Caulk Between Spray Rail and Hull

jsakovits

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31' Eastern
The caulk between the PVC spray rail and hull is gone in a number of places. On one side of the gap is bottom paint the other side Awlgrip. Was thinking of either Lifecaulk or 5200 due to resilience and resistance to diesel fuel (over fill vent) but know both of these products can be more difficult to clean up if just want to keep product in gap. Any suggestions?

Thanks
 

Eastporter

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Sold- 20' Eastporter (Rebuilt 2011) 22' Pearson Ensign
I used 5200 but the Sudbury caulk looks like good stuff. Clear is a nice option too!
 

El Mar

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Downeaster

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The caulk between the PVC spray rail and hull is gone in a number of places. On one side of the gap is bottom paint the other side Awlgrip. Was thinking of either Lifecaulk or 5200 due to resilience and resistance to diesel fuel (over fill vent) but know both of these products can be more difficult to clean up if just want to keep product in gap. Any suggestions?
My vote is for Sikaflex 291. Comes in both fast and slow dry formulations and is popular stuff in certain boatbuilding regions - I've specified only it for my build. At the very least, I'd recommend avoiding 5200 as it's tension strength could well exceed that of iso or even vinylester resins (effectively the bonding agent between your color coat and the laminate). It is very good stuff but regard it as a 'forever' (i.e., nearly unrepairable) bond.
 

Eastporter

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RE: 5200
I have heard so many people say that 5200 is a forever bond etc. The true story (personally) is that I wanted to use 5200 to bond a small piece of 2x4 to my newly rebuild transom so I wouldn't have to drill and mount my transducer to the transom below the waterline. I cut lines in the wood, filled and coated with 5200, and even put a bead of 5200 around the block (smoothing it with my finger). The block cured and I thought it would last forever. I mounted the transducer- I gave it a little bump to make sure it was solid after a week. It came off easily in my hand with no tools or extreme force. Long story short, I took the block off, and mounted directly to the transom with screws and 5200 for watertight seal. I have heard stories that 5200 will keep a keel or transom bracket on without mechanical fasteners. I don't know- but I prepped the area (epoxy primer with no bottom paint) and tried to make it bond but it failed.
 

F/V First Team

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We use Rule 300 and SikaFlex 292 in the shop, those are our go-to adhesives and sealants. Above and below the waterline. 292 being for the more permanent fixtures, you can (with some effort) get the 300 apart and replace/repair if needed.

292 is sandable and paintable, giving it a slight advantage over 291 which is still a good product.

More Information: Bonding
 

Pedlyr

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I have never had good luck with 5200 and plastic. I don't think it will cure right 'cause of the oils. So I have been told.
 
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