3M 5200?

I keep seeing that people mention to put 3M 5200 on rivets and bolts on the aluminum boats. Well I have been doing that without really questioning it but was looking at the product packaging and it doesn't mention that it is meant for aluminum. It was for wood and something else. So why are we putting 5200 on? Does it actually help seal it or is it something that people have heard and just do?

I find it hard to believe that you've actually used it before and have to ask that question. Yes it seals and it seals very well. After having my transom welding done, I discovered I had a slight leak. After inspection, I found what looked like a small air pocket in the weld that was allowing water to seep through. I took a very small drill bit and drilled the air pocket all the way through. I squeezed some 5200 into the hole until it came out the other side of the 1/8" aluminum. That was last spring and it still holds great.

I asked because I have never seen the results of it. I used it 2 days ago for the first time and was reading the package which is what brought this question to mind. I reckon I will see the "results" when I put the boat in the water which seems like it will be forever since my build is progressing so slow!

Not sure about it's sealing properties , but I put the aluminum flooring on top of the aluminum ribs 15 years ago useing 5200 . I need to take it up to run some wires 3 weeks ago . I had hell getting it up . I thought i was going to bend the flooring.

3M 5200 is flexible which is why it works well. It holds up to vibrations and chop which eventually can even bust up JB Weld. I believe it also helps with buffering the stainless steel + aluminum connection which protects the hull a bit more from corrosion.

Do you trust it enough to rivet something directly to your hull below the waterline?

Jeff, I would say yes these guys do as most of the rivets people are replacing and filling with this stuff is below the water line. In all reality, the closed/solid rivet should do all the water sealing for you. I think the 3M 5200 is more for piece of mind than anything. I know the 100's of stock rivets on my boat didn't have any 3M 5200 on them.

I trust it enough that I put it on the 6 stainless bolts that hold the transom knee brace to the bottom of my boat. These are bolts, (not rivets) that are are underwater 100% of the time my boat is in the water.

NLaudy said:

Jeff, I would say yes these guys do as most of the rivets people are replacing and filling with this stuff is below the water line. In all reality, the closed/solid rivet should do all the water sealing for you. I think the 3M 5200 is more for piece of mind than anything. I know the 100's of stock rivets on my boat didn't have any 3M 5200 on them.

Click to expand...

Is that the same as a blind button rivet?

Edit post:
Could I use 3/16" aluminum rivet/aluminum mandrel blind rivets for most applications?

What kind of rivets are you guys using?

I used 5200 all over my boat when I referbed it. No issues so far. I've used it on my jet skis as well with good results. My father in law swears by it and has used it for years. I trust his opinion as he grew up on boats and has a lot of boating experience. Below is a pic of my transom during replacement.

Jeffrey said:

NLaudy said:

Jeff, I would say yes these guys do as most of the rivets people are replacing and filling with this stuff is below the water line. In all reality, the closed/solid rivet should do all the water sealing for you. I think the 3M 5200 is more for piece of mind than anything. I know the 100's of stock rivets on my boat didn't have any 3M 5200 on them.

Click to expand...

Is that the same as a blind button rivet?

Edit post:
Could I use 3/16" aluminum rivet/aluminum mandrel blind rivets for most applications?

What kind of rivets are you guys using?

Click to expand...

I used 3/16" aluminum rivet/aluminum mandrel closed end blind rivets then just put 5200 on it.

NLaudy said:

Jeffrey said:

NLaudy said:

Jeff, I would say yes these guys do as most of the rivets people are replacing and filling with this stuff is below the water line. In all reality, the closed/solid rivet should do all the water sealing for you. I think the 3M 5200 is more for piece of mind than anything. I know the 100's of stock rivets on my boat didn't have any 3M 5200 on them.

Click to expand...

Is that the same as a blind button rivet?

Edit post:
Could I use 3/16" aluminum rivet/aluminum mandrel blind rivets for most applications?

What kind of rivets are you guys using?

Click to expand...

I used 3/16" aluminum rivet/aluminum mandrel closed end blind rivets then just put 5200 on it.

Click to expand...

Maybe you could put the 5200 on the rivet before you set the rivet so that there would be a film of 5200 between the deformed part of the rivet and the metal that you joined?

That is what I did. Sorry didn't make myself very clear.

NLaudy said:

Jeff, I would say yes these guys do as most of the rivets people are replacing and filling with this stuff is below the water line. In all reality, the closed/solid rivet should do all the water sealing for you. I think the 3M 5200 is more for piece of mind than anything. I know the 100's of stock rivets on my boat didn't have any 3M 5200 on them.

Click to expand...

X2 on this!

Properly installed rivets are perfectly water tight.

In an ideal world, any leaks would be fixed by replacing rivets or welding cracks ..... but since we don't live in an ideal world, 5200 is there to bail us out, and it does a darn good job of it.

MrSimon said:

In an ideal world, any leaks would be fixed by replacing rivets or welding cracks ..... but since we don't live in an ideal world, 5200 is there to bail us out, and it does a darn good job of it.

Click to expand...

:LOL2: I think we use it to prevent us from bailing out! :LOL2: