Cockpit recaulking - how to deal with edge seam near gelcoat?

[mibbal]

Hello Mates,

I'm preparing for complete recaulking of my teak cockpit with TDS SIS440.

Any experience based advise on how to do seam at the edge, between last teak plank and gelcoat (as shown on attached picture)?

I understand how to deal with seams between planks, but this one on edge is a bit tricky for me since is would not be possible to sand it.
Should I use finger or special putty knife (for bathroom silicone) to form the seam?
Can I remove SIS440  (when not cured) from gelcoat with acetone?

[Yngmar]

Masking tape and finger if you want a concave seam, or a wooden stick if you want straight. White spirit should be sufficient, acetone probably not ideal. Have a big bucket/cardboard box with bin liner and brick in the bottom to toss in the masking tape without dripping everywhere.

Then don't step into it. Good luck!

[Ailatan]

Acetone also worked for me.
Take into account that TDS SIS440 shrink a lot so even if you use a straight tool you will finish with a concave shape

[Odysseus]

I agree white spirit is good for cleaning, not as aggressive as acetone. However i used CTI sealent, i find it does not melt in hot sum.

Odysseus
Bav38

[mibbal]

Thanks Folks for the advises!

Should I sand after removing old caulking (before applying new one)? In some sources it is recommended to do so, but I'm not sure why. I guess sanding before application of new caulking may help to make surface smooth. Any suggestions?

[marioxp]

I would not advise you to sand before caulking. Because you will definitely have to sand after caulking.
I masked everything with tape, after I applied the caulk, I leveled the caulk with a credit card.  Immediately, while it was still fresh, I removed the masking tape.  I am very satisfied with the result.  I used a Sika 290DC.
I just had to sand a little.

[Ailatan]

I sanded the seams before applying TDS for two reasons: first because TDS is completely different product than the old one and second because I changed the original black colour for white.

[N44rag]

Is it best to fill the gaps between the teak first and let that cure before doing the perimeter seal later, or better done in one go?

Martin

[Happysailor]

I used the masking tape as suggested as well and it depends how clean you can work. Last time I did it in 1 go, masking the seams and trimming the tape exactly to the shapes with a Stanley knife. It also can be done in 2 steps. The compound is still fresh and will easily connect in the 2-step seem.

[mibbal]

Folks, thank you for all suggestions!

Finally I came to Greece and started the work, but after removing old caulk I found that seams don't go up to gelcoat... (please see attached picture). I expected to to see teak planks glued to gelcoat and gaps between them (up to gelcoat). But instead it looks like teak sections are solid areas of teak wood with grooves just for decoration. Is it the case?

If this is the case, I think bond breaker tape is not required, right?

[tiger79]

But instead it looks like teak sections are solid areas of teak wood with grooves just for decoration. Is it the case?

I don't think so, if you look at the grain it shows these are individual planks with a rebate cut on one edge to form the groove.

[mibbal]

But instead it looks like teak sections are solid areas of teak wood with grooves just for decoration. Is it the case?

I don't think so, if you look at the grain it shows these are individual planks with a rebate cut on one edge to form the groove.

Not sure I got it... It looks like old caulking is siting in the bottom edges of the groove. I even started to deeper the grove with my fein tool since it was only 3mm depth, and it was hard to remove old caulk from bottom edge. If this is rebate cut, then is it save to deeper the grove?

 

[mibbal]

But instead it looks like teak sections are solid areas of teak wood with grooves just for decoration. Is it the case?

I don't think so, if you look at the grain it shows these are individual planks with a rebate cut on one edge to form the groove.

Not sure I got it... It looks like old caulking is siting in the bottom edges of the groove. I even started to deeper the grove with my fein tool since it was only 3mm depth, and it was hard to remove old caulk from bottom edge. If this is rebate cut, then is it save to deeper the grove?

Ok, now I got it. I guess you mean rebate looks like on attached picture. In this case there is nothing wrong with making groove more deep, because this basically remove (or cuts) the rebate, which actually increase effective teak thickness ( anyway, rebate is not required any more)

Correct?

[symphony2]

Think you will find the strips are glued onto a ply base - they were on my 37 of the same year. so no need for a breaker tape, just fill the seams with caulk and level.

[Yngmar]

I removed the teak deck (thread about it with pictures somewhere nearby) and it wasn't rebate or routed, it was individual planks, but because they're prefab, they are glued onto two think layers of teak ply. When recaulking (a few years before removing it) I didn't use any bond breaker and the parts I had recaulked were fine even in extreme heat (unlike the original caulk, which melted, heh).

[marioxp]

Folks, thank you for all suggestions!

Finally I came to Greece and started the work, but after removing old caulk I found that seams don't go up to gelcoat... (please see attached picture). I expected to to see teak planks glued to gelcoat and gaps between them (up to gelcoat). But instead it looks like teak sections are solid areas of teak wood with grooves just for decoration. Is it the case?

If this is the case, I think bond breaker tape is not required, right?

It's the same as mine.  One large plate of teak wood and the grooves are only aesthetic.  I removed the old caulk with a chisel and cleaned the grooves with sandpaper.  I did not use bond breaker tape.  I masked everything except the gaps with masking tape.  As I used the sika 290DC I put an primer.  I filled the gaps with caulk, lined it up with a credit card and removed the masking tape while it was fresh.  So I had to do minimal sanding.  it's been a year now and I'm satisfied with what I got.  And the procedure is quite easy.  I had an additional problem that the teak panel separated from the gelcoat, so I cut a hole in the teak with an angle grinder, removed part of the old adhesive and filled in epoxy glue.  It holds for now.

[mibbal]

Thanks folks!

Work in progress... Indeed, there is a plywood or thin teak plate under the planks.

Any ideas how to remove old and very sticky caulk on edge seam (between last plank and gelcoat, picture attached)?

Is it safe for gelcoat to use acetone?

[marioxp]

It is safe to use acetone on gelcoat.

As I know.

[Yngmar]

For caulking that has melted (gone sticky), I used cleaning alcohol which you could buy by the liter bottle in most Mediterranean supermarkets. Acetone works but alcohol worked better and I had lots of sticky goo to clean. Also it's not as aggressive when cleaning it off your feet

[mibbal]

Thanks, Yngmar! I found something called alcoholic lotion (70°). Will try. I also have a little of 96% alcohol.

[Ailatan]

I used acetone and a Chinese food sticks working on the old caulking like if it was an eraser

[mibbal]

I would like to thanks everyone who replied! With your help I was finally able to finish this job.

Thanks, folks, for your help!

I found it very handy to clean the edges of the groves with sanding finger for osculating tool:
https://www.bosch-professional.com/nl/nl/expert-avz-32-rt10-sanding-fingers-2867214-ocs-ac

[Smeaks]

My seat teak is lifting can you buy replacement sections to replace with adhesive ?