First time bottom paint help

[Anthonym2]

Hello All

I'm getting ready to put bottom paint on my fiberglass boat for the first time. I had it in a slip (fresh water) all last year and experienced some bubbling and what looks like faint flaking after i pressure washed in the fall.
I'm pretty handy and ive watched a couple how to videos. I already purchased paint from a local shop.

A couple things im confused on.

What kind of sand paper should i be using ? There is no existing bottom paint so i dont want to damage anything and are not sure. Does it need to be wet sanded?

Does it need primed first?

Ive seen it brushed and rolled.....does it matter?

How long should i wait to put in water after paint?

Any tips/tricks would be helpful.

Thank you!
(pictures from fall to follow)

 

[Anthonym2]

No Title

 

[ondarvr]

All of the info you need should be supplied by the paint manufacturer, follow them closely for best results.

​Gel coat doesn't normally flake off, but it can blister, normal bottom paint will not help prevent blistering, but will help prevent gunk growing on the hull if you keep it in the water.

 

[Anthonym2]

Thanks....i had a couple people look at the pictures and it looks like old paint or something....its alomst like a wax or something. I do not think its gell coat blisters as the bubbles are so thin they flake off and its not pitted underneath.

 

[ondarvr]

If it flakes off then it all needs to be removed for best results, it just depends on how long you want it to last. There are several clear products on the market that claim to rejuvenate the gel coat, they all typically fail in one way or another after a while.

 

[Old Ironmaker]

Follow the manufacturers directions, closely. They differ product to product. You will be fine brushing or rolling a small section at a time and back brushing with a wide foam brush. Maintain a wet edge always. I don't agree with everything shown on You Tube, sometimes I disagree 110%. A great chance to change the colour too.

 

[Scott Danforth]

you have blistering

you need to take care of the blistering

you then need barrier coat (many layers).

you then do ablative bottom paint (many layers)

 

[JoLin]

^^^^ This ^^^^

 

[Anthonym2]

you have blistering

you need to take care of the blistering

you then need barrier coat (many layers).

you then do ablative bottom paint (many layers)

I had several people look at this and many (including folks on this forum) did not think it was blistering, however im certainly not the expert my any means so ill take your word for it.

The bubbles are so small and they flake off easily, is sanding "taking care of the blistering"?

What is the difference between bottom paint snd barrier coat?

The manufacturer on the paint says sand with 80 grit sand paper for applying on bare fiberglass.

Thanks for the responses, i do appreciate it

 

[Scott Danforth]

So sand with 80 grit.

Sanding alone is not taking care of blisters. It is a step in taking care of blisters

Barrier coat is the sealant to keep water from blistering your hull

Bottom paint flakes off so critters dont stick too much. After 2 years, you sand the remaining bottom paint to the barrier coat and re-apply the multiple layers of bottom paint