Working with 3M 5200

I just removed the leaking hatch cover rims from one of my boats and replaced them using 3M 5200 marine sealant. I was surprised at how fluid the material was and how much it ran out the joint between the rims and the boat. I was expecting a caulk-like consistency. Fortunately, I had everything well masked and will have to do a lot of trimming when the stuff cures, but I am wide open to tips and tricks that other paddlers use in using this stuff. Thanks mucho in advance-----------

Doesn’t sound right
Every tube I’ve ever used has been thick and gooey, like honey that’s been in the fridge.


I used it to seal the stitched seams when I built my SOF. I got essentially very little flow from it at all. In fact I found it hard to work. The only way I could get it to flow was a lot of heat - like outside when it was over 90 degrees F. It worked well, but did take a good 7 days to cure.


something wrong there… 5200 is definitely NOT runny unless it is very warm. Once it sets, it considered a permanent adhesive. They actually glue some high end yachts together with this stuff. The decks are glued to the hulls, no bolts or screws, just 5200…

4200 is not runny.
I’ve got a tube of 4200 that I used in a caulk gun - it was NOT runny at all. Can’t imagine the 5200 is, either.

No Bolts? Not Hardly!

Actually, all large boats use 5200 for the hull to deck joint, yachts over 25ft are thru-bolted, too. 5200 is certainly strong, but not strong enough to keep a deck permanently attached to the hull.

bad product?
The tube was not heated up, but was one of those capped squeeze tubes that come in a package. Is there a chance that perhaps it was old or something? I’m a builder and have used caulks of all sorts all my life, and this one was surprising to me. Cheers------------

don’t know this but …

– Last Updated: Dec-22-10 6:02 AM EST –

...... perhaps because of what you just said "it was one of those capped squeeze tubes" ... that may be a reason for it's thinner viscosity than standard caulking gun tubes .

Just a thought that it has been mfg./formulated that way purposely to facilitate ease of application for hand squeezing from a small tube . Seems they could do that by adding more thinning agent (VOC) w/o harming product . Is there an 800 # to contact mfg. and inquire about viscosity thickness concern you have ??

Anyway , how has the hatch seal turned out ... seem to set up ok by now ??

I had the same problem…
I had used the small tube as well, with same results. Don’t know who I heard it from, but put the tube in the freezer for about a half hour prior to use. I tried it, and it works a whole lot better. Much thicker and easier to work with. Good luck.