Bottom epoxy/graphite

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VT_Jeff
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Re: Bottom epoxy/graphite

Post by VT_Jeff » Thu Feb 13, 2020 4:10 pm

BrianC wrote:
Thu Feb 13, 2020 3:11 pm
VT_Jeff wrote:
Thu Feb 13, 2020 2:37 pm
Interesting side topic: Do you carry an emergency patch kit? I'd be interested to know how people do field repairs on these cored-composite boats, and what they carry in the boat for emergency "get back to port" repairs.
When sea kayaking, we always carry some Denso tape - basically a strong fiber tape with a thick bitumen layer that sticks to the hull, even when wet. It comes in 6" wide rolls and has a plastic film covering the sticky side. Just cut off a piece, peal the covering, and slap over the hole.
Going to look into that, at least for our SUPS which we need to field repair from time to time. I know some whitewater kayakers who use something like Bitchathane(no idea on spelling, I just recall te conversation about it) for emergency repairs on plastic kayaks, I guess it's some type of roofing material. Maybe related to Bitumen?

Edit:

Looks like it's Bituthene I was thinking of and it is related to Bitumen.


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Re: Bottom epoxy/graphite

Post by cracked_ribs » Thu Feb 13, 2020 6:15 pm

VT_Jeff wrote:
Thu Feb 13, 2020 4:10 pm

Looks like it's Bituthene I was thinking of and it is related to Bitumen.
This reminds me of the time I described something as "bitulithic" to a friend of mine.

Of course he heard "bitchalithic", which he understood to be sort of like monolithic, but...

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Re: Bottom epoxy/graphite

Post by terrulian » Thu Feb 13, 2020 6:56 pm

Jaysen's right...I was talking merely about touching up a scrape that went through the epoxy.
If you hit something hard enough to put a hole in your boat, a patch is going to be the least of your problems, after an ambulance. These boats are made of iron. Don't know how the Captain did it without injury.
I had my hull crack on my 39 but it wasn't because we hit something. There's some fool on You Tube who powered his bateau design into a log and jumped it with no damage.
The question of a repair kit for putting a hole in your boat reminds me of the movie "All Is Lost" with Robert Redford, which is a collage of some of the most ridiculous sailing scenarios ever put on film. At the very beginning of the movie, he is asleep and wakes up to find he's hit a container, and there's a large hole in the hull. Two things: One, if you hit a container in a bluewater boat hard enough to put a hole in it, you're going to have a concussion and a dislocated shoulder. It's not going to be like your cat licked your face and awakened you. Second, he looks around and the sea is calm So...how was he going fast enough to rupture the hull at impact? Somewhere I have a list of all the nonsense in this movie, and it isn't a short list.
That said, you can buy epoxy that cures underwater for this sort of thing. I carried some aboard, as I did tons of emergency gear. We didn't need that particular thing, nor hardly anything else.
https://www.amazon.com/TotalBoat-Underw ... ive&sr=1-1
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Re: Bottom epoxy/graphite

Post by VT_Jeff » Thu Feb 13, 2020 7:30 pm

terrulian wrote:
Thu Feb 13, 2020 6:56 pm
...he looks around and the sea is calm So...how was he going fast enough to rupture the hull at impact?
Hilarious! I spent the whole movie trying to figure out exactly what boat he was sailing as I was shopping for a boat at the time. I ended up with a C&C29 MKII, I think his was a Sabre 34 or something, been a while.

Appreciate the info on the patching, I'll take a look, and wear a helmet!

Edit - Apparently it was a Cal39

Edit: https://www.sailfeed.com/2013/11/all-is ... ing-movie/
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Re: Bottom epoxy/graphite

Post by Capt UB » Fri Feb 14, 2020 9:20 am

terrulian wrote:
Thu Feb 13, 2020 6:56 pm
Jaysen's right...I was talking merely about touching up a scrape that went through the epoxy.
If you hit something hard enough to put a hole in your boat, a patch is going to be the least of your problems, after an ambulance. These boats are made of iron. Don't know how the Captain did it without injury.
I had my hull crack on my 39 but it wasn't because we hit something. There's some fool on You Tube who powered his bateau design into a log and jumped it with no damage.
The question of a repair kit for putting a hole in your boat reminds me of the movie "All Is Lost" with Robert Redford, which is a collage of some of the most ridiculous sailing scenarios ever put on film. At the very beginning of the movie, he is asleep and wakes up to find he's hit a container, and there's a large hole in the hull. Two things: One, if you hit a container in a bluewater boat hard enough to put a hole in it, you're going to have a concussion and a dislocated shoulder. It's not going to be like your cat licked your face and awakened you. Second, he looks around and the sea is calm So...how was he going fast enough to rupture the hull at impact? Somewhere I have a list of all the nonsense in this movie, and it isn't a short list.
That said, you can buy epoxy that cures underwater for this sort of thing. I carried some aboard, as I did tons of emergency gear. We didn't need that particular thing, nor hardly anything else.
https://www.amazon.com/TotalBoat-Underw ... ive&sr=1-1

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Re: Bottom epoxy/graphite

Post by terrulian » Fri Feb 14, 2020 9:40 am

Oh. :lol: :help:
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Re: Bottom epoxy/graphite

Post by Jaysen » Fri Feb 14, 2020 9:58 am

I like that solution to the problem. If I had a family motto it would have to be “hold my beer and watch this”
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Re: Bottom epoxy/graphite

Post by Capt UB » Fri Feb 14, 2020 3:02 pm

The SandPiper (FS14) was built heaver, with a cockpit deck (sole), no center bench, but more ribs/frames under the deck, 2 part foam, glass went up to the gunwales inside and out....
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Re: Bottom epoxy/graphite

Post by Dr. Pete » Wed Feb 19, 2020 10:10 am

Capt UB wrote:
Thu Feb 13, 2020 12:49 pm
My mix as follows: 8 oz of resin and 4 oz. slow hardener, then 1/2 cup of graphite power.

What I used;

BBC's Graphite, MarinEpoxy with slow hardener

What I did;

Shifted graphite a few times.
Mixed epoxy and hardener.
Added graphite slowly as I mixed.
Rolled on slowly.
Wet on wet, 1/2 to 1 hour between coats.
Total 3 coats, maybe 4?
Did not sand at all.

I guess we shall see if this holds up. So far, I dropped the boat on it's transom (no skig), hard!
Nothing cracked or chipped off! Also, it's very slippery!

Update, I hit a big log on the river at full speed with two of us in the FS14 (SandPiper). We came out of the water, I very slowly turned around and went back to the ramp to pull the boat out.... Checked bottom and inside, no problems!!!


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Re: Bottom epoxy/graphite

Post by VT_Jeff » Mon Jun 29, 2020 9:22 am

I just finished the graphite this morning. Wasn't as close as I thought when I started this thread. I went back and forth in my mind over and over whether to go the expoy/graphite route or some other route. I had talked myself into cheap black paint(an unfortunate fact is that this boat just won't be in the water a lot: I live in VT, it's a short season, and I have quite a few other water-craft) and was on my way to the hardware store to buy it. Luckily it's a long drive and before I got halfway there I had re-talked myself into the epoxy/graphite and here's why:

1. The cheap paint would not offer any protection to the soft, fairing compound areas and I remembered that when i did a neat coat of epoxy on the hull a few months ago, I skipped the bottom, planning on epoxy/graphite. I still had the option to neat coat and then paint but...

2. Paint would scrape easily and leave very visible marks that would bother me, but not enough to flip the boat and fix them, which means that within a short period the bottom would look like !@$ and probably stay that way.

3. With expoxy/graphite, I could get the bottom started and finished within a day or 2 with multiple coats, where paint would take days and days to cure, then would need to be sanded before the next coat and just generally be a lot more work.

So, epoxy/graphite was the clear winner.

I didn't use rollers. I tried in one small section and it just was not working for me at all. I heqated the epoxy in my cooker, mixed in un-sifted graphite from BBC until the mixture looked very black, poured it out(all of it), spread it with a knife or a fat stirring stick, then tipped it with a foam brush. I went through about half a box of foam brushes as they fatigue pretty quickly.

It came out.......OK. As someone else said, from 10 feet it looks pretty good. When you get close you can see imperfections in the tipping and the odd clump of graphite. But: it's black, fairly smooth/shiny, it's tough, it's going to stay mostly that way, and ................it's DONE!
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