West Marine Multi Caulk

[jason1903]

I am preparing to seal up my cockpit (fiberglass and teak) with Multi Caulk, but cannot seem to find much information on how to use it. I have a few questions in particular, hopefully someone here can answer them.

How deep of a bead will cure properly? There are some areas in corners which will require a considerable amount (1/2-3/4"). Would I be best off stacking several thinner applications?

It says skins in 1hr, cures in 2 days. It is currently the rainy season here in Florida, can it get wet before full cure?

The fiberglass portion of the cockpit is fairly new, about a year old. Do I need to scuff or dewax it?

The directions say teak primer is generally not needed except new applications. The only new portions are some strips 1/4" think, lying atop a seam between fiberglass and old teak, as in the attatched image. These strips have been applied with 5200. Multi Caulk will be used to bead between the strip and other areas, black at the teak/teak seam, white at the teak/fiberglass seam. Does this small bit require priming? There are also some v-grooves in some other areas where I removed the old caulk and sanded them a bit. Should these be primed?

Sorry if these are stupid questions, I just want to make sure I do it right as I am sick of having a leaky cockpit.

[roverhi]

Really need to know what this caulk's chemical heritage is. Polyurethanes (5200, etc.) and Polysulfides (Lifecaulk) actually require moisture that they normally pull out of the air to cure. They will cure completely submerged if you need to do an underwater repair.

The reference to skinning over puts up a big warning sign to me. Is this stuff sillycone based??? If it is, I'd run away as fast and far as possible from the stuff.

[McGinnis]

What's your reasoning for using the Multi Caulk?

You're better off laying smaller strips instead of one fat glob.

Not sure with the Multi Caulk if the rain is going to affect the curing, shouldn't be too much of an issue after a couple hours though. The 3M brand 4000UV is also a polyether caulking but it cures in 24hours. Might be something worth looking into, it also doesn't require priming.

[jason1903]

It is a polyether. That is a big part of my confusion, I can find info on the "big three", but not polyether.

[McGinnis]

Originally Posted by roverhi

Really need to know what this caulk's chemical heritage is. Polyurethanes (5200, etc.) and Polysulfides (Lifecaulk) actually require moisture that they normally pull out of the air to cure. They will cure completely submerged if you need to do an underwater repair.

The reference to skinning over puts up a big warning sign to me. Is this stuff sillycone based??? If it is, I'd run away as fast and far as possible from the stuff.

It's a polyether sealant, similar to the 3M 4000uv. It's not silicone based. A "skin" generally refers to a caulking in it's "tack-free" stage.

[jason1903]

Originally Posted by McGinnis

What's your reasoning for using the Multi Caulk?

You're better off laying smaller strips instead of one fat glob.

Not sure with the Multi Caulk if the rain is going to affect the curing, shouldn't be too much of an issue after a couple hours though. The 3M brand 4000UV is also a polyether caulking but it cures in 24hours. Might be something worth looking into, it also doesn't require priming.

I chose it because it is supposed to be good for teak seams, as I mentioned part of the project involved filling old v-grooves. It rated best for wood application in the West Marine catalogue (of course they just might be trying to sell their own product).

You mentioning 4000 brings up another question. This stuff says clean up with MEK, but 4000 says mineral spirits. Would they be interchangeable?