid so that's worth trying on a small area. I think that 2 stage cleaners may just be caustic based for the first treatment and oxalic for the second. I need to check as that's just a suspicion as I'd only use them as a last resort.

Hopefully someone else will recognise the brownish growth and have a good solution (no pun intended).

Update: Beaten to it. Typed too slowly and def. shouldn't have gone to make coffee before finishing.
 
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Since I have the Patio Magic, I have given it another go -in fact, two - with no discernable improvement.

It is definitely some sort of growth - possibly lichen - I am not an expert.

Boracol seems hideously expensive and, searching threads here, others have claimed that Polycell mould cleaner and various Wykes products contain the active ingredient. Does anyone know for sure?

Any suggestions, other than taking a scraper to it?
 
I have used Polycell mould cleaner successfully on similar stained teak. Harder work as you have to brush it in well then wash it off.
 
The most miraculous cure for a filthy teak deck that I ever saw involved a good dusting of Persil and a scrubbing brush (always across the grain) and rinsing with lots and lots of water. It might take a couple of applications to get all the dirt out but its dead easy and harmless.

I'd try that before spending out on marketed chemical-based "cures".
 
OK, Patio Magic was worth a try as you had it already. Not too surprised that a second application didn't work.

I was going to suggest Polycell 3 in 1 Mould Killer as it did contain Disodium Octaborate at one time. However, I've checked and found following in a UK HSE Non-gricultural Product Approval Document.

THE ACTIVE INGREDIENT HAS CHANGED FROM ‘DISODIUM OCTABORATE 2.93% w/w AND BENZALKONIUM
CHLORIDE 1.5% w/w’ TO ‘BENZALKONIUM CHLORIDE – 2.25% w/w ‘

If that's correct then it won't be any improvement on Patio Magic.

Look for something with borate on the label, probably disodium octaborate (but there are other related compounds). It might be worth looking at"Cuprinol Mould Killer" but I'm afraid that I don't know the composition.

If mould killer doesn't work then oxalic acid might be the next step. It won't particularly target mould but would help remove marks left behind by dead mould spores.
 
davidej said:
Since I have the Patio Magic, I have given it another go -in fact, two - with no discernable improvement.

It is definitely some sort of growth - possibly lichen - I am not an expert.

Boracol seems hideously expensive and, searching threads here, others have claimed that Polycell mould cleaner and various Wykes products contain the active ingredient. Does anyone know for sure?

Any suggestions, other than taking a scraper to it?
Click to expand...

Patio Magic takes a while to work. It seems to have killed the lichen, the brown growth, but it is still stuck to surface. Light scrape or wet brushing should remove it. Were the decks dry when you applied PM?, unlikely this time of year.
 
Use Boracol, you don't need to scrub or scrape - and that's what does the damage to the teak.

It needs doing every 6 months - March and Sepetember, but wipe it on and leave for 10 days and the teak comes up the silvery brown colour,

I did have some areas tlast year that didn't change completely, typically this was the end grain of the grab rails, another wipe on these areas solved it.

Please don't use Oxalic acid - that takes off the top layer of the teak - it literally burns it off !
 
davidej said:
We have a Bene 361 with teak decks - ie a sort of ply insert which has a top veneer of teak about 4/5mm thick.

It has never had any treatmen (until now) except a wash with a mild detergent. However it has got really bad this winter and i have tried Patio Magic from B&Q, which previous threads have said is the same as Boracol (? spelling).

All the green had come off but there are still some patches mottled with brownish growths - see photo if it works.

Would another go with patio magic reduce this or do I need some more drastic treatment?

Suggestions welcome.
Click to expand...

DO NOT DO NOT USE PATIO MAGIC... unless you want to completely ruin the deck, its made from a living wood not concrete!!

Would recommend TEAK WONDER here: http://www.teakwonder.co.uk/ no connection other than a satisfied customer.

There is another I have used also very good, trying to remember the name, it is also a two stage product made by Wessex chemicals.

Never use anything harder than a sponge when cleaning your teak, brushes are for other surfaces not teak.
 
I wrote a long teak cleaning piece a while back

Mildest is seawater. Next up are patio cleaner things, usually "bio" these days and not the fizzing things or yore. More caustic is dishwasher powder - wet the teak. bosh around a bit of loose dishwasher powder, and that will bring teak up nicely. Some single part teak claners are mild oxalic acid, and that's not too bad but no ace. Heavier duty is two-prt teak cleaner such as Florida or Wessex Chemicals and these make the teak look even better than when just sanded. The second part is oxalic acid which is also a rust remover. These erode the silver-grey teak surface - they erode the grey oxide layer. Like a potato goes brown if you leave it in the open air, so teak oxides (more slowly) and the softer parts more quickly, and get wasked away ( a bit) hence the ridging of caulk being the high points and then the hard fibres.

To bring old teak back to new, you sometimes need to sand it. Mask off all around and make happy with a sander of you choice. Doing it by hand is safest, but an orbital of dick sander will be quicker. If you know what you're doing, you get make short work of it with 60 grit discs- yeah they sound and feel scary rough but the teak comes up much smoother than the paper. Or use 80 or 100 which many people do, and it takes ages. You only need to get the stuff flat ISH - the less you take off obviously the better. I spose you could use 60 grit first to get some stuff off, then smooth with 100. Once sanded, unles you've gone mad and fully sanded the whole thing down, there'll be some bits nice anew sanded, others bit older. Give it a few days or a week to all go about the same colour, and then do the two-part teak thing. The more sanding and two-part the nicer the teak will look.. and the shorter time it will last. Best of course er don't have teak or cover the stuff. Or just do it evry other year. The dishwasher powder is ok a few times a season tho, much easier on the wood.
 
Force 4 do, what looks like wirewool, but isn't. Costs about £12 and I can't see it on their website at this time. Removes the sort of ingrain you appear to have but doesn't remove the teak - quite hard work but it's good.

You could try the Persil approach, but I would recommend dishwasher powder (probably very similar). Mix up a warm slippery solution and drip it over some teak and leave for 5-10 mins, then with a real soft brush more of the liquid with a gentle action across the grain; leave for another 10mins and then rinse off.
 
angelsson said:
DO NOT DO NOT USE PATIO MAGIC... unless you want to completely ruin the deck, its made from a living wood not concrete!!

Would recommend TEAK WONDER here: http://www.teakwonder.co.uk/ no connection other than a satisfied customer.

There is another I have used also very good, trying to remember the name, it is also a two stage product made by Wessex chemicals.

Never use anything harder than a sponge when cleaning your teak, brushes are for other surfaces not teak.
Click to expand...

Why the aversion to Patio Magic are you confusing it with other products containing hydrochloric acid? I'm not certain how Patio Magic would attack teak, can you provide any evidence (scientific or anecdotal)?

Which Teak Wonder product are you suggesting (there are at least 3) and I imagine you mean the cleaner. I'm certain that the products do work as they contain the type of chemicals you'd expect. Probably explains why some people find that dishwasher powder works well.

Teak Wonder Cleaner: RRP ~£32 4ltr
Sodium metasilcate, strongly alkaline (used in dishwasher tablets/powder)
Sodium Dodecylbenzosulphonate (surfactant, probably found in fairy liquid & similar)

Teak Wonder brightener: RRP ~£32 4ltr
1%-10% Hydrochloric acid + some Oxalic acid (quite similar to patio cleaners, so if anything, more likely to damage teak than Patio Magic)

Teak Wonder Sealer: RRP ~£63 4ltr
A sort of teak oil with Kerosene, Linseed oil, a cresol, etc.


tcm's post gives an extemely good summary regarding teak cleaning. I don't really regard Patio Magic as being much of a teak cleaner. The active ingredient basically just targets algae (& mould to some extent). So it gets rid of green slime and slows down regrowth.
 
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davidej said:
Boracol seems hideously expensive and, searching threads here, others have claimed that Polycell mould cleaner and various Wykes products contain the active ingredient. Does anyone know for sure?
Click to expand...

Before using Boracol, I used the Polycell product, and frequently recommended it on here. However, as others have said, it was reformulated about a year ago and no longer contains disodium octaborate.

As an alternative to Boracol, you might try Wikabor which is a bit cheaper. However, it does have a slight blue tinge, although I don't think that would be noticeable on the deck. I've been using it on teak garden furniture successfully.

All the patent "cleaners" tend to be acid-based and will inevitably remove wood. The Boracol (or similar) route is the only way to keep the deck looking good without constantly destroying the top surface of the teak.
 
Mistroma said:
Why the aversion to Patio Magic are you confusing it with other products containing hydrochloric acid? I'm not certain how Patio Magic would attack teak, can you provide any evidence (scientific or anecdotal)?

Which Teak Wonder product are you suggesting (there are at least 3) and I imagine you mean the cleaner. I'm certain that the products do work as they contain the type of chemicals you'd expect. Probably explains why some people find that dishwasher powder works well.

Teak Wonder Cleaner: RRP ~£32 4ltr
Sodium metasilcate, strongly alkaline (used in dishwasher tablets/powder)
Sodium Dodecylbenzosulphonate (surfactant, probably found in fairy liquid & similar)

Teak Wonder brightener: RRP ~£32 4ltr
1%-10% Hydrochloric acid + some Oxalic acid (quite similar to patio cleaners, so if anything, more likely to damage teak than Patio Magic)

Teak Wonder Sealer: RRP ~£63 4ltr
A sort of teak oil with Kerosene, Linseed oil, a cresol, etc.


tcm's post gives an extemely good summary regarding teak cleaning. I don't really regard Patio Magic as being much of a teak cleaner. The active ingredient basically just targets algae (& mould to some extent). So it gets rid of green slime and slows down regrowth.
Click to expand...

Also the run off from the two part Wessex Cleaner can make a bit off a mess of the gel coat finish, particularly on coloured hulls.
 
pvb said:
Hope you're not planning to keep the boat for long...
Click to expand...

+1 Scrub? Anyway, no scrubbing needed if the product is an algaecide, just leave it for a couple of weeks. What's in it anyway, is it a cleaner or for algae & mould removal?

I've seen things such as Ronseal teak cleaner at B&Q. It contains Alkyldimethylbenzylammonium chloride which is closely related to benzalkonium chloride. I suspect that's the active ingredient in most common algaecides and I just look for best value wrt concentration in product. I haven't seen their own B&Q product.
 
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