Barrier Coat Before Bottom Paint? Yay or Nay?

[jethrosixxx]

My '78 19-6 FF has never been bottom painted and does have her share of keel scrapes.  What is the general thought of using a barrier coat prior to the bottom paint?  I've heard that the barrier coat will fill microcracks, further waterproofing the hull.  Is it worth the time and expense?

[LilRichard]

If you have breaches in the gelcoat down to bare glass, I would suggest fixing those prior to even barrier coating... but yes, a barrier coat is always a good idea before bottom paint.  It's an easy step that provides added insurance, and there is no downside other than the extra effort.

[damnitbadger]

I would go a step further and put a coat of thin epoxy on prior to the barrier coat then apply the bottom paint. Be sure to check for any blistering, sometimes they are hard to see.

[MarshMarlowe196]

What are your reasons for wanting to use bottom paint to repaint the hull?

Do you plan on leaving the boat in the water?  If yes, then barrier coat is a good idea.  If not, then you don't need barrier coat, though, as mentioned above, it wouldn't hurt anything to add it.

[Marcq]

I still can't understand why you would need a barrier coat on bare fiberglass even if it's a small spot on the hull, most bilge don't even have gelcoat in them and like everybody knows there always a small amount of water that gets in there(sometime big amount) and yet my 30 year bilge on my Aqua is not falling apart, just bare fiberglass in there  

Marc..

[damnitbadger]

Fiberglass is not waterproof! Resistant, yes. If you immerse a hull in water 24/7 you will have water intrusion into the glass it's self not to mention growth of all kinds in a salt or freshwater environment. Epoxy is much more water resistant than poly resin based gel-coat. As for your bilge, if you do not have a barrier coat or gel coat and you let water stand in your bilge for long periods you will have some degree of saturation in your hull. This increases the weight and decreases the structural integrity of your hull. Pro's will let the hull of older boats "dryout" before doing a bottom job. If you trailer your boat this is less of a concern as you are drying out every time you pull it from the water.

[REELCLIMAX]

I would do it. I paint boat bottoms when Im not at the fire house and it will prevent any blistering in the future.