Barrier Coat For 1970, 40-ft Sailboat With No Gelocat

[MJT]

I'm in the latter stages of a 10-year restoration of a 1970 Cheoy Lee Offshore 40. In the beginning stages, I stripped off the many many layers of old bottom paint and revealed a surface that looks like what you see in the pictures here (minus the red stuff, which is recent fairing, and the gray line, which is a layer of 2000e on the bootstripe).

I don't know what the blue stuff is, but based on the distribution, I expect it might have been fairing compound applied after a bottom job. I don't see anything that resembles an original gelcoat.

The boat has been out of water for 10 years, and under a shed. I recently had a surveyor come by to confirm that the hull is as dry as I could want.

Thus, I'm ready for barrier coating.

I'm considering Interlux 2000e, perhaps 8 coats. However, the gray paint you see on the bootstripe is one coat of 2000e, and I found that it sands off quite easily. I'm now thinking that I might start with a few coats of West System epoxy, then follow with 5 coats of 2000e.

Any insight or advice would be much appreciate. This site is an invaluable resource, so thank you in advance.

 

[Blueknarr]

Ten years. The rainbow is almost touching down. Good on ya for sticking it out.

Pure undiluted epoxy is far more effective at resisting osmotic pressure than epoxy diluted into paint. I recumend a few coats of pure then epoxy primer followed by anti-fouling.

Don't be put off by the failure of the 2000e bootstripe. It is an epoxy primer and was never intended to be a final top coat. All epoxy products inherently have minimal UV resistance. All epoxy primers should be overcoated within days. I'm surprised there was any left after a decade of UV degradation.

Soldier on.

 

[MJT]

Blueknarr, Without any advice I would have proceeded much like you propose, but the peace of mind that comes along with a knowledgable second opinion is priceless. I will post updates in this thread as I proceed.
Much thanks and respect, MJT

 

[ondarvr]

As mentioned, straight epoxy is what will serve you best.

Use a low viscosity formula, but not one of the thinned penetrating versions.

 

[MARKALFREDSTEELE]

I'm in the latter stages of a 10-year restoration of a 1970 Cheoy Lee Offshore 40. In the beginning stages, I stripped off the many many layers of old bottom paint and revealed a surface that looks like what you see in the pictures here (minus the red stuff, which is recent fairing, and the gray line, which is a layer of 2000e on the bootstripe).
I don't know what the blue stuff is, but based on the distribution, I expect it might have been fairing compound applied after a bottom job. I don't see anything that resembles an original gelcoat.
The boat has been out of water for 10 years, and under a shed. I recently had a surveyor come by to confirm that the hull is as dry as I could want.
Thus, I'm ready for barrier coating.
I'm considering Interlux 2000e, perhaps 8 coats. However, the gray paint you see on the bootstripe is one coat of 2000e, and I found that it sands off quite easily. I'm now thinking that I might start with a few coats of West System epoxy, then follow with 5 coats of 2000e.
Any insight or advice would be much appreciate. This site is an invaluable resource, so thank you in advance.
VENTURE HULLS CANADA says :
Try a relatively new Barrier Coat from a Company called SPRAY CORE . 1500 or 1800 , from what I know about Resin Formulations , this stuff , while a
tad pricey , has the potential to outperform what's currently available for either Commercial or Recreational Vessel Owners.
You have to Google it , and find a nearby supplier , I'm in Canada , so I can help , but you have to do the legwork. The S.C. 1500 or 1800 is sold via an
American Distributor : FASTENAL .
As an Aero Engineer , the Interlux , or trace Interlux , that remains on your exterior , should , prior to applying a Barrier Coat , be lightly sand blasted away.
It willprevent any good bond , if you don't . The best cheap way to do this yourself is to get a small portable silica sand air blaster , any automotive garage
should be able to tell you where they got thiers , buy one , and blast away all traces of the Interlux . " ABLATIVE " means that it's designed to fall away
with use. You don't want your Barrier Coat to peel off just because you didn't prep properly !!!

 

[Howlandwoodworks]

MJT,
I think your cautious attitude is best. Contact the dealers and or manufacturer by email first, ask for information on applications from tech/rep, they should send you some kind of technically sheets, study specific, then call and ask for clarification for any questions you might have. Tell them the process as you understand it, wait for feedback. Read the instruction on the containers thoroughly.
First Rule is Break No Rules for this point forward in applying any finish or coating to your projects surfaces.
Some of the main information/parameters you will need know before starting are compatibility, humidity levels +- of area that you are applying finish, also temperature +-, avoid dewpoint surface temperature, viscosity of product before application, wet film thickness for each coat, drying time to recoat, sandpaper grit# between coats if need, and hours or the amount of UV exposure it can tolerate, drying time to touch and usage.
I would suggest get a viscosity cup to measure thickness of material before applying and a wet film thickness gauge to see how much you have applying. Spraying the finish will require a lower viscosity number or a thinner material and takes a higher skill level to apply than roller and brush. You can lose up to 30% of your material into the air spraying if you don't know how to setup the spray gun adjustments and it may not be recommended that you spray it in the first place.
Follow all safety instructions. The particle use of a respiratory has shown to have no effect in prevent the harmful side effects from working with solvents base products. A solvent will breakdown matter/living tissue into a mush/liquid, when the solvent evaporate off and the matter/tissue solidifies into a solid, it will not be the same as before, like your DNA, brain tissue, etc. Your only safety check/alarm system would be your sense of smell. Respiratory cartridges do not last very long. Fresh air systems are best. Keep a dairy of your mood for three days after using any solvent base produce.
Probably not the straight forward answer you were looking for but I hope this helps in some way.
John

 

[gonzo]

I have been very happy with these products:
Boat Bottom Paint by Sea Hawk Paints - Premium Anti-Fouling & Ablative Marine Coatings https://www.seahawkpaints.com/product/tuff-stuff-low-voc-high-build-epoxy-primer/

 

[MJT]

Thanks everyone for your thoughtful and knowledgeable input.

 

[Steve W]

Im a bit late to the party it seems but I agree with the others who suggest using a few coats of 100% solids epoxy first before applying the " barrier coat". What folks tend to forget is that international paint recommend this also whenever the gelcoat has been compromised such as when doing a repair. They want you to used epiglass epoxy but that is just because that is also under the same company umbrella. Any good quality 100% solids product will do. The only time you would go straight to the 2000e is over an existing gelcoated surface in good shape.

Steve.

 

[Chuck Losness]

Well this is what worked for me. My gulfstar 37 was covered with blisters when I bought it in 2004. In January 2006 I went to Mexico and hauled the boat in San Carlos in May. Popped every blister and left the boat to dry out in the hot summer sun. Came back in November. Flew one of the top boat repair guys in Dana Point down to do the blister repair. After going over the hull we decided to remove the gelcoat and had it sandblasted off. Found lots of voids/air bubbles in the mat. Many were still wet. Opened everything up and filled all of the voids with cloth and epoxy. The last layer was epoxy thickened with cabosil applied over the entire hull. This was about 1/16" thick. Used 5 gallons of West System and 3 or 4 lbs of cabosil. No barrier coats were applied over the epoxy. And no more blisters.

IMHO I think that barrier coats are worthless. They are nothing more that a thin layer paint that is easily breached and can be sanded off with aggressive bottom cleaning.