Alternatively titled 5200 operator error. While I’d much rather post about something fun and lighthearted I feel it’s important to share our recent story about the hull to deck joint. If you remember back in the spring we removed the caprails and caulked the joint with 5200. Well last week when I removed the curved caprail at the bow of the boat I inspected that new caulk seam only to find something “terrifying”, the caulk didn’t bond at all on 3 sides in the seam of the hull to deck joint.  Once I got a good grip the caulk just pulled right up. Now I don’t know if this was a true 5200 caulk failure but this level of adhesion didn’t sit well with me. At all.
Screwdriver under caulk

I’m pretty sure 5200 isn’t supposed to come up this easy.
Pulling up the old caulk

The caulk was adhered kind of well to the tops of the joint and upper outer hull, but not in the seam at all. No it wasn’t leaking, at least not yet. All week I mulled over (agonizingly) what to do. Should I leave it and hope for the best? UGH should I really just remove it all and start over? It wasn’t an easy decision as I spent alot of time doing this the first go around, but my better self got, well, the better of me. With leaks being one of the most dreaded thing on our boat (to me) I couldn’t leave it as is and since this was the most perfect time with caprails off still, I decided to remove it and start over.

Why did this happen? I went over and over my preparation for the hull to deck seam and realized that I didn’t even wash it soap water or sand in the seam at all, tragic I know. I remember scraping it with a screwdriver a ton and also rubbing it with acetone but obviously the seam was still very dirty. Just look at the dirt stuck to the caulk as I easily removed it. There was even dirt still in the seam.
Dirty caulk pieces

UGH, how could I have done such a thing, I’m usually so careful? I remember believing 5200 would stick to almost anything and figured the scraping and cleaning with acetone would be enough and also keep water out of the boat from a good scrubbing. Tate wasn’t around for this prep and trusted that I had done the right thing. Can you tell I’m new at this whole “boat refit” thing? But whatever, this time I wasn’t taking any shortcuts. Oh no, this time the 5200 was going to stick. This was so important to me I took off my half a day last Friday and worked 11 hours from about dawn until dusk to prepare the seam.

I got to it and tried various methods for removal,
Dani pulling up the caulk

even making a game of it to see how long a continuous run of caulk I could pull up. (this is about 7 feet)
Starboard caulk removal

Now it wasn’t all a piece of cake as the run above took me 15 minutes but a 2 foot section that Tate had prepared took me 2.5 hours to remove. I didn’t know just how stuck the caulk was in which areas so I thought it best to remove everything and start anew.

When all the old caulk was out I washed everything with a scrub brush and soap and water, which turned dark from the dirt still in the seam. Then I used a wire brush for the seam and gelcoat and a screwdriver with a towel for the screw holes (which were incredibly dirty) and rinsed again with soap and water.
Cleaning with a wire brush
Cleaning the screw holes

After the seam had dried I used the two towel method with Interlux’s 202 Fiberglass solvent wash (things got serious) that is supposed to help release grease, oil, mold release wax residue and other impurities from the porous fiberglass. I also read that sanding dirty fiberglass pushes the impurities deeper into the fibers, which is no bueno so you need to clean the fiberglass first before sanding.

Finally I sanded the seam and gelcoat with 60 grit aluminum oxide paper on the advice of Robert from Building a Westsail 42. Apparently fiberglass can be too hard for your run of the mill sandpapers and actually take the grit off the paper first.
Sandpaper in joint

Tate came with me today armed with five more tubes of 5200 to redo the seam and also caulk the area under the port side genoa track. I taped the exterior edge only and spread the caulk into the seam as he used a caulk gun. I occasionally dipped my 2″ putty knife in mineral spirits to help smooth and spread the caulk.

This went off without a hitch except that the half broken, bent and falling apart caulk gun almost killed Tate’s hand and Tate himself almost died from heat exhaustion (not kidding) in the near 100 degree heat index after a lengthy sailboat race with little water earlier. It was actually kind of a fiasco towards the end, but I did manage to get a nice seam.
Seam from far away
Seam caulked 02
Seam caulked
Seam caulked close up

This time we didn’t smooth the caulk all the way over the gelcoat on the inside edge in order to allow more direct adhesion when we reattach the caprails forward of the genoa track…with 5200. That’s right, we’ve pretty much decided to hell with screw holes through the joint we are going to straight glue the caprails down with 5200. You can call us screw shy if you wish, but really, it’s hard to imagine putting holes back in what we just closed up. There is nothing structural about the caprails forward of the genoa track and now that the hull to deck joint was properly prepped for caulk I think we’ll give it a go. In about two weeks I’ll go and check this joint out to see if it has properly adhered, I have high hopes!

I’m actually really glad we found this when we did and it turned into a blessing in disguise since from the outside the seam looked great. I searched quite a bit online for examples of 5200 caulk failure, or 5200 caulk that didn’t stick etc but came up pretty empty handed mainly reading discussions on the love hate relationship to the caulk (mostly hate), so I hope this is helpful to those other poor souls out there whose caulk didn’t stick.

For those few people interested in the elasticity/flexibility of 5200, I took these two photos to show how far *I* could pull it. Granted I’m not very strong, I found the 5200 to stay very flexible and springy after 6 months in the Louisiana sun through the summer and in no way brittle. I was able to stretch a piece from 12 inches to 13 inches.
12 inches
13 inches