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Caulk, Sealant & Epoxy reccomendations!

William Carwile

New Member
Hello everyone!

I am about to convert my rudder from the old to new style and was hoping to get some explanations and recommendations of different products to use. My boat currently picks up about a gallon of water per hour so I figured while i'm working on the rudder, i might as well seal/fill everything that's obvious...

I tried searching but i never can find anything relevant (womp womp!). Essentially my two main questions are regarding the inspection port and other random holes from old hardware (there's a lot on my boat for some reason).

When it comes to the inspection port I've heard both 4200 and 5200 as recommendations, but some say 5200 is too intense. Thoughts?

When it comes to small (I'm talking Ø.250" max) holes from old bolts & hardware, what's the best to fill this? Can i use the same 4200 or 5200 or should i get an epoxy like Marine Tex???

Any comments or suggestions would be greatly appreciated!

Thanks!
 

leob1

Member
For inspection ports I've used silicone. West Marine Marine Silicon is fine. For holes in my Super Porpoise I used epoxy and fiberglass cloth. I ground out around the hole to made a depression, then cut the cloth so it was just a bit smaller, and a second piece a bit smaller than that. Mix some liquid epoxy, and wet the cloth covering the hole. Let it cure, sand\file the high spots and ridges. Then a layer or two of Bondo and sand smooth. Then I went over the whole boat with glazing putty filling in the dings and scratches in the gel coat. Finish with primer and paint.
 

William Carwile

New Member
I would do an airtest before putting the port in. One less thing to seal.
I do plan on doing an airtest, but i was going to wait until after this season because I already know there is a lot I'm going to need to address. I'm more concerned in the short term because I want to switch the rudder hardware and be back on the water in a week or so.

For inspection ports I've used silicone. West Marine Marine Silicon is fine. For holes in my Super Porpoise I used epoxy and fiberglass cloth. I ground out around the hole to made a depression, then cut the cloth so it was just a bit smaller, and a second piece a bit smaller than that. Mix some liquid epoxy, and wet the cloth covering the hole. Let it cure, sand\file the high spots and ridges. Then a layer or two of Bondo and sand smooth. Then I went over the whole boat with glazing putty filling in the dings and scratches in the gel coat. Finish with primer and paint.
For just filling the holes left by the old rudder hardware do i really need to involve fiberglass cloth? For holes that small i guess i was hoping it wasn't necessary. However, I've never done any work involving fiberglass before so maybe my hopes were more dreams, and i should just crush them now... haha
 

beldar boathead

Well-Known Member
For just filling the holes left by the old rudder hardware do i really need to involve fiberglass cloth? For holes that small i guess i was hoping it wasn't necessary. However, I've never done any work involving fiberglass before so maybe my hopes were more dreams, and i should just crush them now... haha
You don't need fiberglass cloth for something like that. I have heard of people using 5200 for that type of thing (I would NOT use 5200 on an inspection port as if you ever want to remove it or replace it, it ain't happening if you use 5200!) Marine Tex is also great for hole-filling but it is pricey. I would think a JB Weld or similar epoxy putty would be perfect for this, and cheaper than Marine Tex. Epoxy Putty Sticks
 

signal charlie

Well-Known Member
Staff member
If you want to seal something use a sealant, if you want to adhere something use an adhesive. The 4200 and 5200 claim to do both, but the are heavy n the adhesive end of the scale.

For now, go sailing and drain the boat frequently :) In some States, Summer is almost over!

For the port I'd select a marine grade sealant. 3M makes Marine Grade Silicone Sealant code MG Sil, TotalBoat makes TotalSeal, etc...I would avoid the 3M numbered adhesive products for use as a sealant as they will be very hard to remove. And for sealing a port, I wouldn't mind using a high grade exterior caulk sealant found at Lowe's or HD or ACE etc...Maybe I've done that recently on a boat...

For random old holes we used to exclusively use MarineTex Epoxy Putty, one repair kit took care of most of the fastener holes on one boat. Now we use TotalBoat THIXO thickened epoxy from a high thrust caulk gun cartridge or Pettit Flexpoxy, depending on which brand we have rapid access to. TotalBoat is least expensive and ships free. With either product the cartridge dispenses the proper ratios and you can put the cap back on and use some more later in the year. If your holes are any bigger than screw fastener size I'd go the epoxy route with 4 oz fiberglass cloth. The epoxies have structural qualities, they can be sanded, painted and drilled and are good for underwater use. I don't think the 3M products are rated for continual immersion.

Here's a little daggerboard trunk repair with Marine Tex, get the white vs the gray and it will match pretty good.

Scout daggerboard trunk marine tex.jpg

FLEXPOXY is great on 139 year old wooden rowboats too. It can be dispensed through the mixing tube or put into a syringe for tighter areas.

Audrey Barbashela Flexpoxy silicone bronze.jpg

IMG_9585.jpeg

We get our materials mostly from Jamestown Distributors now, their in house brand is TotalBoat and it has a good price point. They also sell Interlux and Pettit and some RustOleum, plus all of the rollers and cups and gloves to go along, a lot of it is added in free. If we shop local we have a couple of West Marines to pick from, or Lowes has sealant and RustOleum, including RustOleum Topside Marine Paint.
 

palumanic

New Member
I recently found an ad on the internet for a boat for sale. The price was quite low, although the seller explained that some problems could easily be fixed, he just doesn't go out to sea anymore and he doesn't need it. I decided to take this boat in addition to my main one. I sanded it down as there were minor scratches and painted it. And when it was time to test it on the water, the boat started to take on water. I was looking for some good silicone to give all the holes a good seal, but it turned out that there were a lot of them. It was challenging to choose, but I decided on the silicone that I used on my concrete driveway.
 
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