Bottom Paint Shelf Life

Tug · Posted: Mon Oct 04, 2010 1:00 pm Post subject: Bottom Paint Shelf Life

Was considering buying Interlux Micron CSC and InterProtect 2000E this Fall for use next summer...would the paint and epoxy primer still be good, there is no information on what the shelf life is for these products.

Someone suggested that i use ..2 coats of All Colour Epoxy Primer for the below the water-line sealer
than.
2 coats of AmerShield Polyurethane as the bottom coat. he said he did his boat last year and it seems to be be holding up great

The only thing is that these are TopSide primers and Paints . I didn't know that you could use these below the water-line . Tug

journey on · Posted: Mon Oct 04, 2010 1:16 pm Post subject:

Tug,

First, why would you use a sealer and paint that is labeled for topside use? I don't know who makes "All Colour Epoxy Primer" and I'm not a paint chemist who can tell you the differences, but I would believe someone who said their product is for topside only. The Interlux products are made for covering/protecting the bottom of a boat. The cost can't be that much different, though bottom paint is really going up.

BTY, AmerShield Polyurethane isn't a bottom paint, but just a tough paint for topsides use, including barges and off shore platforms. Don't you want to use bottom paint over the barrier coat?

The barrier epoxy is important, if you're going to keep your boat in the water, but you might think about a cheaper bottom paint.

Second, I do know that the CSC bottom paint will last for years, as long as you seal the can carefully. I turn them upside down. Don't know about the barrier coat, but you can ask Interlux, they answered a lot of questions for me.

Boris

Sea Wolf · Posted: Mon Oct 04, 2010 1:36 pm Post subject:

Nice, thoughtful comments from Boris!

I'll only add that I favor asking the manufacturing company technical specialists any time questions arise about a product.

These people are paid to be helpful and know their products.

Sometimes their insights can be all important, saving time, money, and headaches!

Another thought: storing the can upside down is important, but be sure and do it in a cool, dry place! I had one heck of a time removing about a quart of left-over bottom paint off the floor of my RV Barn that the 110 degree Redding summer heat pushed out of the can, even leaving the lid in place intact on the can! Laughing

I was lucky it didn't wind up in a storage box holding something important! Smile

Joe.

SEA3PO · Posted: Mon Oct 04, 2010 3:33 pm Post subject:

Two years ago I applied a fresh bottom coat on the tug.... I had some new fiberglass on the bottom and did not use a sealer..... when I pulled the tug last year all the bottom paint where the new fiberglass was had come off.... now I need to sand the entire bottom again....apply a proper barrier coat...then the bottom paint.... much more of a job than I had planned on.

I thought I could get away without that barrier coat (primer coat)....nope...the bottom paint just diden't hold well ...

Darn, Darn....double darn !

Joel
SEA3PO

JamesTXSD · Posted: Mon Oct 04, 2010 3:50 pm Post subject:

4 years ago, I did the bottom on Wild Blue. Two coats of epoxy barrier, then two coats of bottom paint. That lasted about 2 1/2 years before it was necessary to touch up the bottom. Micron CSC for the bottom paint, because it stays effective even when put on the trailer for a while. Be sure to check whatever paint you use, because some lose their effectiveness when pulled out of the water. I'll be due for another full coat of bottom paint sometime soon.

Bottom paint is absolutely necessary in our area for any boat left in the water more than 10 days or so... warm water with a high salinity, the critters and slime attach quickly.

Bottom paint is a fact of life for boats that spend more than just an occasional few days in the water. Every one of our boats have had bottom paint; it's really no big deal. Put the right stuff on the right way, then don't worry about it for a year or three. Then touch it up as necessary. To me, this is simply another bit of care the boat needs. As a side note, bottom paint doesn't mean you won't have to work to clean the bottom once in a while... the ablative stuff just means that whatever tries to stick will come off easier when you scrub or wash.

Check with the local boatyards and see what they recommend for your area.

Best wishes,
Jim B.

SEA3PO · Posted: Mon Oct 04, 2010 4:59 pm Post subject:

West Marine recommends 4 to 5 coats primer/barrier paint.... they said it builds up 4 mils per coat..... I think I will try for 2 coats....then the bottom paint....

My old bottom paint is the sluffing type...and they said I need to sand every bit of it off before applying primer.... true or more of their BS ?

Joel
SEA3PO

lloyds · Posted: Mon Oct 04, 2010 5:18 pm Post subject:

I would be inclined to believe that is very true.

JamesTXSD · Posted: Mon Oct 04, 2010 5:23 pm Post subject:

journey on · Posted: Mon Oct 04, 2010 5:23 pm Post subject:

Joel,

I'm not certain what you mean. But here's some free comments.

First, there's a difference between a primer and barrier coat.

Micron CSC can be applied directly over bare fiberglass. It does not need a primer. You do have to make sure that the laminating wax and all other greases are removed. The Micron CSC product sheet discusses that: Mircon CSC Product Sheet . Those recommendations should hold for most other bottom paints. As an example, in the early 1990's Catalina Sailboats didn't de-wax their hulls properly before painting them and the (expensive) bottom paint peeled off. Sound familiar?

A barrier coat is a waterproof coating of epoxy which (hopefully) keeps water out of the gel coat and prevents blistering. A barrier coat is not mandatory, but putting it on gives a lot of peace of mind. If this is what you need, obviously one has to get down to the gel coat to seal it. That's why most people do it when the boat is new. Some boats use Isothalpic resin, and don't need a barrier coat (it says here.)

If all you want is to have a new coat of bottom paint, just sand the paint down to a solid surface, paint or gel coat, and go from there. If you want a barrier coat, WM is right and you have to have a clean gel coat or fiberglass surface. If the boat is stored on a trailer, and for example, Journey On is, I don't believe one really needs a barrier coat. At this stage in your life, you get to make your choice.

Boris

SEA3PO · Posted: Mon Oct 04, 2010 5:45 pm Post subject:

Grumble...grumble... I think yer right....I will just have to invest into some good 80 grit and prepare for about 8 hours of sanding... I know I diden't use the CLC stuff... so I best go down to the base...and start all over.... at least I got two good seasons out of it...

This year I repainted all the outside of the tug.... put 6 coats on the britework...looks real nice...(for a working tug)

Joel
SEA3PO