Gel coat repair on keel

[Livewire]

Finally got around to attempting to repair the damage from previous owners beaching. I scuffed it up with some 220 grit sandpaper. Then cleaned it with alcohol. It was hard to keep enough spectrum paste on the keel edge. I used a plastic body filler spreader to even out the paste, but if I tried to smooth it out the fiberglass spots would show through. So I wound up just mounding it up on the edge. Going to have to sand gingerly as to not to remove too much there.

I’ll start the sanding process tomorrow after I get home from work.

 

[zipper]

Wow, was the PO's favorite beach a gravel bar? Looks better already.

 

[gthh]

Looks good! I scraped my keel retrieving my boat from a badly designed launch. The sanding was the toughest part. The tragic part of the process was I covered it all up with a Keel Guard, made me think I should have just sanded smooth.

See Below for some advise from @CrankyGypsy



CrankyGypsy

i just did this on mine (among other fiberglass/gel repairs). once fixed, i added a 9' KeelShield - so it wasn't necessary to be perfect, but looked so much better than epoxy/MarineTex would've prior to install. for my various repairs, i used spray guns or a brush, depending on the situation...

for this one i used a brush because it was going to be covered - though it requires more sanding, the brush made the repair simpler and very easy to clean up afterwards:
- allowed it to dry really well (though i'm pretty sure it was worn away so softly that there was no water intrusion into the glass)
- cleaned area with acetone
- taped (quality painter's tape) the area off a little bit away from the worn edge to allow blending with sanding
- scuffed the area with ~300grit and re-cleaned with acetone
- applied gelcoat (thoroughly mixed with 2% MEKP) with a quality brush. brushed in such away that it remained thick on the keel and tapered out thin to the taped edge. i feathered it quickly to accomplish this - you might want to practice with straight gel on a board prior to get the technique down.
- applied 2-3 layers (always tapering the thickness to reduce sanding), applying each coat within 15-20mins of the last coat (otherwise it will need to be rescuffed if it kicks/dries too much).
- no need to use/apply a curing agent - just allow gel to cure 24-48hrs (for shrinkage) and then wipe the skin off with acetone so sandpaper will not gum-up.
- started at 220/320grit using one of those very soft-foam sanding blocks from 3M to prevent pressure points. gradually worked up to 1000grit.
- followed instructions for the KeelShield - looks awesome.

i only went to 1000grit because my repair area was small enough to be under the KeelShield (like yours). keep the tape on while sanding with the rougher grits to use it as a thickness gauge and prevent sanding through the surrounding gel - remove tape when you get into the finer grits. might want to go to 1200-1500grit if you plan to compound and polish with a rotary afterwards. you're also going to be going back and scuffing the surface for the KeelShield if you decide to install one.

 

[biglar155]

Nice job.

The "before" pictures make me think of the scuffs in my gel coat caused by the bunk boards and say to myself "not really a problem."

 

[Livewire]

Just got in from sanding on the boat. Started with 500 grit and a block sander, what a work out. Mr. Miyagi would be so proud! Anyways here’s my progress for tonight. Only about a hour of wet sanding.

 

[Livewire]

Here’s after 1000 grit wet sand. I have some 1200 I could use, but I’m pretty happy with the results so far. Very smooth to the touch. Just like @gthh, I’m going to install a keelshield over it to help protect it. Hopefully tomorrow I can start the buffing process.

 

[CHRISTOPHER DOUGLAS]

Looks great
Looks like a DIY project how difficult was it 1-5 scale
Any advice shop or diy

 

[Canuckjetboater]

Finally got around to attempting to repair the damage from previous owners beaching. I scuffed it up with some 220 grit sandpaper. Then cleaned it with alcohol. It was hard to keep enough spectrum paste on the keel edge. I used a plastic body filler spreader to even out the paste, but if I tried to smooth it out the fiberglass spots would show through. So I wound up just mounding it up on the edge. Going to have to sand gingerly as to not to remove too much there. View attachment 73749 View attachment 73750 View attachment 73755 View attachment 73756 View attachment 73757 View attachment 73758

I’ll start the sanding process tomorrow after I get home from work.

@Livewire .....respectfully do NOT use alcohol as it leaves behind a film making adhesion difficult always use acetone as a prep clean-up and use it sparingly with a (damp not wet) cheesecloth.

 

[Troch1]

@Livewire .....respectfully do NOT use alcohol as it leaves behind a film making adhesion difficult always use acetone as a prep clean-up and use it sparingly with a (damp not wet) cheesecloth.

I always heard that it was only denatured alcohol that left a film, NOT isopropyl alcohol. Am I incorrect?

 

[Canuckjetboater]

I always heard that it was only denatured alcohol that left a film, NOT isopropyl alcohol. Am I incorrect?

@Troch1 ......I would not presume to doubt you and maybe it is I who am incorrect. I have always been told by gel coat techs to avoid alcohol as a prep product and to use acetone as it is from the same chemical family as the fiberglass/resins/coatings/paints and even helps with the bonding of the repair products. I have always used acetone on hulls and drives (a lot of them) as it works extremely well with the marine coatings and lacquers of OMC Cobra, Mercruiser and Volvo Penta as well as their primers and anti corrosion barriers. I have never had adhesion problems, blistering or compatibility issues when using acetone as a final prep after all wet sanding etc. has been done and in between sanding coats of spray lacquers and fiberglass repairs. That said, I am always open to new ideas!

 

[zipper]

I use acetone on fiberglass and gelcoat repairs and I use IPA to clean between layers of epoxy and polyurethane on woodwork. I have used acetone to clean epoxy but dont get it near the poly. I do use IPA on gelcoat before applying graphics based on manufacturors instructions.

8 Solvents for Cleaning Up your next Job

A major part of our business here at FGCI is dedicated to solvents. Solvents are used for many things, but especially for cleanup. When you finish a project, you want to be able to clean up your me…

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[Livewire]

Looks great
Looks like a DIY project how difficult was it 1-5 scale
Any advice shop or diy

It was a easy DIY project. Take your time and you’ll be fine. Use a block and hand sand it with 200-400 grit to remove the bulk of material. Use your fingers to feel how much material you’re removing and when you get close to matching the level of the hull. Step up to 1200 grit and wet sand. Then step up again to 2000. Walmart has sandpaper in a assortment pack up to I know 2000 grit. If you’re planning on a keelshield afterwards I wouldn’t worry about having it perfect. The keelshield will cover up everything.
Good luck!

 

[Livewire]

Didn’t realize I didn’t upload these to this thread.

 

[Canuckjetboater]

It was a easy DIY project. Take your time and you’ll be fine. Use a block and hand sand it with 200-400 grit to remove the bulk of material. Use your fingers to feel how much material you’re removing and when you get close to matching the level of the hull. Step up to 1200 grit and wet sand. Then step up again to 2000. Walmart has sandpaper in a assortment pack up to I know 2000 grit. If you’re planning on a keelshield afterwards I wouldn’t worry about having it perfect. The keelshield will cover up everything.
Good luck!

@Livewire .....great advice! I would also use a mini grinding tool to remove all loose/jagged edges of the damaged fiberglass/gelcoat before beginning, vacuum the area carefully, then use cheesecloth "damp only" with acetone (or cleaner of the owner's choice) before beginning to use repair material.