Restoring long neglected teak trim - stupid question

Yngmar

Yngmar

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I'm entering the wonderful world of varnishing (coughs up a cloud of teak dust). I've played with a test piece and already learnt a lot about wrinkles, alligators, drying times, dust, bubbles and the "quality" of cheap varnish with pictures of boats on the tin. I've also played with epoxy under varnish (still undecided on that one, but I think I'll skip it due to high risk of having to sand it all off again).

As I've also learnt, before the varnishing comes the sanding. Which I've done a bit today, and the pieces I've sanded are cockpit teak trim that has been long neglected and may not have been varnished in 15 years (if ever). It is therefore grey, worn and has fairly deep structures where the wood has weathered away.

After some sanding, it looks like in this photo (the other one being before sanding, for comparison):
teak_trim.jpg


The question is, what do I do about the deep grey grooves that remain in the sanded piece? Do I keep sanding, losing significant thickness (this may work on these pieces, but not others)? Is there some way to revive the stuff or make it go teak coloured again prior to varnishing? I know from my experiments that simply varnishing over it will not revive it very well and the grey streaks remain somewhat visible. Do I just live with that or what are my options here?
 
Oxalis acid or products that contain it will go a long way towards restoring the colour. In the end, you are probably better off not varnishing teak, using one of the oils or products that give a similar effect more durably.
 
johnalison said:
Oxalis acid or products that contain it will go a long way towards restoring the colour. In the end, you are probably better off not varnishing teak, using one of the oils or products that give a similar effect more durably.
Click to expand...

Do not use oil if it is going to be exposed to the elements as it evaporates and needs constant topping up. some oils also leave a sticky residue and attract more dirt.

Worth having a go with the Wessex Chemicals 2 stage teak cleaner (came out top in the recent PBO test) before sanding as that will remove most of the grey. Contains oxalid acid and some other magic ingredients. This may reduce the amount lost through sanding.

Either leave it bare, invest the time and effort into conventional varnish or get into the technological age and use a porous woodstain such as International Woodskin.
 
Tranona said:
Do not use oil if it is going to be exposed to the elements as it evaporates and needs constant topping up. some oils also leave a sticky residue and attract more dirt.

Worth having a go with the Wessex Chemicals 2 stage teak cleaner (came out top in the recent PBO test) before sanding as that will remove most of the grey. Contains oxalid acid and some other magic ingredients. This may reduce the amount lost through sanding.

Either leave it bare, invest the time and effort into conventional varnish or get into the technological age and use a porous woodstain such as International Woodskin.
Click to expand...
woodskin does work & easy to make good, shame it has a hint of stain / colour in it
 
Excellent, I have some oxalic crystals, will give it a try in an inconspicuous area and report back.

Not interested in oils or Woodskin/Cetol, already evaluated and discarded those options and decided on varnishing the cockpit trim.
 
Wessex 2 pack then Semco ...

Before



During ...



After (Semco being applied) ...



6 months later it still looks like it has just been done, although I am re-coating the Semco every 6 months - massively cheaper than a new teak deck.
 
chinita said:
You say 'teak trim' so, presumably not large areas. Therefore no need for wholesale chemical, and potentially damaging, treatment.

Forget sanding. It is the devil's spawn and merely clogs the grain.

Hard work on the thumbs, but the answer is this:

https://www.classichandtools.com/acatalog/Hand-Scrapers.html

The result is in a different universe to sanding.
Click to expand...

Nope, not large areas, just trim. This is very interesting! Now we're definitely expanding my horizon. Would this work on curved pieces, as some of the cockpit trim is shaped (steam bent I think)? I guess the curved ones would.

But unless you suggest scraping out the weathered grooves with it, it doesn't really solve my problem, does it?
 
Yngmar said:
Excellent, I have some oxalic crystals, will give it a try in an inconspicuous area and report back.

Not interested in oils or Woodskin/Cetol, already evaluated and discarded those options and decided on varnishing the cockpit trim.
Click to expand...

In that case why ask for and then reject advice?

Our boat has a large area of teak trim-5 inches wide-all around the boat, plus two large tapering sections around the cockpit.

International Woodskin was used 5 years ago and it has not been touched since. It is fair to say it needs re-doing this year. For 3 seasons it looked great, last year a bit edgy and after this winter I really must do it again.

It works for me!
 
Yngmar said:
Nope, not large areas, just trim. This is very interesting! Now we're definitely expanding my horizon. Would this work on curved pieces, as some of the cockpit trim is shaped (steam bent I think)? I guess the curved ones would.

But unless you suggest scraping out the weathered grooves with it, it doesn't really solve my problem, does it?
Click to expand...

Chemical treatment may restore the teak colour but it won't remove the grooves. Fine if you can live with the grooves.

What I am saying is that sanding wood gives a false impression and does not result in a smooth, flat surface. No matter how careful you are sanding (by hand or machine) there will be undulations.

I say this from my experiences at Boatbuilding College where sandpaper was only used for specific purposes - never used when preparing any wood for varnishing. Burnished Swedish scrapers were used - even mounting the scraper in a Veritas holder was frowned upon. Had to be thumb power!

The results of this method came as a revelation to me.
 
Another vote for the Wessex Chemical 2 stage cleaner. I have tried them all and it beats them hands down. A neighbour, on my recommendation, recently tried it on slatted cockpit seats and was delighted with the results including the slots between the slats.
 
Being essentially lazy, I've always been a fan of letting teak go gently sandy-grey, and using Boracol to keep algae and mould at bay (tiny mould spots are the "dirt" that people scrub off teak). It's very low maintenance, and doesn't involve scouring away layers of valuable teak.
 
pvb said:
Being essentially lazy, I've always been a fan of letting teak go gently sandy-grey, and using Boracol to keep algae and mould at bay (tiny mould spots are the "dirt" that people scrub off teak). It's very low maintenance, and doesn't involve scouring away layers of valuable teak.
Click to expand...

Letting it go grey is what I'm happily doing with the teak deck, and using Lidl biocide spray to keep the green away instead of Boracol, but this thread isn't about the teak deck.

It's about the cockpit teak trim, and the grey there doesn't work for me or for the boat, the teak is badly weathered and starting to crack and splinter in places (especially the curved parts). So the reason for varnishing is to extend it's expected service life, at the cost of a one time scouring away of layers (most of the trim is reasonably thick, much thicker than the decking) and in the future a gentle sanding (of varnish) before adding a new layer on top.

I've applied some oxalic acid today and left it on for 15 minutes. Still waiting for it to dry to see the results. It certainly cleaned the pontoon planks up well (you're welcome, Premier). Also removed some rust stains from the gelcoat while I was a it - useful stuff. A can of Le Tonkinois should be arriving shortly too.
 
Yngmar said:
Letting it go grey is what I'm happily doing with the teak deck, and using Lidl biocide spray to keep the green away instead of Boracol, but this thread isn't about the teak deck.

It's about the cockpit teak trim, and the grey there doesn't work for me or for the boat, the teak is badly weathered and starting to crack and splinter in places (especially the curved parts). So the reason for varnishing is to extend it's expected service life, at the cost of a one time scouring away of layers (most of the trim is reasonably thick, much thicker than the decking) and in the future a gentle sanding (of varnish) before adding a new layer on top.

I've applied some oxalic acid today and left it on for 15 minutes. Still waiting for it to dry to see the results. It certainly cleaned the pontoon planks up well (you're welcome, Premier). Also removed some rust stains from the gelcoat while I was a it - useful stuff. A can of Le Tonkinois should be arriving shortly too.
Click to expand...

IMHO Le Tonk is a good choice if you want to go down the varnish route. You don't need to sand between coats but, be aware, it will take around five coats before you start to see any meaningful gloss. After that the results are impressive.

A final tip. If, after your final coat, you still see minor specks of dust the way to get rid of them is by rubbing with the REVERSE side of a sheet of sandpaper. There is sufficient abrasion on that side to remove dust without abrading the surface.

Taught to me by a carpenter of sixty years experience.
 
Whatever you decide, a cockpit cover is a good plan to ensure you do not have to do it again for many years. Here is a snap of a corner of my cockpit:

View attachment 57065

Well it's just cheapo woodstain but the point is the original inset ply is coming up forty years old and that is a key wear area; a cover keeps the sun and rain off.
Same with my properly varnished washboards and tiller which I have re-varnished only once in 20 years.
 
I have been using Ronseal water based varnish - available in clear or wood tints. Its middle ground between oils and conventional varnishes in my view.

Pros: Easy to apply - no runs or sags, lasts for about 3years in a marine environment, easily sanded off, can be recoated or touched up. Water / moisture cannot get under it and cause black stains.
.
Cons: Not tough enough for walking on, satin finish might not be what you want. Doesn't last for the claimed 5years.

I'd suggest a trial and also not worry too much about the grey bits. My handrail and toe rails are 35years old and came up well after sanding and then Ronsealing 6 years ago. They need a repaint this summer, but otherwise I am happy with the result.
Ian
 
This is the same piece as the bottom one in the first post, after applying maximum strength oxalic acid for 15 minutes:
ox2.jpg


Not a good comparison, because the first shot was done in bright sunlight, which is unfortunately unavailable today. I'd say the improvement is perceptible, but not hugely so. The oxalic acid was not at fault, it worked great at cleaning up pontoon planks and removing rust stains from the gelcoat (boatyard gifts from a steel boat).

So I think this leaves me with two options, sanding/scraping off another 1-2 mm of wood until I've reached the bottom of the grey grooves, or say screw it and varnish over it (probably requiring additional layers and sanding to become even).

Comparison shoop (mind you, light was different, meh):
teak_compare.jpg
 
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