Topic: How long do you have to let 3M 5200 cure before you can put your boat in

[C. Corner]

water? I plan on mounting a piece of king starboard to the back of my bass boat and was going to use the 5200 to seal the screw holes. One more question, why does several places recommend putting silicon on the screws while most on here are against it? I just don't want to be without my boat for an extended period of time since I hear  that it can take the 5200 several weeks to fully cure. Thanks in advance!

[LocDown]

Depends on which compound you pick. I believe there are two depending how fast you want it to cure. Fast and regular.

[C. Corner]

I guess I need the faster version. I don't want wait weeks for the stuff to cure as some have stated.

[LocDown]

Fast cure takes 24hrs to fully cure while the regular takes 5-7 days to cure.

[ITGEEK]

If you're in a warm climate, the regular 5200 will cure pretty good in 2 days.
Any good waterproof sealant/calk will work for you.

But, 5200 is designed for boats, and is resistant to harsh marine
environments like salt water.

I'd take my time and do it right, and use the right stuff so you never have to worry
about it again.  Getting water into your transom is the last thing you ever want to do.

[sonar2000]

Putting silicone on threads is a precaution of bonding the threads to the threaded hole. That is so you can get the screws back out.
5200 cures and locks.
Chuck

[bigkahuna]

Boat yards only use 3M 5200 for permanent bonding, like bonding the deck of a boat to its hull.  They would never use it to seal any fittings above or below the waterline.  I don't even know why West Marine sells it to DIY'ers, it's just a headache waiting to happen.  3M 4200 is better but to be honest, for the little holes you'll be drilling, seal the core with epoxy and then use a good silicone sealant to seal the bolt holes.  That's how the better boat manufacturers and yards do it.

[ITGEEK]

I'm sorry, but I have to disagree with some of you guys.
Regular 5200 (white) is the only thing I've ever used to seal screws/holes in my boat.
I've had my boat since 2001, so I've been using it for at least 10 years.
5200 is a sealer/adhesive.

When I've changed my sonar, I've sealed the screws with 5200 on the console, so water
wouldn't get into the console wood.  When I screwed together parts for rod holders, I used
5200 to help hold them together.  Screws sealed with 5200 can be backed out later.

Although 5200 is reported to be permanent.  It can be removed.
It takes work and can be a real bitch, but it can be removed.  I'm talking from actual experience here, not something I read in a book.

It is designed for marine use.   Under the water sealings is what it is most famous for.
It's the perfect sealer/adhesive to use on transom holes/screws.
I wouldn't use anything else.

If you use something designed for a house (like calk), it may not be able to take the harsh
marine environment.  Why risk a rotted out transom/sunken boat with something that is
questionable.

If not painted, 5200 will get dirty, but it doesn't ever rot.
Use the best.
In my opinion, 5200 is the best.

[bigkahuna]

"I'm talking from actual experience here, not something I read in a book."

I'm not going to post my resume on a public forum, but let me be clear:  I have worked in the marine industry for nearly 40 years.  I speak from experience.  I've also had to fix what some DIY'er messed up.  Yes, 5200 will certainly seal your holes but it's not what 3M recommends for the job nor is it what boat yards and manufacturers use.  Sure, you can chisel the part off if you change your mind, but you'll be wasting time and risking damage to both the boat and the part.  If properly prepped and applied, silicone sealant will do the job.  I've used it on more jobs than I care to recall.

I'm done with this subject.  If the OP wants to discuss this with me privately I'll be happy to share my experience with him.

[ITGEEK]

This is my last word on this subject also.
This was copied from Westmarine's web site.

3M 5200 Polyurethane Adhesive/Sealant:
Provides exceptionally strong adhesion, yet stays flexible
after it cures.  May be used above or below the waterline.
Ideal for underwater thru-hull fittings, hull to deck joints,
portholes, and bonding wood to fiberglass.
Goes on smoothly, won't sag, and remains workable
for up to four hours.  Cures in 5-7 days with no shrinking.