caulk?sealant

I like to use "Life Caulk" on the transom cap and engine bolt sealing. It is an area that one must work on occasionally and 3M 5200 is just too ornery to remove.

There are two types of spashwell drain tubes that I am familiar with. The best is bronze tubing which has one end rolled and then you use a hand tool to roll the other end after it is pushed through a well sealed hole. I have not been able to find bronze since my wood boat period but brass is available and satisfactory above the water. The second type I have used is a two piece item. I have seen them in both brass and nylon. One slides inside the other so you just seal up the hole and slide the larger of the two in from outside the transom and slide its mate into it from inside the splashwell. Making sure that Mr. Life Caulk is present in all the correct areas..

As mentioned, Lifecaulk is fine but as long as the area is not below the water line, regular silicon caulk will work (and is less expensive and easy to find). Use the kitchen/bathroom variety as it has a mildecide (?) in it. 5200 and 4200 are actually adhesives and not caulks. I wouldn't use either for your application.

Sudbury 321 is decent too.

Life Caulk is the wrong product for your application. Life Seal is the one you want to use for anything that can get below the waterline. It's a Polyurethane/Silicone combination sealant that has much greater adhesive properties with metal and fiberglass than Life Cauk, which is best for wood. I use Life Seal for almost everything these days. It stays flexible and is much easier to remove than 4200/5200.

Doc, it's the other way around. LifeCalk is more durable/longer lasting - and stronger (more adhesive qualities), although that doesn't matter in this case - than LifeSeal. BOTH LifeCalk and LifeSeal are totally fine for under the waterline use (again, LifeCalk being "better" than LifeSeal there). The downside to using LifeCalk is it takes longer to fully cure (although spritzing with water can help) and is MESSY. Messy as in you keep wondering how it gets on your fingers without your fingers ever touching the stuff. It's a mystery. But, EXCELLENT stuff.

Oh... forgot to add... if memory serves (which it may not!), I believe LifeCalk can actually be APPLIED underwater. I'm sure there are caveats such as go slow so you don't physically wash/push it out, etc, so it's really just an "emergency" thing to get you home. As far as emergencies go, there are certainly better things, such as a toilet bowl wax ring or pieces of closed-cell foam. But it really is great stuff.

I believe you are correct lifecaulk can be used above and below waterline.

Since the original question was about sealing the transom cap and usually that is above the waterline, there is no need for below the water line requirements for the sealant/caulk. As I mentioned, adhesives are for adhering parts that fit well and don't move relative to each other. Those applications may or may not be below the waterline. Caulks on the other hand are meant to fill gaps and seal. I am not sure exactly what the definition is for a 'sealant' . When I have some idle time, i may look it up!

Terminology definitely gets confusing. I don't think there is any "standard" that manufacturers abide by, either. Besides just being a sealant (which I would generally equate/interchange with caulk), you can have adhesive-sealants.... and then "how" adhesive is the sealant. Most, if not all, adhesives will ALSO seal simply due to what they are doing/what they are. But I totally agree that something like 5200 is absolutely the wrong product to use. Then there's also the question of whether something is UV stable (4200/5200 is not) and whether any of the sealant is going to see the sun (or reflected from the water).

There's obviously more than one choice here, and it really comes down to what a person's "favorite" is. For me, I've been using the BoatLife stuff for nearly 20 years and they haven't let me down. Plus, I only need to decide between two products for everything I do... LifeSeal or LifeCalk. In this particular case, since there are mechanical fasteners being use, there's no need for a strong adhesive (all sealant will be at least somewhat adhesive due to their nature) so I'd use the LifeSeal... and it saves me from having stained fingers for the next few days if I had used LifeCalk... since I almost never think to use gloves till AFTERWARD. You know, the whole "I'm not doing a whole lot of sealing here - I'll be careful - why waste the extra 30 seconds to go and get gloves" mentality.

Side note... as of the last few years, I've also started to use butyl rubber tape... which is probably the king of sealants when used between two things (bow rail stanchion plate, for example).

This month’s issue of a Boating magazine has an article about marine adhesives like 5200, Life Caulk, Life Seal, silicone and other products. After reading the article I’m going with Life Seal for my through hulls and penetrations

Graybeard said:

This month’s issue of a Boating magazine has an article about marine adhesives like 5200, Life Caulk, Life Seal, silicone and other products. After reading the article I’m going with Life Seal for my through hulls and penetrations

Click to expand...

I have to install a thru-hull transducer later this spring. I was planning to use 3M 4200 but will take a close look at Life Caulk or Life Seal as an alternative.

I should have refined my comments on LifeSeal vs LifeCaulk. I had a bad experience using LifeCaulk for the same application as the original poster. After using a gel toilet bowl cleaner containing HCL to remove tannin stains from my hull, I got a bunch of corrosion around the edge of the aluminum transom cap. Apparently, some of the gel got under the aluminum and didn't get rinsed out. I accidentally picked up a tube of LifeCaul instead of LIfeSeal so I went ahead and used it to seal the edge of the aluminum cap. After a few weeks, the sealant had pulled free from the aluminum surface but remained bonded to the fiberglass. Either the LC didn't bond well to the oxidized aluminum or the mechanical force on the cap caused by the engine operation physically pulled it away from the aluminum surface. After cleaning everything up with debond, I used LifeSeal and the seal has held up for over 2 years. The LIfeSeal is still flexible.

And yes, that LifeCaulk was some of the messiest stuff I've ever worked with. LifeSeal is just like using silicon sealer.

I've been working with that LifeCalk for a long, long time and I STILL can't manage to keep it off me! I swear I'm being careful, but then I look down at my hands and CRAP! There it is!

Doc, I suspect what happened in your case was the LC didn't originally stick well because of the corrosion - and nothing would have. Between the LC pulling some of the corrosion off with it and you cleaning better, whatever you put on next would stick better. There's no question about it though, the LC has a more tenacious grip than the LifeSeal - LifeCalk absolutely creates a stronger bond than Life Seal. But Life Seal is still great stuff, too. When I say I've used it for years, I mean I have literally used dozens and dozens of full size tubes of both LS and LC - between my various boats, my friends/family's boats, the marina where I work part time and even around my home.

The Lifecaulk got hard and brittle. And as you said, it forms a stronger bond. That's why I suspect that the flexing of the aluminum cap may be what caused it to break away from the metal.

Hard and brittle? Hmmm... that's strange. It typically forms into a rubber-type consistency with good flexibility - but not as hard as tire rubber. I don't think there's anything you did to cause the hard/brittleness. Maybe it was a bad batch or something. Definitely not the "norm" for the stuff.

I'm hoping that somebody has advice... related to this topic... I tried searching but haven't found the answer yet and I'm hoping to avoid going to a mechanic. I noticed yesterday that the aluminum (transom cap) on my 2002 192 seems to be lifting on one side and I can see the material underneath it (I presume it's plywood, between the fiberglass... the material inside does look solid). The screw that is supposed to hold down each side of the aluminum cap is still in place but the cap popped up over it on one side. I'm hoping that this isn't an indication that I have transom issues or anything serious, but I didn't want to attempt to re-attach the thing if it's just hiding a potential problem with the transom. I had heard of earlier transom concerns with older Grady's, so I'm hoping that this isn't anything to be too concerned about. Anybody have any thoughts? Thanks very much!

That's a pretty common thing with boats of that era. Mine is a 2004 and it also came from Grady with an aluminum transom cap. They realized the error of their ways and have since switched to some sort of a plastic material that isn't susceptible to corrosion like aluminum. The aluminum being in contact with the engine is acting more or less like a sacrificial anode and corrodes faster than normal. Mine was in about the same shape as yours when I decided to repower so I used that time to replace it with the new stuff they are using. You can buy it through your dealer. Some guys use stainless steel angle for this. There are threads about this very thing. Recently a member called "trapper" posted pictures and methods of this very project. He is a perfectionist and "sea sensible" and it shows in this thread. Following that thread makes the job doable by most DIYers. The fact that you can see some of the inards of the transom doesn't necessarily mean you have a problem but it is definitely a heads up that says you should investigate and nip it in the bud.

Thanks Halfhitch. I'll follow up accordingly. Everything looked dry and solid, and from what I was able to find it seems like GW started using a poly material in the transoms around 1998 so I'm sure I'm ok, but I do want to at least re-seal that area since I can't imagine it's great having water seeping under the cap and potentially into the transom (even if it's not wood). Thanks again.

Used LifeSeal for my thru-hull transducer. Will see this Sunday if it leaks.

GE Silicone at HD is a low cost alternative for above the waterline. Used to caulk the decks on GWs.