Gelcoat Help !

[Lock]

Hey all!

Alright. I have the boat I want. Rigging and sailas are great, but the hulls need some major repairs it seems.

With your professional eyes, what will be required to get these hulls in ship shape. it appears the gelcoat is flaking off. My first impression is strip it all off as much as possible by hand before respraying it, or do I need to go further?

Please see attached photos...

Thanks all!

[cburger]

Are these spots the only ones and are they below the water line?

[Lock]

Originally Posted by cburger

Are these spots the only ones and are they below the water line?

yes. only at waterline

[delmarrey]

Myself I wouldn't bother with adding more gelcoat. It looks as if the gelcoat was put on after the build. I think I see primer.

I'd redo the whole bottom with a barrier coat epoxy. Stripping it all clean leaving any gelcoat that wants to stay then fairing it in smooth.

A couple question though. Is this an all fiberglass hull or glass over wood? And how old is the vessel?

I see a bunch more cracks showing up thru the bottom paint. Gelcoat is normally a polyester, which is porous. Once water gets behind the gelcoat it migrates especially if it's a spray-on.

Gelcoats done in a boat mold is still tacky when the glass is laid in. Spray-on gelcoats, the glass is already cured and the bond is less durable.

[Lock]

Originally Posted by delmarrey

Myself I wouldn't bother with adding more gelcoat. It looks as if the gelcoat was put on after the build. I think I see primer.

I'd redo the whole bottom with a barrier coat epoxy. Stripping it all clean leaving any gelcoat that wants to stay then fairing it in smooth.

A couple question though. Is this an all fiberglass hull or glass over wood? And how old is the vessel?

I see a bunch more cracks showing up thru the bottom paint. Gelcoat is normally a polyester, which is porous. Once water gets behind the gelcoat it migrates especially if it's a spray-on.

Gelcoats done in a boat mold is still tacky when the glass is laid in. Spray-on gelcoats, the glass is already cured and the bond is less durable.

It is a cold molded hull. Build year is 1987. It is a one off build. I was told by my broker to do the same thing. Spend the entire weekend stipping by hand, cleaning, fairing, and then have a mobile painting service come to the yard and spray it. While I am at it I might as well have them paint the entire boat, as the top deck needs paint as well.

How thick is the bottom epoxy apllied? Ball park price bottom epoxy for a 40 foot trimaran?

Thanks in advance!

[CharlieCobra]

The barrier coat needs to be a minimum of 10 mils thick when dry to be effective. That means four to five coats. It covers a pretty good area or at least, Interlux 2000E does. I can get 1.5 coats per gallon kit on a 32' sailboat bottom. I don't know if "Peel-Away" is available where you are but I just used it on a boat to take it down to Gelcoat. If the old Gelcoat needs to come off, you'll have to grind it. We did a soak time of 48 hours because the boat had hard bottom paint under ablative. It cleaned up nicely with lot's of scraping. Get some good strong lads to help and good sharp scrapers. You'll need both....

We charged 2K USD for the 32 footer. Yours would likely run closer to $3700. Prices in your area make vary...

[colemj]

We used 4 gallons of 2000E for our 40' catamaran. I would think a 40' tri would be similar. Cost was $75USD/gal and we did the work ourselves (no more difficult than bottom painting).

Mark

[delmarrey]

I don't know about prices in Germany but here is some good info about barrier coating.>>> Barrier Coating

This video is a bit over kill but you get the idea. If it were a spray-on it would be much easier but expensive. And normally it's gray color not red/brown, unless they've changed it recently.

http://www.youtube.com/watch?v=JERScAzojzI

[CharlieCobra]

Originally Posted by colemj

We used 4 gallons of 2000E for our 40' catamaran. I would think a 40' tri would be similar. Cost was $75USD/gal and we did the work ourselves (no more difficult than bottom painting).

Mark

Yep, applying barrier coat is easy. The prep is not.

[colemj]

Ah yes, you are correct - the prep is all the hard work.

Mark

[delmarrey]

One more thing about the West Systems barrier coat is it likes to run so it can't be put on too thick, that's why two coats. The first coat looks as if it's not covering so one tends to try to put it on thicker. You have to get the right amount of powder in the mix.

BTW - In the video I realized there wasn't any of the 422 powder mixed in the epoxy shown. It's a bad demo!

[Lock]

Excellent! Thanks a bunch! So 10 mils eh'? I will have a quote monday afternoon. Ill let you know how hard he hits me. The boat is on the hard in Florida right now. I'm doing all of this over Skype from Germany... tough. I really ought to be on site while its getting done. I will question him on his approach for prep and what he will use exactly for an epoxy base and how thick he plans to apply it. I'll also ask him to take pictures of when he is done prepping and one picture during each layer applied.

Will send the pix. Would like to have everyones opinion.

Thanks again!!

[Jim Cate]

G'Day Lock,

Hey, wait a minute! If this is a cold molded build, it was PROBABLY done in epoxy in the first place. If so, I question the need for a barrier coat. Our strip-planked and epoxy hull is now 20 years old and has no barrier coat... just a coat of highbuild, primer, and then fairing where needed.

And again, if it is epoxy construction, then that may not be gel-coat at all. Actually looks sorta like primer and paint... and is that a spot of microballoon bog I see?

At any rate, do be sure about what is under the outer coatings before committing
to a big repair job.

Cheers and good luck

Jim and Ann s/v Insatiable II lying Trinity Inlet, CAirns, Qld, Oz

[CharlieCobra]

No doubt. A cold molded boat doesn't need barrier coat. That's only to protect fiberglass whether polyester or vinylester.

[delmarrey]

Here is what a West Systems barrier coat should look like when done. Other marine paint suppliers also have their barrier coat. This has a little blue tint due to the blue tarp. Normally it's gray.


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