Removing Semco Teak Sealer

[Railbob]

Hi,
I've recently purchased a newish yacht which has arrived up here a couple of weeks ago. Like all boats she's needing some TLC on her, one of which is that the cockpit seating has been coated with what looks like Semco, this is now a bit tired looking and I'm planning on how to clean back so it can be recoated. I'm loathed to use any form of sanding on it, does the cleaner/renovator remove the old coating or am I going to have to sand it very lightly?

Many thanks in advance
Railbob

 

[ashtead]

If it is Semco it does need renewing annually in UK climate or more often if in sunnier climbs. Usual teak cleaner 2 part products takes it back to the clean wood ( there is a good set of photos of this rejuvination from a mobo on this forum after a reapplication) but if you are concerned at using that due to chemicals and mess you could try removal with a green meanie and soapy water as a starter on part of seating. I hate to mention in same sentence as teak but a low pressure power washer with the rotary head attachment would no doubt have same effect as well (not of course I suggesting you try it )

 

[maby]

Any idea how many coats of Semco it has had over the years and how long since the last coat? Generally speaking, there is no need to remove Semco each year - just give it a good wash with a mild soap, let it dry and apply another couple of coats. They do recommend stripping back every few years with a standard two-part teak cleaner like Wests or Semco's own brand. Ours is looking a bit tired and in need of a bit of TLC - as soon as the weather dries up a bit. I will give the entire deck a good wash with a mild shampoo in a bucket of warm water using a very soft deck brush. I will then go over it all with Patio Magic or Boracol to get any mold out, then apply a couple of coats of Semco. The only exception is the cockpit - that has got quite dirty and I will probably give it the full treatment - teak cleaner, teak restorer and Semco.

 

[Railbob]

Any idea how many coats of Semco it has had over the years and how long since the last coat? Generally speaking, there is no need to remove Semco each year - just give it a good wash with a mild soap, let it dry and apply another couple of coats. They do recommend stripping back every few years with a standard two-part teak cleaner like Wests or Semco's own brand. Ours is looking a bit tired and in need of a bit of TLC - as soon as the weather dries up a bit. I will give the entire deck a good wash with a mild shampoo in a bucket of warm water using a very soft deck brush. I will then go over it all with Patio Magic or Boracol to get any mold out, then apply a couple of coats of Semco. The only exception is the cockpit - that has got quite dirty and I will probably give it the full treatment - teak cleaner, teak restorer and Semco.

Unfortunately I have absolutely no idea of the number of coatings it's had, I don't think she's been recoated very recently as she's been on the hard for quite a while by the look of her condition. She has been looked after well and didn't need much work apart from some cosmetic work which I'm getting around to doing. I have the cleaner and renovator from Teak Wonder so I'll give that a try in a small area first.

Railbob

 

[maby]

I don't know the Teak Wonder cleaner - to remove Semco you need to use a two-part cleaner where the first coat is a fairly strong acid and the second part is an equally strong alkaline. Typically, the first application is oxalic acid and the second application is sodium hydroxide. It's nasty stuff and has to be handled with some care.

 

[Railbob]

I don't know the Teak Wonder cleaner - to remove Semco you need to use a two-part cleaner where the first coat is a fairly strong acid and the second part is an equally strong alkaline. Typically, the first application is oxalic acid and the second application is sodium hydroxide. It's nasty stuff and has to be handled with some care.

Hi Maby,
The stuff I have is a two part thingy :encouragement::encouragement: If what you are saying about it correct ( haven't had a chance as yet to look at the bottles) then I'll certainly take care using it, thanks for the heads up :encouragement:

Railbob

 

[superheat6k]

I have found that too much Semco tends to make the deck look a bit dull and the surface starts to look uneven. Wessex two pack on the affected areas, e.g. high traffic after 18 months and four coats. I am now limiting how much I put on on the low traffic areas.

The results using Wessex & Semco are startling. I favour Patio Magic to keep the green at bay.

 

[Railbob]

I've had a look at the Semco Teak sealer and it varies from nonexistent to several coats. I'll have to go wary on it when using the cleaner and renovator. I may try and lightly use some wire wool where it looks thick. Has anyone done this?

 

[maby]

I've had a look at the Semco Teak sealer and it varies from nonexistent to several coats. I'll have to go wary on it when using the cleaner and renovator. I may try and lightly use some wire wool where it looks thick. Has anyone done this?

Those teak cleaners are intended for bare wood, so I don't think you need to be too paranoid about it. The instructions tell you to apply to a small area - no more than a couple of square metres - at a time, let stand for the recommended period, then rinse off very thoroughly before treating the adjacent area, repeating if necessary on wood that is particularly dirty. If I were you, I would just use teak cleaner, initially concentrating on the areas that have a significant thickness of Semco and moving on to the thinner (or bare) areas once you have got the thick stuff off.

The cleaners are quite corrosive, so make sure you rinse very well. They are not toxic in the usual sense and are not going to harm marine life provided you are not sitting in an area with little current flow - so long as it is well diluted, it is not poisonous. Do try to avoid contact with your skin or any metal work on the boat - and rinse very quickly and thoroughly if you do get it somewhere where it should not go.

 

[superheat6k]

I would not use non stainless steel wire wool, small particles will break off and then rust in the grain. However, Wessex works well with just a gentle scrub. The red first acidic coat can be unpleasant to the nose and splashes do sting and need washing off. Old clothes, gloves and goggles.

 

[Railbob]

I would not use non stainless steel wire wool, small particles will break off and then rust in the grain. However, Wessex works well with just a gentle scrub. The red first acidic coat can be unpleasant to the nose and splashes do sting and need washing off. Old clothes, gloves and goggles.

Thanks everyone, so it's on with the old noddy suit then?

 

[maby]

Thanks everyone, so it's on with the old noddy suit then?

Certainly take sensible precautions. Goggles are probably the most important - it would take several minutes to do serious damage to your skin, but a small splash in the eye could be very painful and leave you in need of medical attention almost instantly. Have a hose or bucket of water handy at all times to rinse off any splashes from your skin promptly.

 

[ashtead]

Thick washing up gloves , a small scrubbing brush as used for hands not decks as you don't really need to scrub that hard and some glasses should be fine along with paper decorating suit is usual gear but if you prefer something more colourful with a bell on your head I'm sure it won't harm but head covering not strictly required. Main thing is not to let the cleaner dry so a running hosepipe handy helps . It helps if not a hot sunny day as well .