question on delamination epoxy.

So I have fixed one delam last year. This year I found a spot on the other hull to fix. Last time I used the git-Rot. I was wondering has anybody tried the Polyurethane epoxy for concrete cracks. The nice thing is it comes in a two part caulk tube and has a mixing tip. Which would make it a lot easier and it is available at Home Depot/Lowes. What do you guys think

You should check it for compatibility with the foam. Usually poly will eat foam and epoxy is safe.

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Bryan
Poplar Grove, IL
1977 Hobie 16 (died a spectacular death https://youtu.be/Y7O22bp2MVA)
1978 Hobie 16

So I also have a question regarding epoxy delam repair. How is the epoxy able to bond to the inner glass/foam when there may be all sorts of contamination from moisture or salt from over the years.

To original question, I wouldn’t use the concrete polyurethane because the viscosity doesn’t work and from my experience with that stuff is that it hardens up way too fast to flow into where it needs to go. You need a low-viscosity bonding agent which is why Git Rot works well (it’s very flowable).

Regarding contaminants raised by another, think of it in broader terms—the epoxy works in repairing delam issues and there’s not a better solution (apart from a different boat) that works reliably.

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H16 2002 "Islands" Sail No. 107432

If the foam core is wet, then the epoxy probably is not going to work. You would definitely want to make sure the boat is dry before injecting. Get some air circulating inside the hull for a few weeks before repairing to dry it out. You may even want to install an access port to increase air circulation. However, since the foam core is only on the sides of the hull and the deck, wet core usually isn’t a big issue since any water that may have accumulated in the hull over the years would have sat down in the keel, which is solid fiberglass.

From a technical standpoint, epoxy injection may not necessarily the “best” method for repairing delamination for the reason you mentioned- it’s impossible to guarantee that the bond surfaces are clean and free of contaminants. It’s also impossible to ensure that the epoxy flows to all of the delaminated areas or that the repair area is compacted while the epoxy cures.

But from a practical standpoint, injection is pretty much the only realistic way of salvaging, or extending the life of an older boat. The alternative would be to cut out the delaminated fiberglass and foam core, and bond in new core and fingerglass. That’s just way too much work when similar results can likely be had by just popping a few holes in the hull and squirting in a bit of epoxy.

sm

Does cutting holes for inspection ports in front of the forward pylons adversely impact hull integrity? If not, it seems like a nice way to keep the hull dry between outing...just leave the hulls open to breathe.

Cutting access ports in front of the forward pylon is generally considered to be a bad idea. But installing a port behind the forward pylon is ok. You will need to unlace the tramp and move it out of the way in order to have access to cut the hole. You will likely also need to “bed” the access port ring in thickened epoxy in order to account for the curvature of the deck.

I did this on my Hobie 14 using 4” ports and it has worked well for keeping air circulating constantly through the hull and keeping the fiberglass dry. I even fashioned an extra set of access port cover plates with a hole and a PVC 90 degree elbow glued into them to allow airflow but help keep rain water out during storage.

sm

If you are going to install an access port, I recommend you do all the repairs to the inside of the hulls before you place the access port in the new deck hole. It is a lot easier to put your hand/arm/tools/etc. thru the larger access hole than thru the smaller diameter access port.

I have big hands so I personally liked using the larger curved 5" access ports (if you can find them) when I rebuilt the transoms on my previous 82H16.

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Tim
84 H16
82 H16
87 H14T
Tortola Sails: 115222
Blue Prism Sails: 88863
Clearwater, FL

I agree with the above. Without the access port installed, you will have 1/2” more room to work. Doesn’t sound like much, but when you’re trying to move your hand around inside a small opening, every half inch counts.

The earlier question was about using an access port for ventillation. In that case, a 4” diameter port will be fine. But if you have to do an actual repair inside the hull, you will likely need at least a 5” port. I can barely get my arm into a 4” opening past my elbow, let alone have any room to see what I’m doing.

sm