Sealers and Caulks

[Mark42]

Thought it would be good to have a discussion on the popular sealants and caulks. I have used 3m and Boalife products, so i'll write about those.

1) 3M 5200 - Polyurethane sealer. Strong seal. Might as well epoxy the parts together. I have had a heck of a time getting things apart that someone used 5200 to put together.

2) 3M 4200 - Polyurethane sealer. Good seal, stays soft. Works well and the parts do come apart fairly easily. Cleans up easily from most surfaces. Good for bedding deck hardware.

3) Boatlife Life Seal - Polyurethane/Silicone sealer. Good seal, stays softer than 3M 4200, much more stretchy. Probably because of the marine grade silicone in the mix. Clear. Comes off most surfaces clean with a little work. Good for bedding deck hardware.

4) Boatlife Calk - Polysulfide sealant - Stays soft, sandable and paintable. A good marine grade calk.

I believe all of these products can be applied above and below the water line. They all will cure below water.

My favorite is the Boalife Life Seal because it has a more elastic quality than the 4200 and its clear, so it doesn't show if its visible. So far I haven't had any of these products fail, but the 5200 is something I don't buy anymore because I can't think of a application where the 4200 or Life Seal won't do just as well.

 

[BigJ08]

Re: Sealers and Caulks

I think that 4200 and the boatlife products are fine for deck hardware as you mentioned. But I think 5200 is absolutely necessary for thru-hull fittings like drain tubes etc. , wouldn't trust anything else.

 

[Bob_VT]

Re: Sealers and Caulks

Great post Mark. The key is to notice they are not silicone sealants. We have seen too many people try to use silicone and it fails way to easy.

The key here is the right product for the right job

 

[Mark42]

Re: Sealers and Caulks

There is a lot of great info on this forum and it's really great that people share their experiences with various products. I also reccomend going to the manufacturers websites and read about the products. I got some great tips on how to use one of the sealers. Manufacturer says to speed up cure time, to WET the product. Would never had thought of it.

I think its also important to see what other products the manufacturers make, because you may find that there is another product that works better than the good old "stand by". People get in the habbit of using what they have on hand rather than take the time to check if its the right product for the application.

I remember about 5 years ago everyone used 3M 5200 to bed down everything. Then a few years later people found they could not get their outboards off the transom! Lesson learned the hard way, but now you will rarely read of anyone using 5200 on anything that has to come apart for maint or service.

Gosh, I love these forums!

 

[Mark42]

Re: Sealers and Caulks

I think that 4200 and the boatlife products are fine for deck hardware as you mentioned. But I think 5200 is absolutely necessary for thru-hull fittings like drain tubes etc. , wouldn't trust anything else.

Yep, I agree that is a good application for 5200. Ok, so maybe I will pick up a little tube of 5200.

 

[Matrex]

Re: Sealers and Caulks

So, can I read into this that 5200 is the right stuff for plugging the holes I made through the hull when clamping in my new transom? I was thinkig to fill in the holes, and sand them smooth and touch up the paint. That is my next strp when we melt down....

 

[Mark42]

Re: Sealers and Caulks

So, can I read into this that 5200 is the right stuff for plugging the holes I made through the hull when clamping in my new transom? I was thinkig to fill in the holes, and sand them smooth and touch up the paint. That is my next strp when we melt down....

Depending on the size of the holes.... Screw holes would probably be fine. I would use marine tex epoxy. Anything bigger than 1/4" or so and you really should use epoxy so there is no issue with shrinkage and leaking.

 

[Moody Blue]

Re: Sealers and Caulks

I'll add my 2cents here. Good topic and will be interested in others experiences.

Beware that 3M 5200 is not the be all and end all of sealants. I have had less than satisfactory results in a couple instances when used on stainless steel or aluminum materials. 3M's tech info supports this fact. Granted, it sticks like crazy to fiberglass, wood, plastics etc., and have actually delaminated gel coat from the fiberglass after trying to remove a transducer from the transom. Have not used the 4200 product so can't comment on that.

Can't recall right now what the last product I used was but was very happy with its performance. Will dig around the shop and see if I can find it. I think it was something like Sikaflex but not sure.

What is the issue with silicone? The previous owner of the boat I am refurbishing used it everywhere and I can tell you I had a he!! of a time getting it off. I have used exterior grade silicone for various projects outside the house and again it sticks like crazy and seems to last forever.