Beginner Beware: Soft Spot Repair (with pics)

Sent you a PM but maybe the info would be helpful to others as well so I'll post here.

My boat is stored on the beach. I was hoping to do the repair this week for the weekend but it looks like theres rain in the forecast for some days.

My question, does the repair need to sit in 48 hours of no rain completely dry as possible perfect conditions, or can it get its initial "setting" done within a few hours and afterward conditions are not as important? Its supposed to rain 24 hours after I was going to do the repair, and I'm not sure how that may impact the curing process.

Rain won't really have much impact. You don't want water to get into the core, so I'd wait to drill the holes until you're ready to do the full repair, but once you're done injecting, rain shouldn't really be an issue. The epoxy initially cures via an exothermic reaction (releases heat as it cures), so to be safe I'd try to do the repair when you've got a few hours rain free... I doubt the rain could impact the curing, but still. The epoxy will begin to solidify in about 20 mins, and will be pretty much solid after an hour or two. The full cure takes around 10-15 hours, but after an hour or two I think you'd be perfectly fine if it got rained on.

https://www.westsystem.com/hardener-selection-guide/

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Mike

'79 H18 standard 'Rocketman II' sail #14921 RIP
'78 H18 (unnamed) sail #14921
'08 H16 sail #114312
'97 H21SC sail #238

Really great link with helpful information. The website for west systems is a little tricky to navigate. Thanks for all your help. My H16 will be injected later this week!

Great info! My question is it appears you are epoxying under the foam to the top of the inside fiberglass? All the pics I have seen show to drill half way into the foam. I am not sure where my delamination is occurring...top fiberglass to the foam or the inside fiberglass to the foam? How deep did you drill down?

You just drill with light pressure until you’re through the outer layer of glass. The drill bit goes through the foam in about a half a second, so you’ll end up going through both. When you inject the epoxy, it’ll fill the void wherever it is… if the top layer is delaminated, it’ll fill there, if it’s the bottom layer, it’ll fill there. Just do long as you don’t drill through the inner layer of glass. Not sure exactly why, but all my delaminated spots were between the inner layer and the foam (or at least the ones I later cut into).

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Mike

'79 H18 standard 'Rocketman II' sail #14921 RIP
'78 H18 (unnamed) sail #14921
'08 H16 sail #114312
'97 H21SC sail #238

Put a little piece of masking tape on your drill bit about 1/4” from the tip to act as a reference point as you drill through the outer skin. Like Sabres suggests, only use light pressure when drilling. As soon as you drill through the outer skin - stop. Drill all of your holes through the outer skin and then take the drill bit out of the drill and run the bit back through the holes, spinning it with your fingers, until you hit the inner skin. This is the safest approach IMO, otherwise you risk blowing through the inner skin. The inner skin is only a coulple layers of fiberglass, much thinner than the outer skin and very easy to go through if using a power drill.

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When I add an access port , I flip the hull over (gravity is your friend here) and add supportive two fiberglass battens (standing on edge) cut from old main sail battens that have been detailed to match the inside arc of the deck. I first use a wood paint stirring stick an a template to verify a tight fit. Place these battens on each side on your cut hole about three niches from that hole to avoid conflict with the fasteners. Be sure to span all the way to met each side of the hull and resin in place. Now, this adds more than enough support if and when someone steps on the access port. Do not weaken the deck when adding an access port..........

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Bill 404 21SE