Silicone question

Cdnguy1980

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Was power washing my new old boat today and found tooled silicone between the hull and upper deck sides ( where the cleats would be) is this normal? It goes from bow to stern
 

Cdnguy1980

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Sorry I meant to say it was under the deck sides, as if to keep water out of the hull from under the sides, if I had to guess it's because they are not sealed by welds, it's an aluminum boat from about 1977
 

roscoe

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My guess is that a previous owner did this.
Doesn't sound like anything a manufacturer would put any effort into.
 

Chris1956

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Where fiberglass hulls meet their caps, silicone is often applied to seal the seam. This is usually covered by a rub rail.

Not sure is aluminum boats get this treatment.
 

Cdnguy1980

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Where fiberglass hulls meet their caps, silicone is often applied to seal the seam. This is usually covered by a rub rail.

Not sure is aluminum boats get this treatment.
Yeah it was under side step/rub rail as you mentioned, I'm going to leave it still I have the boat paint stripped and then assess. There was some sort of sealant at the seams on the bow on the interior that I will be re-sealing as it was NFG due to time
 

jbcurt00

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A lot of silicone is non-paintable.
They do make some now
Most silicone caulk use acetate to cure which is caustic to aluminum.

There are better choices for an aluminum boat and w/out seeing pix, hard to say if silicone was actually necessary.

Many areas of aluminum boats 'look' like a sealer/caulk should be used but are in fact applied to a solid sheet of aluminum so all adding caulk does is potentially trap water. Esp bad in norther climates w freeze/thaw. As an example, the keel strip and side rails on an aluminum Starcraft should never be caulked.
 

Cdnguy1980

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Most silicone caulk use acetate to cure which is caustic to aluminum.

There are better choices for an aluminum boat and w/out seeing pix, hard to say if silicone was actually necessary.

Many areas of aluminum boats 'look' like a sealer/caulk should be used but are in fact applied to a solid sheet of aluminum so all adding caulk does is potentially trap water. Esp bad in norther climates w freeze/thaw. As an example, the keel strip and side rails on an aluminum Starcraft should never be caulked.
What should I use instead of silicone to reseal the bow plates then?
 

jbcurt00

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Post a pix of what you plan to caulk.

Boat maker & model?
 

Cdnguy1980

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The first pic is the inner hull at the bow the highlighted area is where I need to seal, the other two pictures are where the silicone was that I pulled off right where the red paint is. Also is enamel spray paint ok on aluminum if only for just the season? The boat was made by the Mermaid boat Co. The model is the Monterey 60 not sure if they were a shoot off of another major producer.
 

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jbcurt00

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No idea what the prior owner was thinking w the red caulk, but at least they did a bad job:unsure: what a mess.

It may or may not be paintable.

For the interior seams & rivets, use Gluvit not caulk, or Coat-It
 

Cdnguy1980

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No idea what the prior owner was thinking w the red caulk, but at least they did a bad job:unsure: what a mess.

It may or may not be paintable.

For the interior seams & rivets, use Gluvit not caulk, or Coat-It
What about sika flex sealant?
 
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