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What Is This Coating?


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 have posted this video here before on my restoration thread but as happens, the subjects got muddled by distraction and there was no solution offered. After my recent visit I have decided to prioritise sealing the deck around the rear so I would like to ask again.

The video was shot a couple of years ago just after I got the boat. I mention the grain on the coating but this is obviously the inprint from the teak; an idiot should have known that!

I also say it's not epoxy but again, that could be rubbish too. Having looked around a bit I wonder if it's polyurethane. I have contacted Sika and they say they don't have a product suitable to do the job, just the sealants.

The present coating covers all the deck planking and edging. It's obviously been there for a good few years.

I don't expect anyone to be able to say exactly what it is but I would welcome suggestion as to how I may find an alternative product. I wonder if a visit to somewhere like Martham Boats is on the cards?

Thank you in anticipation.

I don't know why there is a blank video here, just ignore it and it'll probably go away....:default_mellow:

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its probably something like yacht varnish, just lots and lots of coats, if its any consolation Water Rails mast seems to have used something similar, and that took a lot of sanding to remove to get back to the wood.

Tough stuff, but once it starts peeling it all needs to come off and be replaced.

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It lookslike it could be a natural finish, high build Shellac type. Shellac is normally soluble to Alkaline. Try a little ammonia and see if it dissolves.

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4 minutes ago, Vaughan said:

At a guess, it is Fibreglass resin.  In those early days of GRP, there were one or two "miracle cures" done on wooden boats by Fibreglass sheathing. I don't think I ever saw one that worked!

Don't you think it might be a bit too flexible for grp resin, Vaughan ?

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I agree with the high failure rate of fibreglass sheathing. One of the big problems prevalent in the 70s and early 80s was the addition of "Talc" in large quantities to the resin. This was done to achieve a fine finish prior to painting and was a practice copied from the specialist body repairers of "cars of the day" Marcos, Lotus, TVR, Gilbern etc but if the subsequent paint was compromised it was fairly porous.

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31 minutes ago, ChrisB said:

Don't you think it might be a bit too flexible for grp resin, Vaughan ?

I am talking of resin rather than gelcoat. It is a lot more flexible than one might think, especially with only a very thin coat, such as this.

I presume it hasn't stuck as teak has natural oils. Another reason why it is not an easy wood to varnish.

Edited by Vaughan
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I dont think it's either polyester resin or epoxy resin as they are both far more brittle when cured. 

The way it flexes when you are pulling it up suggests something single pack either single coat or multiple layers built up. 

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Blimey, some of you get up early don't you? Thanks for all the ideas, they are all valuable.

A couple of my own thoughts: it is flexible which is why I thought it wasn't resin. It HAS actually stuck to the deck but has come unstuck where the water has got underneath, probably due to damage/penetration. But it is easy to peel off. I am now wondering if the deck is actually teak? Could it be another hardwood and the covering is there as part of the combination for an overall effect? 

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It is a product called Coelan (very expensive) It forms a very thick protective coating that can last for ten years however as in this case if water gets under the edge it will peel off in sheets.

Robin

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Just a bit more information regarding Coelan

It is a polyurethane type of varnish, the wood has to be clean and dry then sanded with nothing finer than 60 grit followed by a primer coat, Then six coats of clear Coelan varnish you do not sand between coats.

If this system is applied correctly you end up with a very durable high gloss protective  coating which can last over ten years however as stated previously if water gets under the edge it will peel off.

If you like the sound of this for your boat i would recommend you are sitting down with a large drink in hand when asking for a quote. 

The primer coat costs about £25 per sqm followed by six coats at about £85 per coat per square meter. plus labor.

Robin

 

 

 

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2 hours ago, Robin said:

Just a bit more information regarding Coelan

It is a polyurethane type of varnish, the wood has to be clean and dry then sanded with nothing finer than 60 grit followed by a primer coat, Then six coats of clear Coelan varnish you do not sand between coats.

If this system is applied correctly you end up with a very durable high gloss protective  coating which can last over ten years however as stated previously if water gets under the edge it will peel off.

If you like the sound of this for your boat i would recommend you are sitting down with a large drink in hand when asking for a quote. 

The primer coat costs about £25 per sqm followed by six coats at about £85 per coat per square meter. plus labor.

Robin

 

 

 

Oooouch!

Thank you Robin, I believe you are spot on. I have downloaded the factsheet and shopped around a bit. It's not quite as bad as you say though: £240 for 3 litres which covers 3 x 10sq ft (US factsheet) with all 6 coats. But still not cheap and when I add the cost of the Sikaflex 290 for the gaps....

The factsheet clearly states it can be applied over teak.

I guess that's why a previous owner had a full cover made for the boat as a slightly less expensive option.

Of course there are cheaper options but that would ruin the character of the boat. I'll do a bit of maths and a bit of thinking and see what I can come up with. My first thoughts are that maybe the way to go would be to do it in small sections and see if I can get a good match with the areas which are still ok.

In appreciation of the forum I've just purchased nice forum flag for my 6ft pointless mast.

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As Vaughan said teak is not easy to varnish. Whilst a lot of effort will be required to clean it back to bare wood is the answer to simply oil it ultimately? It will need to be reoiled frequently I expect but finishes like polyurethane are great forever internally but I’ve seen issues when used externally where accident damage has subsequently occurred, moisture has got in and difficulties arise trying to blend in new with old. 

Im sure however you decide to finish it it’ll look smart, nice design of boat!

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1 hour ago, Turnoar said:

As Vaughan said teak is not easy to varnish. Whilst a lot of effort will be required to clean it back to bare wood is the answer to simply oil it ultimately? It will need to be reoiled frequently I expect but finishes like polyurethane are great forever internally but I’ve seen issues when used externally where accident damage has subsequently occurred, moisture has got in and difficulties arise trying to blend in new with old. 

Im sure however you decide to finish it it’ll look smart, nice design of boat!

Vaughan's words of wisdom are always most welcome on my threads and I also appreciate how much the teak deck adds to the boat. I also love the smell of teak oil if that's the stuff to use!. However, if I experiment with oil first there will be no chance at all of anything else sticking to the wood afterwards so I'll go with the Coelan first I think.

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5 hours ago, floydraser said:

if I experiment with oil first there will be no chance at all of anything else sticking to the wood afterwards

I don't think that would be a problem.

A lot of ocean yachts with teak decks leave them in bare wood and they are then scrubbed every few days and oiled often.  That's fine if you have a paid crew.  The big thing about a bare teak deck on a yacht is that it is non slip and most traditional crews will sail in bare feet.

The trick when applying paint or varnish to any wood is to scrape it right back to the bare wood before you apply it.  If you try to put new varnish on what is left of the old coats, even after sanding, you are wasting your time.

We used to varnish teak by rubbing in two coats of linseed oil with a rag, followed by a first coat of half and half varnish and turps (not white spirit). The first coat probably won't dry out fully but don't panic! The second coat will dry out the first one.

Ideally I would sand the deck right back to bare wood and then oil it. Unless this film of plastic was put on to hide other problems such as leaks? In which case better to find the problem and cure it, rather than cover it in resin and hope for the best.

What the French call a "Cache misère".

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10 minutes ago, Vaughan said:

Unless this film of plastic was put on to hide other problems such as leaks?

I have just read your other thread and perhaps my suspicions may be confirmed.

In your photo there appears to be an area around the mooring cleat which has been repaired with short planking. Perhaps best to start looking there. Hopefully it may just be a matter of re-pitching the seams. In which case don't try to do that yourself!

Talking of scrubbing decks, I have just remembered an old ditty from the Navy :

For six days shalt thou labour and do all that thou art able.

And on the seventh day, thou shalt holystone the deck and chip and scrape the anchor cable!

Edited by Vaughan
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3 hours ago, Vaughan said:

I don't think that would be a problem.

A lot of ocean yachts with teak decks leave them in bare wood and they are then scrubbed every few days and oiled often.  That's fine if you have a paid crew.  The big thing about a bare teak deck on a yacht is that it is non slip and most traditional crews will sail in bare feet.

The trick when applying paint or varnish to any wood is to scrape it right back to the bare wood before you apply it.  If you try to put new varnish on what is left of the old coats, even after sanding, you are wasting your time.

We used to varnish teak by rubbing in two coats of linseed oil with a rag, followed by a first coat of half and half varnish and turps (not white spirit). The first coat probably won't dry out fully but don't panic! The second coat will dry out the first one.

Ideally I would sand the deck right back to bare wood and then oil it. Unless this film of plastic was put on to hide other problems such as leaks? In which case better to find the problem and cure it, rather than cover it in resin and hope for the best.

What the French call a "Cache misère".

Thanks again Vaughan. I have always accepted that the seams will need to be resealed and after that process we will be back to bare wood. I wouldn't try to go over the old varnish as it is discoloured and worn in a lot of places. However, I would try to butt up to it in stages if possible. It wouldn't be practical for me to do the whole deck in one go.

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Having given it a bit more thought I think I have a way forward: The application of Coelan is going to be the ultimate goal but how much of it do I need and for what area? Well I won't know the answers until I've done all the repair work to the decking and if I do that work in stages and apply it as I go, I am likely to end up with half empty tins in storage or not enough for a full coat.

I think therefore, the best way forward may be to strip back the old covering where it's failed, make good the timbers involved and apply oil as Vaughan suggests. This may result in the repaired areas showing up around the deck but once all the repairs have been done I could then go back and apply the Coelan. In practise, the time between the last oiling and the Coelan going on could be a season or two. It would mean I could calculate more accurately the amount needed and prevent expensive waste. Does that make sense?

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