Gel coat

[David VanDenburgh]

I have a gel coat repair to make on Ariel before she splashes. We had an incident with a dock last summer that left a gouge in topsides that's perhaps 1/4" thick and about 6" long. It extends just to the laminate. Sorry, no pics; it was just too painful to record.

Does anyone have a recommendation for a specific product and a supplier? Should I use gel coat or would I be better off just going with epoxy for this repair?

Thanks,

David

[bhartley]

My Ariel had a run in with the dock also after breaking FIVE bow lines. No damage pictures either. I feel your pain!

I ground out the area and filled the area with Marine-Tex (not a very deep area). I used MT since I needed to do a lot of sanding to fit the contours of the stern corner. Prepped properly for compatibility (see their docs) and then used Jamestown's non-air inhibited gelcoat. The color was a great match, but it made the transom's gelcoat look horribly worn and porous.

So.... I just regelcoated the entire transom. Very happy with the results. The grind marks on the transom were faired with thickened gelcoat. I was very fortunate that the gelcoat was such a great color match straight out of the can.

That said I was VERY pleased with the sandability of Interlux's Watertite fairing filler and would use it instead of Marine-Tex if I had to do it again.

She'll be looking pretty again shortly!

Bly

[stone]

You could probally buy just a small amount locally. I always buy gel-coat and resin unwaxed and just add wax for my finish coat for sanding. I would think you could just thicken the gelcoat with cabosil for your first pass and then maybe one or two more passes till your fair again. I keep two catamarans on the beach here that I gel coat the bottoms every year before it wears thru to the laminate. I actually hit something and the centerboard jammed back into the hull. The repair is four layers of ten oz cloth then two coats of gel coat with wax added on the second coat. I came back the next day and sanded it smooth.

[Tim]

I have a gel coat repair to make on Ariel before she splashes. We had an incident with a dock last summer that left a gouge in topsides that's perhaps 1/4" thick and about 6" long. It extends just to the laminate. Sorry, no pics; it was just too painful to record.

Does anyone have a recommendation for a specific product and a supplier? Should I use gel coat or would I be better off just going with epoxy for this repair?

Thanks,

David

You can use gelcoat for this cosmetic repair. The most challenging part will be color-matching. Even though your hull is white, fresh white gelcoat will not match: all white hulls subtly (and sometimes drastically) change color after years of UV exposure, etc. So buy a simple gelcoat kit that contains little tubes of coloring agents, and get ready to play with color matching.



For your repair, first lightly sand out the gouge to prepare it, and then wash with acetone. Using unthickened and uncatalyzed gelcoat (start with a quantity sufficient to effect your entire repair once the coloring is complete), start to match your color. These little kits include some basic references for what colors have which effect, but it's mostly by eye. Add small amounts of color to approximate your actual hull color. Then, rub a small, thin bit of this uncatalyzed gelcoat on the hull adjacent to the repair, and let it flash off in about 5 minutes; this approximates what the cured color of that mix would be. (By "flash", I mean that the solvents present in the gelcoat base will evaporate out; it won't actually cure, but will become sort of dry to the touch.)

Decide how, or if, you need to futher modify the color and repeat this process until you end up with something that matches closely. I am no gelcoating expert, but I have found this technique to work very effectively. In the photo below, I required 5 subsequent coloring steps to acheive a decent match with the beige gelcoat on this boat. I suspect you'll likely be using mostly yellow, perhaps brown. But add very small amounts of colorant at a time! It won't take a ton of color to match an aged white hull, but it will require some colorant.



When you are satisfied with the color, go ahead and catalyze your gelcoat, and then thicken it to a putty consistency with cabosil. Apply this thickened mixture into the crack like a filler. Overfill it somewhat, since gelcoat shrinks as it cures. Your gouge sounds so shallow that one application should do it.

Gelcoat needs to be air inhibited to cure, so you can either tightly tape plastic over the repair, add a wax to the gelcoat, or spray some PVA liquid on the exposed repair. When the gelcoat is cured, wetsand and buff to blend it in with the surrounding hull. (PVA, if you use it, washes away with water.)

Good luck!

[David VanDenburgh]

Great replies all. Thank you! Just the kind of information I was hoping for.

[fusto]

...and get ready to play with color matching.

When the fiberglassers/painters at my yard are color matching gelcoat they put the little dabs of colored gelcoat on some clear cellophane packing tape and then tape it to the hull.
They say that it gets rid of any shadows in your blob of gelcoat and makes it easier to match to the hull color.

When he showed me, it seemed to make a difference, but then I'm also just a mechanic.
:-)

Your mileage may vary.

[bcooke]

...but then I'm also just a mechanic...

Grrrrr.... but I am guessing you already know how I feel about that statement. Average people will never know how often that phrase is used and how much pain it causes... I have a whole tirade devoted to just that comment but I will spare you all :-)

...for now.

Nothing to say on the topic at hand. Me and colors don't go together very well so I have always shied away from what they tell me is the tricky operation of color matching.

-Britton

[Tim]

...but then I'm also just a mechanic...

Grrrrr.... but I am guessing you already know how I feel about that statement. Average people will never know how often that phrase is used and how much pain it causes... I have a whole tirade devoted to just that comment but I will spare you all :-)

...for now.

Down, boy, down!

[Rachel]

I've only made a few, minor gelcoat repairs, so take this with that in mind.

I planned to make a few repairs on my "white" boat (Monty 17 I used to own). The boat was fairly oxidized, so I compounded it - luckily it was before I made the repairs, because boy, did the color ever change! So if your hull is at all oxidized, you might want to rub/buff a bit first, to make sure you're matching the "real" gelcoat color.

Rachel

[fusto]

...but then I'm also just a mechanic...

Actually, to be totally accurate I'm the Lead mechanic.
ooh management! (even worse)

Sorry if I got your dander up.

I was being facetious.
Didnt you see the... :-)

[bcooke]

So was I

;-)

-Britton

[Ceasar Choppy]

FWIW, a teeny tiny little dab of the coloring agent is all you need... especially if you are shading white. Don't ask me how I know this.