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02-04-2018, 12:59
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#1
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Registered User
Join Date: Feb 2015
Boat: HR 37
Posts: 36
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Suggestions for repairing UV damaged teak
I'm working on stripping the varnish off the teak handrails surrounding the companionway on my HR37, in an effort to repair years of UV damage. This is my first foray into this type of repair, and I've thus far been successful in using a heat gun to carefully remove the varnish. As shown in the photo, the bare teak has offsetting orange/brown and white spots that I'll need to try and remove before re-varnishing (previously coated in Epifanes). After taking the photo, I've also given the pieces a light sanding using 200 grit paper, but I still see the signs of damage.
What's the trick to get the bare wood back in spec before re-varnishing? Do I just need to sand more aggressively until a uniform surface appears? Can a bleaching product be used. Any assistance is appreciated.
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02-04-2018, 13:07
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#2
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Registered User
Join Date: Jul 2007
Location: Toronto, Canada
Boat: Luders 33 - hull 23
Posts: 1,787
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Re: Suggestions for repairing UV damaged teak
Can't see the details on top pic but for the bottom piece I would sand with 120, 150,180,220 and re-varnish - if 120 is not able to remove the stains, start with 80 then go to 120. Bleach removes the soft wood and leaves an uneven surface, sanding provides an even, smooth surface.
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02-04-2018, 13:10
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#3
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Registered User
Join Date: May 2014
Location: USA
Boat: 41' yawl
Posts: 1,187
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Re: Suggestions for repairing UV damaged teak
Quote:
Originally Posted by Tigidal
I'm working on stripping the varnish off the teak handrails surrounding the companionway on my HR37, in an effort to repair years of UV damage. This is my first foray into this type of repair, and I've thus far been successful in using a heat gun to carefully remove the varnish. As shown in the photo, the bare teak has offsetting orange/brown and white spots that I'll need to try and remove before re-varnishing (previously coated in Epifanes). After taking the photo, I've also given the pieces a light sanding using 200 grit paper, but I still see the signs of damage.
What's the trick to get the bare wood back in spec before re-varnishing? Do I just need to sand more aggressively until a uniform surface appears? Can a bleaching product be used. Any assistance is appreciated.
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Nice job with the heat gun, but make sure you don't linger too long and scorch the wood!
After stripping, I'd do as you suggest and sand way more aggressively (80-100 grit, with the grain obviously) then work back up to 220.
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02-04-2018, 14:57
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#4
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Registered User
Join Date: May 2017
Location: Maine USA
Boat: Gulfstar 41' ketch
Posts: 203
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Re: Suggestions for repairing UV damaged teak
I have always followed heat gun removal with chemical stripping. It will get the varnish in the grain and will avoid a blotchy looking varnish job later of course you still have to sand but no more than 120 grit. For a nice finish do 3 coats of varnish (don't have to sand as long as you recoat within 24 hrs) then sand to wood with 220. Then add 5 to 7 coats sanding lightly with 220 between each. Foam brushes are easiest but increase the number of coats if you use them.
Probably more than you asked for :-)
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02-04-2018, 22:13
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#5
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Moderator Emeritus
Join Date: Aug 2005
Location: Carlsbad, CA
Boat: 1976 Sabre 28-2
Posts: 7,505
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Re: Suggestions for repairing UV damaged teak
Oxalic acid is a wood bleach, the active ingredient in most teak cleaning compounds, available at any good chandlery. It comes in a powder that you mix with water and brush on the wood. Wash off before it drys. Will remove a lot of stains and great for getting rust stains off fiber glass as well.
You can sand the blemished wood but too aggressive sanding removes a lot of material. My newest boat has been sanded so many times the teak is less than 1/2 it's original thickness and needs to be replaced.
__________________
Peter O.
'Ae'a, Pearson 35
'Ms American Pie', Sabre 28 Mark II
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02-04-2018, 23:17
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#6
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Registered User
Join Date: Nov 2013
Location: Slidell, La.
Boat: Morgan Classic 33
Posts: 2,845
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Re: Suggestions for repairing UV damaged teak
For the life of me I can't see any damage in the first picture, even blown up to maximum, except maybe a scratch in the port side counter surface, so I assume it's shown as a reference?
As for the second picture, I don't see any damage in the wood itself, only the varnish covering it. Teak is a light colored wood, the 'dark spots' are likely the places where the varnish has soaked into the softer grain of the teak.
If you have some paint thinner, try rubbing it on the now-sanded surface and see if the 'white spots' disappear. It seems likely that you can remove the surface varnish as you have in the second picture, sand with 120-180, and varnish. If you want a mirror finish, after the second coat is truly dry, sand again as needed, finishing off with 300 or so to show where the surface deficiencies are, then it's the slog to build up enough thickness to level everything out, all the while keeping the developed thickness thin enough to not cause problems of its' own...seems somewhat of an exercise in futility to me, but then I'm a lazy slob for whom good enough is often good enough.
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03-04-2018, 05:46
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#7
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Registered User
Join Date: Feb 2015
Boat: HR 37
Posts: 36
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Re: Suggestions for repairing UV damaged teak
Thanks for the conversation and recommendations so far. As some have mentioned, the wood is in fine condition in terms of scratches etc and the finish is still very smooth. There is a surface crack in the veneer on the port side table that we have been able to sand out after stripping the varnish with a heat gun there as well.
The issue with all the companionway teak is the sun and refraction caused by the solid glass dodger on the HRs has caused the stain to darken in some areas and turn blotchy in others. I wish I had better photos with me but have added one more showing the fiddle while on the boat. The previous pics are actual, and not reference.
The goal is to return the wood (as best as possible) to its original condition before revarnishing.
It seems 3 options have been presented so far that I'll look more into...
1. Straight sanding, starting with a more coarse paper and working finer
2. Using oxalic acid to bleach the wood, followed by sanding
3. Using a paint thinner or stripper again now on the exposed wood, followed by sanding.
More conversation and recommendations are appreciated. Once I get the wood in shape I'll seek more input on the varnishing
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03-04-2018, 09:05
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#8
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Registered User
Join Date: Dec 2016
Location: East Coast UK
Boat: Colvic 40' Ketch
Posts: 277
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Re: Suggestions for repairing UV damaged teak
Quote:
Originally Posted by roverhi
Oxalic acid is a wood bleach, the active ingredient in most teak cleaning compounds, available at any good chandlery. It comes in a powder that you mix with water and brush on the wood. Wash off before it drys. Will remove a lot of stains and great for getting rust stains off fiber glass as well.
You can sand the blemished wood but too aggressive sanding removes a lot of material. My newest boat has been sanded so many times the teak is less than 1/2 it's original thickness and needs to be replaced.
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As above, I love oxalic acid on wood and fibreglass (it removes the brown oxide surface. but do a test patch first. I was about to re-varnish after doing the multi grit as other posters have suggested but I talked to a wood working expert and followed his advice instead.
I used Danish oil. Most modern varnishes that are water based are based on PVA so they are softer, the oil based ones do crack and flake, especially with UV and the wood warps if both sides are treated. I have used Danish oil on lots of woodwork, its easy and the results are brilliant. I was also advised not to treat the teak outside as once it goes gray its protected, otherwise you'll spend all your "sailing time" oiling the teak instead.
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03-04-2018, 10:16
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#9
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Registered User
Join Date: Jul 2012
Posts: 224
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Re: Suggestions for repairing UV damaged teak
I am a believer in teak guard. They have a cleaner that is blue. Wet with water, spritz. Wait a couple minutes and nylon brush and rinse. Has worked great for me. I really like the product for protecting the real. Haven’t sanded any in years an a new core of the real guard every six months ish keeps it like new.
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05-04-2018, 18:19
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#10
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Registered User
Join Date: Aug 2007
Location: Adelaide, South Australia, sailing in the Med.
Boat: Beneteau, Oceanis 50 G5
Posts: 1,295
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Re: Suggestions for repairing UV damaged teak
Quote:
Originally Posted by Tigidal
I'm working on stripping the varnish off the teak handrails surrounding the companionway on my HR37, in an effort to repair years of UV damage. This is my first foray into this type of repair, and I've thus far been successful in using a heat gun to carefully remove the varnish. As shown in the photo, the bare teak has offsetting orange/brown and white spots that I'll need to try and remove before re-varnishing (previously coated in Epifanes). After taking the photo, I've also given the pieces a light sanding using 200 grit paper, but I still see the signs of damage.
What's the trick to get the bare wood back in spec before re-varnishing? Do I just need to sand more aggressively until a uniform surface appears? Can a bleaching product be used. Any assistance is appreciated.
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We have tried a few teak treatments, and have found Semco to be outstanding. Once you have all of the varnish removed, if you use the Semco cleaner, it will remove any remaining traces (it is basically sodium hydroxide I understand), and clean up the teak, removing any mildew etc that has got through the degraded varnish.
Then the magic - the part two, Semco restorer. That will give you the 'wow factor' returning the bleached teak to the appearance of new teak (I suspect the part two is based on oxalic acid, but not sure).
Once you have washed that off thoroughly, let it dry, and sand to remove raised grain etc. You then have fresh, new teak, and the decision as to whether you want a rich, deep two-pack varnish look, or a natural teak look.
If you want to go for the natural teak look, then again Semco is the way to go, from our experience. It gives an appearance little different to fresh, new teak, but lasts a season or two, and then all you do is just wash, and recoat. Very quick and easy. We use it on our decks, which after seven years, still attract comments as to whether the boat is new.
There is a third option - a single-pack 'oil-varnish', and again, from our experience, 'Woodskin' (used to be known as Cetol Marine). You will not get the deep, rich, clear look of two-pack, but you will get a nice varnished look, with the advantage of the coating not flaking, but just slowly (over a couple of years) wearing away like an oil, so all you do is wipe over, a light sand, and another coat from time to time.
I hope that helps your decision.
David
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06-04-2018, 05:39
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#11
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Registered User
Join Date: Feb 2015
Boat: HR 37
Posts: 36
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Re: Suggestions for repairing UV damaged teak
Quote:
Originally Posted by David B
We have tried a few teak treatments, and have found Semco to be outstanding. Once you have all of the varnish removed, if you use the Semco cleaner, it will remove any remaining traces (it is basically sodium hydroxide I understand), and clean up the teak, removing any mildew etc that has got through the degraded varnish.
Then the magic - the part two, Semco restorer. That will give you the 'wow factor' returning the bleached teak to the appearance of new teak (I suspect the part two is based on oxalic acid, but not sure).
Once you have washed that off thoroughly, let it dry, and sand to remove raised grain etc. You then have fresh, new teak, and the decision as to whether you want a rich, deep two-pack varnish look, or a natural teak look.
If you want to go for the natural teak look, then again Semco is the way to go, from our experience. It gives an appearance little different to fresh, new teak, but lasts a season or two, and then all you do is just wash, and recoat. Very quick and easy. We use it on our decks, which after seven years, still attract comments as to whether the boat is new.
There is a third option - a single-pack 'oil-varnish', and again, from our experience, 'Woodskin' (used to be known as Cetol Marine). You will not get the deep, rich, clear look of two-pack, but you will get a nice varnished look, with the advantage of the coating not flaking, but just slowly (over a couple of years) wearing away like an oil, so all you do is wipe over, a light sand, and another coat from time to time.
I hope that helps your decision.
David
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Is this the Semco product you are recommending?... https://www.jamestowndistributors.co...o+Teak+Cleaner
I have used their sealer in the past, with mixed reviews.
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06-04-2018, 05:40
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#12
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Registered User
Join Date: Feb 2015
Boat: HR 37
Posts: 36
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Re: Suggestions for repairing UV damaged teak
Quote:
Originally Posted by rbrentp
I am a believer in teak guard. They have a cleaner that is blue. Wet with water, spritz. Wait a couple minutes and nylon brush and rinse. Has worked great for me. I really like the product for protecting the real. Haven’t sanded any in years an a new core of the real guard every six months ish keeps it like new.
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In researching my options, I cannot seem to find this one, or be certain of it... Can you provide a link? Thanks for the time.
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08-04-2018, 19:14
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#13
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Registered User
Join Date: Aug 2007
Location: Adelaide, South Australia, sailing in the Med.
Boat: Beneteau, Oceanis 50 G5
Posts: 1,295
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Re: Suggestions for repairing UV damaged teak
Quote:
Originally Posted by Tigidal
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That's the stuff (the cleaner and restorer - not the sealer).
The cleaner is harsh, but if you seal once all done, it should not need to be used again for quite some years (more than 5 years so far for us). It is so far the best we can find, and we get up to two seasons out of a single coating (note that we do use a winter cover)
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