Priming over Boat Life Life Caulk

[Alex Batson]

I am building my first boat (a 12 foot, Lapstrake, Catspaw Dinghy) and the Interlux Brightside Primer is not drying over the Boat Life Life Caulk. The primer is dry on the cedar planking, but not the Caulk. I finshed priming the boat Saturaday at 1 PM and it is now Monday at 9:21 AM and the primer is still not dry where it is covering the caulk. Boat Life says this caulk can be sanded and painted. The Caulk was dry and cured before I began priming. (The Caulk had ten damp days above 50 degree to cure). I followed the Application Instructions on the primer including wipping down the planks (and therefore the caulk) with Interlux Brushing Liquid 333.
Has anyone else had this experience? Is this young Jeddi not being patient enough? By any chance, does the kerosene in the Brushing Liquid interfer with the caulk's ability to accept paint?What should I do?

[Scott Rosen]

Did you pay your hull seams with boatlife?

[Gary Bergman]

I don't use interlux, but I paint over a ton of boat life any never have problems, just maybe need more time. I usually wait 2 weeks;although the paint went right over the bottom seams, and none is flaking.

[Scott Rosen]

Sounds as if he paid the topside seams with boatlife.

[Alex Batson]

I ran small bead of Life Caulk along the apex where two planks meet, on both the top sides and bottom sides. No caulk was placed between the planks.

[Scott Rosen]

Sorry. I should have read more carefully. It's lapstrake. I was thinking carvel.

[Alex Batson]

I contacted Interlux today regarding this problem. They claim that their primer will not dry over Life Caulk or any polysulfide caulk unless the calk is first wiped down with soapy water. Interlux asserts that the polysulfide compounds with prevent proper adhesion of their Brightside primer. They compare this situation to removing the amines from dried epoxy before painting over the expoxy.

[Alex Batson]

I contacted Interlux today regarding this problem. They claim that their primer will not dry over Life Caulk or any polysulfide caulk unless the calk is first wiped down with soapy water. Interlux asserts that the polysulfide compounds with prevent proper adhesion of their Brightside primer. They compare this situation to removing the amines from dried epoxy before painting over the epoxy.
I contacted Boat Life about this problem and they thought it was becuase the caulk did not fully cure. Boat Life claims Life Caulk will cure in 7 - 10 days only if the temperature is continusouly above 70 degrees and with high relatively humidty. With out these conditions, the caulk take an extra long time to cure or not cure at all. Boat life stated that Life caulk does not do will when applied in very dry or very cold climates.

[Alex Batson]

I contacted Interlux today regarding this problem. They claim that their primer will not dry over Life Caulk or any polysulfide caulk unless the calk is first wiped down with soapy water and then dried off. Interlux asserts that polysulfide compounds with prevent proper adhesion of their Brightside Primer. They compare this situation to removing the amines from dried epoxy before painting over the epoxy.
I contacted Boat Life about this problem and they thought it was because the caulk did not fully cure. Boat Life claims Life Caulk will cure in 7 - 10 days only if the temperature is continuously above 70 degrees and with high relatively humidity. With out these conditions, the caulk takes an extra long time to cure or does not cure at all. Boat Life stated that Life Caulk does not do well when applied in very dry or very cold climates. Boat Life also claims that the only way to correctly clean any residue off the Life Caulk is with either Acetone or Life Caulk Solvent and Cleaner. Soapy water will not do anything. Regarding one of my original concerns, that is Life Caulks compatibility with the Kerosene base Interlux Brushing Liquid, they said this should not be a problem as long as the Life Caulk is wiped down with Acetone or the Life Caulk’s Solvent and Cleaner afterwards. Boat Life claims the Kerosene is basically oil.
I know this is a long-winded statement, but I wanted to pass along the information I learned today in hopes of helping someone avoid my mistakes. I am also interested if anyone else wipes down the Polysulfide caulks with soapy water before painting over the caulk? This situation seems a bit unbelievable because both Interlux’s Brightside Primer and Boat Life’s Life Caulk are well known and seemingly well regarded products. It seems that this information would have been discussed on this web site before or printed in one the numerous goods books on boat building.

[thechemist]

Mercaptans are extraordinarily reactive. Those are the reactive chemical groups on polysulfide prepolymer molecules. Even if they were the problem, soapy water would not remove a molecule, one end of which is buried in the polymer and only the unreacted other-end sticking out. That's B. S.

I think Boatlife has 'way too much of a low-molecular-weight plasticizer that bleeds out and screws up adhesion. It *does* improve the profit margin, though.....they've been doing this for over 30 years.

TEST: Spread a film of Boatlife maybe 1/8" thick on a piece of polyethylene plastic such as a plastic bag. Let it dry and fully cure, for a week or whatever. Cut it in half and keep one wrapped in aluminum foil, inside a plastic bag, in the freezer, so nothing evaporates. That's your "control". Put the other "test" piece in the hot sun, and give it some months. You can accelerate this process by storage in a 200 Deg. F oven,[not the one you use for food] for a few days.

*Passage of time*

Let the warm one cool to room temp, the cold one warm up and then unwrap it, and compare flexibility. You will see shrinkage and feel a difference in flexibility. With a few years age in hot teak decks the stuff can get rather brittle.

On the other hand, maybe they changed the formula in the last few years. Try and see.

[Alex Batson]

Thank you to "thechemist". I always appreciate your scientific insights. Not being a chemist myself, could you clarify one thing for me? Since the Interlux Primer is not drying over the Life Caulk, is this an adhesion problem? It seems the problem I have is not one of adhesion but of curing (i.e. that is the primer curing.)
Something about this problem still seems unbelievable because both of these products are well known and have been around for several decades. This cannot be the first time the two products have been used together.
I checked the boat tonight (Wednesday) and the primer is still wet over the caulk. Acetone seems to remove the primer from the caulk, but it also removes the dried primer for the planks as well. I guess I have to start all over again. I just hope that this time, the primer dries over the caulk. Does anyone else have a suggestion or comment this problem?

[Scott Rosen]

Boatlife one-part polysulfide is a poor quality product. Chemist gave you the scientific reasons for that. I know from my own experience years ago that when I used it to patch some seam compound on my teak deck, the Boatlife didn't even last the season.

Here's my suggestion. Reef the Boatlife out of your topside seams and use something else. I like Interlux white seam compound, which is a linseed oil based product that stays soft and flexible for years. If you absolutely have to have a plastic goo in your seams, then try a low-adhesive polyurathane.

[Chippewa Greg]

What about the two part polysulfide from Boat Life for deck seams? I just ordered some for the seams in my launch.