Graphite bottom application

See our FAQ and tutorials before posting.
Dougster
* Bateau Builder *
* Bateau Builder *
Posts: 3296
Joined: Tue Jun 06, 2006 11:05 pm
Location: Texas

Re: Graphite bottom application

Post by Dougster »

I faired the bottom of my boats with quickfair in places. Sure, Oyster reefs hit hard will score it, but Graphite/epoxy mix over unfaired glass is not at all impervious to scoring either. I tend to just not look underneath the boat much :oops:

Dougster

User avatar
cape man
* Bateau Builder - Expert *
* Bateau Builder - Expert *
Posts: 8268
Joined: Sun Jan 20, 2008 12:02 pm
Location: Lithia, Florida

Re: Graphite bottom application

Post by cape man »

I put it directly on a glassed and sanded bottom and then faired it with graphite mixed with epoxy to a thicker consistency in some low spots that showed up. Put over 4 layers on before I was satisfied. WEAR a mask when sanding!
The world always seems brighter when you've just made something that wasn't there before - Neil Gaiman

User avatar
BarraMan
* Bateau Builder - Expert *
* Bateau Builder - Expert *
Posts: 2164
Joined: Tue Dec 11, 2012 3:44 pm
Location: Australia

Re: Graphite bottom application

Post by BarraMan »

I faired the bottom then applied 3 coats of epoxy followed by 3 coats of epoxy/graphite, lightly sanding between each graphite coat.

wpstarling
Frequent Poster
Frequent Poster
Posts: 102
Joined: Fri Mar 27, 2020 12:23 pm
Location: Crawfordville, FL

Re: Graphite bottom application

Post by wpstarling »

All good stuff, seems that there isn't just one way to do it and it depends on a) what you want the finish to look like and b) how much you're willing to go through.

I'm definitely going to fair the sides and just put graphite/epoxy over that, but the bottom I'll have to wait until I'm done sanding and make the judgement call there on if I'll fair first.

Thanks everyone!
Boats restored: 1973 Glastron CV16, 1990 Proline 17 CC, 1993 Bass Boat
Boats built: custom 15ft flat bottom skiff, Soon-to-be-built TX18 (originally dborecky's build)

User avatar
VT_Jeff
* Bateau Builder *
* Bateau Builder *
Posts: 1857
Joined: Fri Oct 25, 2019 6:32 pm
Location: vermont

Re: Graphite bottom application

Post by VT_Jeff »

BarraMan wrote: Fri Oct 22, 2021 2:42 am I faired the bottom then applied 3 coats of epoxy followed by 3 coats of epoxy/graphite, lightly sanding between each graphite coat.
Now THAT's a bottom!
There are only two seasons in Vermont: boating season, and boat-building season.

Completed Paul Butler 14' Clark Fork Drifter
Completed Jacques Mertens FS14LS + 10%, Build Thread
Started Iain Oughtred Tammie Norrie

wpstarling
Frequent Poster
Frequent Poster
Posts: 102
Joined: Fri Mar 27, 2020 12:23 pm
Location: Crawfordville, FL

Re: Graphite bottom application

Post by wpstarling »

I wanted to update what I did so someone else would know :)

I sanded the bare fiberglass and, while relatively smooth, it wasn't what I wanted to have as my surface before graphite/epoxy so I put a layer of quikfair down, sanded it smooth and then put 4 coats of graphite/epoxy over it. I could have done 2 thin layers of quikfair and then the graphite/epoxy and it probably would have looked real smooth but my outcome is good for what it is (the bottom of a small skiff).

I did have another question though. Has anyone done the entire bottom with graphite/epoxy? And by entire bottom I mean all the way up to the rub rail. I was thinking on my next boat of doing that and just using the UV resistant epoxy with the graphite for the last layer or 2 so that it doesn't fade/chalk over from the sun light. Any thoughts on this?
Boats restored: 1973 Glastron CV16, 1990 Proline 17 CC, 1993 Bass Boat
Boats built: custom 15ft flat bottom skiff, Soon-to-be-built TX18 (originally dborecky's build)

User avatar
cape man
* Bateau Builder - Expert *
* Bateau Builder - Expert *
Posts: 8268
Joined: Sun Jan 20, 2008 12:02 pm
Location: Lithia, Florida

Re: Graphite bottom application

Post by cape man »

If it is above the waterline and exposed to the sun it is going to get VERY hot! While you might be able to protect it from UV I would worry about it getting softened by the sun and the heat.
The world always seems brighter when you've just made something that wasn't there before - Neil Gaiman

wpstarling
Frequent Poster
Frequent Poster
Posts: 102
Joined: Fri Mar 27, 2020 12:23 pm
Location: Crawfordville, FL

Re: Graphite bottom application

Post by wpstarling »

cape man wrote: Fri May 27, 2022 9:15 am If it is above the waterline and exposed to the sun it is going to get VERY hot! While you might be able to protect it from UV I would worry about it getting softened by the sun and the heat.
This is a good point. The fact it'll be hot isn't much of an issue for touching since it's the outside of the boat but I didn't think about it softening or messing with the rigidity/quality of the epoxy/boat. I'll look into this and maybe some others can chime in. I searched and couldn't find where it had been done before.
Boats restored: 1973 Glastron CV16, 1990 Proline 17 CC, 1993 Bass Boat
Boats built: custom 15ft flat bottom skiff, Soon-to-be-built TX18 (originally dborecky's build)

pee wee
Very Active Poster
Very Active Poster
Posts: 2276
Joined: Sun May 01, 2011 8:29 am
Location: Georgia

Re: Graphite bottom application

Post by pee wee »

Dark colors (paint or graphite) in a southern climate will heat up and can allow the pattern of the fiberglass to telegraph through. Don't know how much of an issue that would be for you.
Hank

TomW1
Very Active Poster
Very Active Poster
Posts: 5844
Joined: Sun Apr 19, 2015 10:57 pm
Location: Bryson City, NC

Re: Graphite bottom application

Post by TomW1 »

Epoxy and black do not mix well in high heat areas or direct sunlight. Keep the epoxy/graphite mix to the waterline or a couple inches above it. Then use a lighter colored paint above that. The darkest I have seen in FL is a bright red, there may have been a smaller 14' in dark blue. The biggest thing to remember is heat weakens epoxy.

Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

Post Reply

Who is online

Users browsing this forum: No registered users and 12 guests