sanding teak decks

[tckearney]

Hi All, I'm thinking of selling my boat and want to get it tip top condition before any survey.   A few items I feel need addressing.  One is the Teak decking.  The Port side is fine but the stbd side has a few seeps coming back through the caulking after rain.  I am therefore thinking of recaulking the decks.  I will be getting a Joiner to do it.   Has anybody done this.  The teak has never been sanded and is 19 years old.  It looks good but is grainy.  The caulking is raised above the teak.  I think the teak may have been power washed a few times and this has removed the soft outer surface.   There seems to be plenty of teak available  (4mm or 5mm) . So My plan was to belt sand it remove caulking and recaulk.  Then sand flat again.  What is the best caulking?  I know there are plenty of new waterproof silicone based products around now like CT1 and HB2 but what is best.  Anything I should watch for.   I am on a tight budget as other things may also need attention. 

[tiger79]

I did this on my previous boat, a 20 year old Hallberg-Rassy.  It's a huge job!  The best way is to start by trimming off excess caulking with a chisel or a scalpel-like craft knife.  Be very careful sanding - even a lightweight DIY belt sander can be quite aggressive.  You'll need a small triangular sander to get into some areas which the belt sander won't reach.  For re-caulking I used Sikaflex, and treated the grooves with Sikaflex Primer first to ensure good adhesion.  Ideally, use masking tape on both sides of each groove, to minimise the amount of caulking you get on the teak.  Have a decent-sized cardboard box on deck to drop the used masking tape into as you remove it - a brick in the bottom of the box will stop it blowing away!

[Yngmar]

Sounds like you need to recaulk the thing, which is a lot of work (or money if you get someone else to do it). When doing so, do not sand twice! It causes a lot of extra work and you lose more of the teak than necessary that way. Remove the old caulking. Plenty instructions on the internet for it - spending on the special angled tool to scrape it out is worthwhile if you're doing the whole deck. Then recaulk, flattening the caulk with a putty knife (yes, smearing it all over the teak). After it's well and truly cured (a week at least,  probably longer depending on temperature and humidity - see data sheets), you can then sand the deck until all the smeared caulking is gone, which means you have also smooth, nice teak left now. This way you only have to mask the edges of the teak, not every seam.

Use TDS-SIS 440 or any other MS polymer based deck caulking. Would advise against Sikaflex 290DC, as it requires primer and uses outdated PU chemistry, which costs more and gives worse results (poor UV resistance).

[tiger79]

Sounds like you need to recaulk the thing, which is a lot of work (or money if you get someone else to do it). When doing so, do not sand twice! It causes a lot of extra work and you lose more of the teak than necessary that way. Remove the old caulking. Plenty instructions on the internet for it - spending on the special angled tool to scrape it out is worthwhile if you're doing the whole deck. Then recaulk, flattening the caulk with a putty knife (yes, smearing it all over the teak). After it's well and truly cured (a week at least,  probably longer depending on temperature and humidity - see data sheets), you can then sand the deck until all the smeared caulking is gone, which means you have also smooth, nice teak left now. This way you only have to mask the edges of the teak, not every seam.

Use TDS-SIS 440 or any other MS polymer based deck caulking. Would advise against Sikaflex 290DC, as it requires primer and uses outdated PU chemistry, which costs more and gives worse results (poor UV resistance).

That's another way of doing it, but it doesn't sound as if the OP's deck caulking is failing everywhere.  A patching solution, as I suggested, may be more appropriate.  As for Sikaflex 290DC, this is chosen by professionals throughout the world for its qualities.

[Symphony]

Agree with tiger79 about using Sikaflex290DC, or alternatively Sabadeck which is a bit cheaper. I used Saba on a teak deck I laid a few years ago and it was both easy to use and has lasted well. Also agree with masking either side of the seam and removing the tape immediately. I remember to cardboard boxes, and the caulking covered tape having minds of their own so best done on a windless day in short lengths remembering the brick in the box.

Lot of work involved and like your rigging question, maybe just clean the teak with a light sanding and let the buyer decide what to do with the caulking. It is the sort of job that is really only worth doing if you intend keeping the boat to benefit from the work.

[Spirit of Mary]

I did the reseaming approx 7 years ago. Already after 7 years the old Sikaflex seams started to detoriate. My Bavaria is year 2003. So my opinion is that Sikaflex is not sufficient UV resistant. I used TDS SIS-440. This is perfect after now 7 years. It has the advantage that the mechanical properties are much better than Sikaflex and tape at the bottom of the groove is not required as well as the primer for preparing the grooves.
It is a lot of work. I needed 1 full week with 2 persons.
To remove the old caulk I used the special Fein U shape tools on my multitool. You can get adapters for your specific multitool brand. I recommend to tape the sides of the seams. By doing this you need much less sanding, saving a lot of the thin Bavaria teak. Be sure that all the old caulk is removed, so the sides of the grooves need also carefull sanding. After caulking flatten the caulk with a putty knife pulling the knife under an angle of approx 45 degr. after the knife the caulk comes slightly up above the tape. After removing the tape and hardening of the caulk you have sufficient extra caulk for sanding flat with the teak.

To my opinion patching is a timely solution because Sikaflex is used and next patches will follow soon.

[tckearney]

Thanks Guys I'll work out a way of starting this, its a bit dificult in Scotland 'coz of the rain so may sail it sout to so it.

[Symphony]

Suggest wherever you do it you treat yourself to a pair of knee pads! Also essential when laying patio decking or block paving. Done all three just to prove that they are all jobs you should pay somebody to do if you can!