Deck Caulking Virgin

fastjedi

fastjedi

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Sometime over the next 4 weeks I will be fitting 6x new pre made 6mm teak panels into an 9mm GRP recesses. Having done that, I will be caulking the 4mm gap between the teak and GRP .... all flush when complete.

I understand I would apply the caulking, allow to cure and and sand back if I was working between two teak planks. I am not so sure this is the right approach when working to a GRP edge?
- The GRP edge rolls into the recess / is not as consistant as the edge of a plank
- I doubt the top edge of the teak panel will be perfectly aligned with the GRP everywhere

I guess the alternative is to mask off the teak and GRP, apply the 290DC and then dress with a knife of similar to get the final finish.

Thoughts?
 
I have caulked teak but not to a raised edge as you describe, though I have carried out something similar when caulking acrylic windows in metal frames.
I would favour masking both surfaces very carefully, spend time positioning the tape accurately, use an old tea spoon or a rounded blunt knife as a caulking tool to get a slightly concave profile and do not over apply as you will get a mess when you smooth it. Make sure the sealant is finished to minimum thickness where it goes over the edge of the tape. Strip the tape early and have a big bucket or similar handy to put the mucky tape into as you remove it. When I did the windows this way the boat yard hand walking past stopped to congratulate me on the tidy finish, so I was well chuffed.
 
I take my hat off to you guys doing teak work and caulking.
I tried it as a stop gap measure to keep the water out of my deck on my Tradewind during May/June last year. On a rainy day I had 9 buckets collecting the drips at one time down below. I gave up being neat and tidy and the caulking was ouzed down between the planks and simply left unfinshed. It did the job during those very wet and windy months though and even in F7's with a choppy sea we didn't get water ingress.
I did consider re-teaking the deck ..... now that would have been a good Uni' project!.
The Tradewind has a very large foredeck and even if I did it myself it would have cost quite a few thousand. Without having a workshop alongside makes it's all the more difficult.
Instead I stripped all the teak off and epoxied and applied strand mat. Then Ben from bwseacat based at Wicormarine, added a flow coat of gel with non slip areas of resin with fine sand and shell grit.
It's really not as beautiful aesthetically as the teak but easier on the pocket and hopefully better as far as maintenance goes.
The difficulty of selling an older boat with a teak deck also prayed on my mind.
 
Go with the masking both edges method. When tooling the caulking to the concave finish use a tool with a clearly defined edge so that there is virtually no caulk on the edge of the tape - bit like sealing round a bath. Wear thin rubber gloves so that you can take the tape off quickly without it flailing everywhere - sometimes useful to use shorter lengths of tape. It is possible to trim with a knife when it is set, but not on the GRP. Might be worth doing a small mock up piece first to try out the techniques as you only get one shot at the real thing.
 
Tranona said:
Go with the masking both edges method. When tooling the caulking to the concave finish use a tool with a clearly defined edge so that there is virtually no caulk on the edge of the tape - bit like sealing round a bath. Wear thin rubber gloves so that you can take the tape off quickly without it flailing everywhere - sometimes useful to use shorter lengths of tape. It is possible to trim with a knife when it is set, but not on the GRP. Might be worth doing a small mock up piece first to try out the techniques as you only get one shot at the real thing.
Click to expand...

+1

Teaspoon is pretty good, though, for the rounding. Sanding teak isn't great - much of the oil that protects it is just below the surface. There is a slight tendency to sand it and then have to oil it to put the protection back.

FWIW, it *should* look silvery-grey. That's how weathered teak looks (and I like it like that). If you don't, you can oil it, but it shouldn't be necessary as long as you haven't sanded it...
 
Take it off straight away, otherwise not only are you likely to have problems with making a clean break at the edge of the caulking, but the masking tape will stick to the GRP and will be a devil to get off. Guess how I know!
 
fastjedi said:
Excellent ... Thanks for all your advice.

I may have to leave the masking tape in place until the following weekend though
Click to expand...

The idea of smoothing to nothing where it meets the tape is to allow the tap to come away from the soft sealant with a straight clean edge. What you are doing is almost identical to caulking around a shower tray which most people do from time to time. The same rules apply, too narrow a gap filled with sealant will not allow sufficient movement without parting, you want something like 5mm. So take it off wet, you will regret leaving it for a week even if you use the blue longer life tape.
A vacuum cleaner is good for getting dust out of joints which need to be very clean and with Sikaflex DC it is important to use the primer first.
 
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