Re finishing rudders?

I found that out the hard way! I put three coats of epoxy paint on some old sun-baked EPO's and they still look like hammered hell.

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Sheet In...Max Out
www.fleet297.org
sailflatlands at gmail dot com

Now I'm screwed, look at this and tell me what went wrong, and what should I do to fix it.

I used High Bond white gel coat with wax, 2 oz styrene per pint of gel coat to thin, 4 cc of hardener, 1 tube of black pigment for gel coat. it 72 out side and sunny

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ALLEY CAT 1984 RED LINE HOBIE 18 MAGNUM
Sail # 10505 or 277

What you did wrong? - No surface prep. At a very minimum, you needed to remove the sticker and wipe it all down with acetone.
You can't just shoot the stuff over a crappy surface and expect it to look good.

Clean it up with acetone, sand it smooth and start over.

I spend 3 hours sanding with a foam block first 150 then 220. Then I spend 30 min with 2 rags and acetone wiping the whole thing down, until all I saw was white when I wiped it with a white rag. Of course I did surface prep, who sprays gel coat with out prep. I left the sticker because there were layers of gel black epoxy on top of the stickers.

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ALLEY CAT 1984 RED LINE HOBIE 18 MAGNUM
Sail # 10505 or 277

Not to hijack:



Sorry to hijack,

I have some black ones that are very stiff but feel like plastic ( have to be the Lexan right? They are old I think), and some white ones that feel like they are fiberglass which I am assuming are the racing rudders.

Resume normal operation

Also, you cant use epoxy on polyester?

Dang! I hate that! I feel a "Previous Owner" rant coming on, but I'm going to hold back

This is precisely why one should always use what the boat was made of to do the repair. I guarantee that some previous owner (PO) coated those suckers with a rattle can. Probably looked good for a couple of years for them. Then you come along and think all is right with the world and look what happened. That's a mess, but you'll get through it.

Here's what happened to me. I took on a group dagger board repair and had 12 Hobie 18 boards in the shop. 6 of them were coated with something other than gel and they did exactly what your boards did. 6 daggerboards!!! Done, do over! I called one of the owners to tell him that they would be another week due to a chemical reaction and he said, "Oh yeah, we coat them every year with spray paint." Dumb me for not catching it, but it'll never happen again.

Here's what to do: Hit em with acetone and a rag, get what you can. If some of the gel is stuck on well, hit it with some PVA and put them somewhere warm to kick solid. Then DA them with 80 grit and get past the coating, whatever it was. Don't be shy.

Then...
Fair the head where those casting scratches are with Formula 27, block with 80 G, Then block the whole thing with 120 and spray them with about 6 hot coats of gel.
PVA, wash, sand to 600 buff with 3m Perfectit 3 heavy cut.

Don't fret, they'll be beautiful!!

Look up my gelcoat video if you need some help. That's the right way to do it.

And one more thing...

Since you're going through the trouble, mix some thickened resin and fill those holes and redrill them. Those are pretty worn. It will tighten up your rudder system alot.

Hope that helps. Happy sanding!