Deck sealant

[Ian_Edwards]

I've just started removing the sealant (caulking) between the teak deck and the GRP bulwalk, which is gelcoated.
The sealant has failed at the inter face with the gelcoat.
I'm using a Fein caulking removal tool, and plan to use a TC abrasive tool to clear the bottom of the grove and the add some epoxy thickened with micro fibers to seal the bottom of the Grove.
With luck the caulking will be cosmetic, but I'd like to ensure a good bond to the gelcoat and the edge of the teak deck plank.
The caulking will be black.
CT1, OB1 Sikaflex or what?
I've used CT1 extensively and it's a great glue, but not that UV resistant.
Not had that much success with Sikaflex.
I've never used OB1.

 

[Ammonite]

Caulk

 

[Ian_Edwards]

Thanks Ammonite, I'll look.at that this evening.
Update: I started removing the old caulking this morning, using a Fien multitool.


Although it not very clear in the photo, when I remove the old caulking, I'm left with a slot 6mm wide and at least 15mm deep, possibly 20mm. I can see the gelcoat of the deck flange at the bottom of the slot.
There also appears to be void under the edge to the teak plank.
I still need to abraded the bottom of the slot.
I'm still considering pouring some low viscosity epoxy resin, with some micro fibres added, then finishing with black caulking.
Using the Fien Multitool is very much faster than using a mortise chisel. I did about 1.5m in 90min, and a lot of that was finding out how not to do it!

 

[Ian_Edwards]

Update, I've cleared about 3/4 of the caulking.
Very slow going, limited by my back, and the variable width and depth of the seams, anything from 3 to 6mm wide and 8 to 15mm+ deep.
There were also "holidays" in the caulking. They look like the end of one tube of caulking hasn’t quite meet up with next.
When I've cut the caulking out, there's a layer of soft resin like material between the teak and the underling gell coat. It almost looks like under cured resin of some sort. It's brown, very soft and the caulking tool cut through it easily.
Any ideas what it might be?
I've also noticed this crack in the planking, next to one of the very few screw fastening. I'm fairly sure that this is the cause of one of the leaks.
How would you repair this?
My initial thought are to cut the split section of planking out a replace it. I'd bed it in thickened epoxy, so it wouldn't need a screw.
Comments?

 

[Tranona]

Not sure about using any epoxy to fill voids or to stick new teak down. Keep it flexible. You don't say how thick the teak is where the repair is needed. The screw is probably now redundant, if it is there at all. I would be tempted to remove the plug and possibly rout out a 6mm wide slot for a spline rather than remove a section. Once it is in place then redrill for a new plug. Once it is weathered in you will hardly notice it.

 

[pyrojames]

Avoid epoxy, the caulk doesn't like sticking to it. Clean the seems with acetone before putting the caulk in. Follow the TDS instructions carefully. Just done my 50 old footer.

 

[rogerthebodger]

My understanding is to lay tape at the bottom of the groove to prevent the sealant from sticking to the bottom of the groove this will allow the c corking to expand uniformly and not break away from the sides of the wood strips

 

[Ian_Edwards]

Thanks for the input.
I can't rout a grove and insert a small section of teak, the crack is too close to the cabin side. There's not enough room to land the router. But I could mark out a section to be replace and then us a fostner drill bit to take most of the waste away, finishing with a sharp bevel chisel.
Would I be better to fit a spline with caulking or Gorila glue?
Thanks for the info' on the lack of adhesion between expoxy and caulking, I wasn't aware of that.
The caulking I'm taking out stuck very well to the teak. It hasn't adhered well to the gelcoat on the bulwark. As I'm removing the caulking I can see grey silt in the cracks between the gelcoat and the caulking where its been leaking. I plan to abrade the gelcoat before I re-caulk, to get a better bond.
I'm not sure about the tape in the bottom of the grove. It would be hard to do, because the width of the grove varies so much. And, as I understand it, the teak was vacuum bonded to the deck before the deck was mated with the hull, so the expansion and contraction of the teak deck is likely to be limited?

 

[Tradewinds]

I would use a fein saw blade and chop out the teak section neatly right angled up to where the split starts. Remove the screw . Clean the grp underneath using a chisel/scraper. Fill the screw hole. Clean the caulk groove with 36 grit glued to a thin piece of batten. Acetone copiously them insert a suitable piece of teak bedded down on G Flex epoxy (thickened more if necessary). Butt up against the old teak using standard G-Flex. Caulk with TDS (preferably) or whatever the chandlery stocks. You don't need bond breaker tape for such a small section IMO. Sand the deck so it's fair. In 5 years you won't notice that it's been repaired there .

 

[Ian_Edwards]

Thanks for the advice.
Looking at the screw hole/plug again this morning. It occurred to me that the only place the water can get below is through the screw hole. The rest of the deck is solid GRP.
If I can remove the plug and get the screw out. I could fill the hole with thickened epoxy and replace the plug with an over sized plug.
The teak deck is thin, 6mm originally, probably about 5mm now after 17 years or so.
Would that work?
I would be left with a short length of split plank, but that shouldn't cause a leak in the short term.
I intend to replace the teak deck, I'd planned to do it this winter, but an unexpected problem with the roof of my house has mopped that bit of spare cash.

 

[geem]

I've just started removing the sealant (caulking) between the teak deck and the GRP bulwalk, which is gelcoated.
The sealant has failed at the inter face with the gelcoat.
I'm using a Fein caulking removal tool, and plan to use a TC abrasive tool to clear the bottom of the grove and the add some epoxy thickened with micro fibers to seal the bottom of the Grove.
With luck the caulking will be cosmetic, but I'd like to ensure a good bond to the gelcoat and the edge of the teak deck plank.
The caulking will be black.
CT1, OB1 Sikaflex or what?
I've used CT1 extensively and it's a great glue, but not that UV resistant.
Not had that much success with Sikaflex.
I've never used OB1.

TDS caulking just the same as you use in the teak deck. SIS440