Sanded through gelcoat accidentially

[LoneGunman]

While trying to sand off bottom paint I sanded through the gelcoat in a few areas, do I need to repair the gelcoat or can I just paint over it? I am not reapplying bottom paint, Im not sure what type of paint Im going to use yet.

[alan white]

Acetone cleaning, and then a couple of coats of epoxy resin. Bearing in mind, where you didn't sand through, you haven't much more than a very thin skin of gelcoat remaining. I don't know what you used to sand the hull, but I always wet sand with 80 grit on a stick with a hose and only seek to get it smooth, leaving what bottom paint remains as added protection. Water can fall to a tarp, be collected in a shallow container downstream, and allowed to evaporate. A gentle scuffing, in other words. Once a patch of gelcoat is exposed, you might spray paint that area with a color, telling you now and later it is only skightly scuffed and leave it alone and work on other areas.
The thinner areas are insufficiently protected now, something that ought to be addressed in the near future by sanding down to remove all bottom paint and applying epoxy barrier coat everywhere below the boot top.

[LoneGunman]

Thanks for replying, I decided to sand down to the gelcoat because the previous owner left the boat in the water with no bottom paint, then after the hull was fouled he painted the bottom with bottom paint, over the fouling.

Im using an electric DA sander with 100 grit, where I went through the gel coat I was using something too aggressive to try to speed up the removal of the old bottom paint, lesson learned.

Is their a paint product I could use on the bottom that will protect the thinned areas, the two part poly urethanes like Awlgrip?

[alan white]

Yes, but they wouldn't be as good nor nearly as cheap as epoxy. Epoxy's less toxic too, is thicker, and has other uses.

[LoneGunman]

I didnt realise the epoxy barrier coat was less expensive than paint, I guess I need to do some research. Do you reccomend any certain brand of the barrier coat?

[alan white]

Ask the experts. There're no shortage of guys here who know more than me.
I do know that if you apply any brand of epoxy, you'll be in good shape, but maybe some formulations are more suitable to the task at hand.
I stick to West System out of experience making for familiarity with consistent results, but that's just me.
My guess is that there is more thought that would go into proper prepararion than any other issue, and a desired thickness you want to achieve.

[tja]

If you read the labels you will find that awgrip and most other paints are not designed to be applyed below the water line. I'm assuming that you are not planning to keep the boat in the water. Even so if it were me i would use 4 to 6 coats of Interlux 2000-2001 moisture barrier. Then apply 2 coats of Interlux VC17 and the job is done. This way your bottom is protected and if you decide to keep the boat in the water then you have antifouling protection. The nice thing about VC17 is that if you need to reapply in a few years all you have to do is wash it down with water and apply a new coat. No sanding needed and also no build up with multiple coats. Good luck, Tom.

[alan white]

http://www.discountmarinesupplies.com/Interlux_Primers-INTERLUX_INTERPROTECT_2000_SERIES.html

The above describes what tja is talking about. Looks like $65.00 a gallon.


A.

[LoneGunman]

Thanks TJA, I wont be bottom painting as the boat will always be trailered. Can the Interlux moisture barrier be used alone?

[tja]

I didn't think that you were going to leave the boat in the water. Most epoxies don't work well as a top coat as they are suseptable to uv rays. Some type of top coat is required. I seggested the VC17 because there really isn't any finish that i'm aware of that is recommended below the water line other then anti fouling paints even if your not planning to leave the boat in the water. Maybe someone else will post info on a product that i'm not familiar with. I've painted dozens of boats below the water line with Imron with good results as long as they aren't left in the water more then a day or so. I still think for long term use VC17 is the way to go. Good luck. Tom.

[alan white]

The top coat is crucial to protect from UV rays, but if trailered, almost any decent single-part urethane paint will do (porch and deck enamal, $25 a gallon). Would last a few years with touch-up.
And if you want a nice hard, glossy job, one that lasts longer, keep spending, right up to Awlgrip at six to ten times as much.
The epoxy is what's doing the work, the paint is just giving it some shade.

[tja]

I forgot to mention use the gray 2000/ 2001 The white doesn't roll on as nice as the gray. I also use one inch x six inch sponge rollers from Home Depot. 4 to six coats. If it is nice and warm in your shop or outside you can apply one coat in the morning and one in the afternoon. If temp isn't 70 or above let each coat dry over night. You can go up to two weeks between coats without sanding. I like to scuff out any nibs between coats. It will go on smoother if you don't try to put on too heavy of coats. I like to put on just enough to cover the previous coat. Well I've said too much I guess. Again good luck. Tom.

[LoneGunman]

Thanks for all the info, I got it now.

[boatguy64]

I would recomend use the right primer for the top coat. Stick to the same brands products. If you are not comfortable doing it, I will do it for you. 772-595-1818, and BTW epoxy does NOT have UV protection. A Urathane is much better. Awl grip is a lot of $$ but you get whatr you pay for.

[the1much]

awl-grip makes a couple paints for under waterline, its used for aluminum boats,,but i wouldnt recommend it,,i use awl-grip almost entirely but wouldnt use it on bottom on a real boat lol, and if your gonna repaint, jus borrow a cup( buy) from somone close and brush it on that spot,sand and then paint

[jigerbetter]

Use a non - foulant gelcoat with wax solution fired at 2% and wax solution at 2% if you want then you can wetsand and buff to a glossy finish or just leave it
the fish dont care what it looks like anyway lol.
let dry till hazy finish. Most gelcoats come in many standard colors and if you purchace from a manufactuer cost on average 20to 30 dollars rufflyper gal.