Was the initial prep for bottom paint done correctly?

06Rinker270

Hey Everyone,

Looking at the bottom paint that has chipped away and exposed the white hull I can see that some of it still has a glossy feel and does not feel sanded.  My concern is that this is not done correctly and will blister.  I have a few pictures but not sure you can tell.  The white is not rough but smooth. 

MarkB

That looks like it's already been painted over with something black (see where flakes have previously come off, where there is black coating over).  What is that?

There's no doubt, the manufacturer (Interlux) recommends a rough surface for barrier coat. They recommended that we sand blast our bottom. We did not remove all the gelcoat, just roughed up the surface and cleaned the mold release agent off.

After that 4 coats of Interprotect Barrier Coat and 2 coats of Micron CSC (VC17 is also good).

I had to raise my coating as the water line was going above it towards the back. They did not sand the raise properly and it basically all flaked off in 1 year. Not the original bottom, just the raise (about 1 or 2"). I had someone else redo it. They stripped the old paint, sanded properly and reapplied. I'm in my 3rd year, and the undercoat is sticking like crap on a cottontail. I haven't even had to touch up really, just in places where we knicked the anti-fouling during haul out.

06Rinker270

My concern is that I need to strip it all off and have it done properly.  I also need to raise the line as well, getting some yellowing up front.

Has anyone had issues with Rinkers blistering or know if they had issues in the past?

Stodge

Some bottom paints are ablative and made to fall off over the course of the season.  You may have had a mix of bottom paint types applied.  I'd see about having the hull soda blasted and your choice of bottom paint applied.

MarkB

Stodge, that is for the anti-fouling, not the barrier coat. The barrier coats are never made to fall off - they are the waterproof barrier to prevent blistering from osmosis. Anti-fouling, yes, some technologies like VC17 are ablative.

06Rinker - when I had to fix my raise, we had to strip the old raise off, and even some of the original bottom to be able to blend the new barrier paint in properly. There are many companies that will offer to strip and repaint the bottom, it's a fairly common practice, especially when people don't know what is on their bottom paint and would like to start with a clean sheet. I wouldn't worry about it too much.

Every boat is at risk of osmotic blistering. But I can tell you my gelcoat guy (who is always busy with gelcoat, fibreglass and paint) indicates that he rarely sees issues with Rinkers.  The risk is generally low.  I believe the gelcoat technology has improved in the last few years, and that osmotic blistering is less of an issue today.

I know there is risk, and you may be concerned, but if it were my boat, I'd probably just leave the job for the fall. It will probably take you a month to find a good person, get a quote and get them booked anyhow.

06Rinker270

Thank you guys for the advice and opinions.  

I am currently on a lift but I am going to a wet slip here in early August.  As you all agree the bottom needs something before it goes in.  Do you think its ok to just sand and repaint(which I will do myself) or should I do the barrier coat.  

@Alswagg Do I remove all the bottom paint by sanding or do I do a chemical strip.

Handymans342

All of that bottom paint needs to come off and the bottom prepped properly for paint. Cost me 4600 to do my boat from scratch because it had never been painted.

MarkB

In my opinion I would do the barrier coat, if anything to put your mind at ease and when you sell the boat, it's a good selling point.

Handymans342

OK, they sanded the bottom (all day job) 2 barrier coats and 2 bottom coats. 

Black_Diamond

I was just quoted $3850 to sand blast off my old bottom paint, 4 coats of barrier paint, 1 coat of VC-17.  

MarkB

BD - get 2 coats of VC 17.

What barrier paint are they using?

MarkB

I paid $3500 Canadian, about $3000 US to sandblast a new bottom, apply 4 coats of Interprotect and 2 coats of micron CSC on my 260EC.  The guys up here in Canada are a little more expensive, due to probably less turn over.

Black_Diamond

I was thinking 2 coats of the VC-17 too. I assume they are using the interlux for barrier coat. Good question though. 

06Rinker270

I called the POs marina(South River Marina for those of you local to me) and they said they have records of the boat being sanded down, primed and painted.  This was more than 10 years ago, boat kept on lift, which is why the paint is flaking off.  My mechanic had a look and told me a proper standing and repaint would be just fine, no need to barrier coat and sand blast.  Thoughts?

MarkB

06Rinker270 - what are you looking to achieve?  A top coat of anti-fouling paint is not an anti-barrier.  If you aren't worried about osmotic blistering, then I think you have your answer.  Osmotic blistering is always a risk in my eyes, especially at the water line.  If the boat is kept in water all the time, then maybe a barrier coat is a good idea. If it spends very little time in the water, and is on a lift when it isn't, then maybe you can skip that step.

06Rinker270

@Alswagg What do you use for prep wash?

06Rinker270

@AlswaggThanks for the info.  Do you think it be good for me to follow these steps?  Sand with 80 grit, get rid of all shiny spots and paint build up, prep wash, 2 coats of Petit or interlux like you said.

06Rinker270

Good to know thank you.  Last question...would I use the prep wash in my case as I am repainting?  vs adding paint for the first time.

06Rinker270

Is this the prep wash?

06Rinker270

I really appreciate all the advice.