Gelcoat on GitRot

Hi,I am in the preparation stage of repairing a small soft spot (4"x 3")on the hull of my H16.I purchased the GitRot epoxy for this and was wondering if anyone has had any problems with this epoxy bonding with the gelcoat?If so,what epoxy resin works best with gelcoat?
Also...are 3/16" drill holes good for the vent holes?
Thanks.

From what I can tell, you should use an epoxy resin(pricy) VS a polyester resin for a delam repair. There are several threads on Cat Sailor forums about the different types of epoxy and what will stick to each other or not.

Sam

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Sail Like you Have a Pair
Bluish gray 73 - 83 H16
Super Nice Yellow 84 H18

I've read in the forum from various posts where the recommended fix (repair) for a delam is epoxy resin, vs polyester... The boat was originally made using polyester resins, with the foam being 3/8" divinycell (PVC based). If you think about it, a delam fix is only going to be as strong as the surrounding foams strength. With this thought, polyester resin should be adequate for a delam fix. Regarding your question on epoxy & gel coat, epoxies will adhere to gel coat, where gel coats won't to epoxy (for very long). Question I have for you is why would you want to bond epoxy to gel coat in the first place? Gel coat is the last product you should be using in a fix unless you are making something in a mold. A 3/16" vent hole should be plenty big for a vent...you may find 1/8" will work also, as it depends on the viscosity of the resin you plan on injecting. You can thin polyester resin with styrene monomer if needed. GitRot was originally used for dry rot in wooden boats (hence the name GitRot). Your Hobie won't rot....

Point taken on the foam core sandwitch and polyester product. Now, I do not think he was worried about using gelcoat for the fix, but more to finish the job, there for the need for gelcoat to bond to resin.

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Sail Like you Have a Pair
Bluish gray 73 - 83 H16
Super Nice Yellow 84 H18

Hi Rick, Banzilla is right in that I just want to try and finish + match (as much as possible) the drill holes with the existing hulls.
So the answer is the gelcoat will not permanently bond to the epoxy.It will over time crack and seperate depending on the amount of flex in the hull.
Thanks guys for all the info.
I'll use the 1/8" drill for starters and if that doesn't work I'll move up.

Good luck. Let us know how it goes. I am about to do a rather large repair on my 71 or 72 hull.

Sam

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Sail Like you Have a Pair
Bluish gray 73 - 83 H16
Super Nice Yellow 84 H18

I just did this last weekend. I used Git Rot, I had to drill 1/4 holes to get it in, it needed a lot of holes (16 in all) and a lot more Git Rot than expected (almost a quart). Git Rot seems to soak in as it hardens because I was left with small divots in each hole. The holes were filled with polyester resin and sanded smooth. I plan to spray the gelcoat this weekend.
What I haven't figured out is how to recreate the non-skid surface where I drilled some holes.

I used to be a base manager for a fractional sailing base, and whenever a new boat was commissioned and there were some blems in the nonskid, they'd send out a factory authorized guy to do the repair. Let me tell you that they never got the hatch marks to line up. You could always seem them, even on a $250K boat.

With that being said, one of my buddies is a special effects guru. We've used silicone to create all kinds of tricky molds. I would at least attempt to make a mold of some good non-skid, and press it down onto a test patch of your laminating goop of choice and see how it turns out. Luckily, silicone sticks to almost nothing else, so you should be able to peel it away with no problems.

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Sea ya,
Chris Larsen
Co-Pilot of the Hobie Getaway
"The Twins"

~~(\_~~

I did this Git Rot repair on my hulls as well. What I did to get the gel to adhere was re-drill some small "dimples" where I originally inserted the git rot. Then I covered the dimples with some polyester resin before I did the gel. It worked great. The gel does not adhere to the git rot very well at all.

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James
86' Redline Hobie 16
Sail # 76909

Thank you abbman,I will give that a try.
This forum is fantastic....lot's of technical info.

One more thing, running the drill in reverse when making the dimples really helps you control the drill and not go all the way through the git rot. You just need a little dimple, like on a golf ball.

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James
86' Redline Hobie 16
Sail # 76909

Hi Guys, It was nice and cool up here in Canada on Sunday so I did my delam repair.It went great.Followed matt millier's advice,but used a 60ml syringe that I purchased from the local vet.I'll let it cure all week and then on Friday/weekend I'll do the polyester resin and gelcoat.
FYI..I drill 1/16" breather holes and a 5/32" filler hole.
Thanks again for everyones input.......now if I could just get my hands on a set of EPO rudders without my wife finding out,life would be great!