Bottom scraping

[crieders]

My hull is not bad but has some bare spots and some places with lawyers of paint and others with perhaps just one layer. But it is flaking in many areas where it is layered
I would not mind taking all the loose stuff, doing a new barrier coat and new paint job
There is bicarb stripping, sanding etc
Whats the best approach, least work etc??
Thanks

[Clay Greene]

I asked our yard manager after we bought our C34 when we should think about taking off the bottom paint, and his response was, "after you finish every other job on the boat."  It is just above replacing sanitation hoses in my list of bad boat jobs.  I would only do it if it is absolutely necessary.  With what you describe, I would use a palm sander to take down the loose or flaking paint and put a new coat of paint on and forget about it.  I would only think about doing it if you see evidence of blisters. 

But if you are inclined to go down this rabbit hole, I strongly suggest that you hire someone to soda blast the old paint off.  Chemical strippers don't work well, particularly if the temperature is too cold.  Hand scraping is a misery.  The only "manual" process that works is to use a power sander and that is difficult, messy and potentially dangerous to you and your boat.  We had an inch of bottom paint left at the water line after soda blasting (the soda blasting company did not want to get too close to the waterline) and we tried strippers and scraping but the only thing that worked was using a power sander.  Even trying to be as careful as possible, we still took off some gelcoat in the process.  You have to have a really light touch.  We still hand-sanded the whole bottom at least a dozen times between prep for barrier coat and between the barrier coat layers and the bottom paint because we were trying to go for a really smooth end result. 

[Clay Greene]

One other tip I wish someone had mentioned to me before we started.  We would have saved ourselves a lot of misery with sanding the barrier coat layers if we had used a foam roller instead of even the smoothest textured roller.  I can't emphasize this enough.   There is no way to avoid "orange peel" otherwise.  We now use a foam roller for all of our bottom paint projects. 

[crieders]

good advice
Think I will just get rid of the loose stuff

[Ed Shankle]

Guess it bepends on how much loose stuff you've got. If it's a little, absolutely scrap and sand to fair the edges. If a lot, then not only does that become more time consuming, but you'll probably be doing it again next year on some other contiguous spots or new ones. If that's ok, then move the full bottom job to the bottom of the priority list. However, if you are uncertain of your barrier coat, that's a different situation.
When we first got our boat, it was in dire need of a bottom job. Layers upon layers of hard bottom paint loose and patchy. I did it with a scraper. Never again! Didn't know any better, just a rookie owner. The 2nd time I did it, a few years later, I was again getting some loose patches and also realized I should have put a new barrier coat on the first time. Used Peel Away that time. Not as simple as the promo indicates, but worked fairly well. I didn't have a huge layer of build up to work through, as I had been using ablative for a few years. A bit messy to work with though and I still had some scrapping to do. After this year's haulout, I had it done again, because I want to switch to the non copper non volatile paints, figuring that's the direction we are headed. This time however, I paid to have it blasted. Came out great, but I'll have to do the barrier again, just to provide a uniform "seal" and smooth out the orange peel from the last time. I hope after this time, taking the knowledge gained from this forum and skill from some of the hired help, I won't have to do it again. Just the bi-annual application of bottom paint.

Regards,
Ed

[Clay Greene]

I was surprised to learn when we did our bottom job that the boat did not have a barrier coat.  I checked with the dealer and he told me that Catalina did not put barrier coats on before the boats left the factory and the dealer was putting barrier coats on only by request of the owner.  I can't speak to the practice today but our 2004 C387 does not have a barrier coat either. 

So, I would not expect find one between the bottom paint and the gelcoat on the hull of a C34.  We did find a small number of very small blisters up toward the waterline that were dry so we sanded them out.  But we figured as long as we had the bottom paint off, we would put on an epoxy barrier coat (we used the Pettit product) as a protectant against water absorption and as a primer for the bottom paint.  I'm glad we did it but I would never want to do it again.

[Noah]

In a case of just "some areas" of flakey paint, I would just sand, fair and repaint those areas. No barriar coat needed if you are not through the gel coat. If you want a racing bottom then blast, barrier coat, and foam roll or spray new paint. Regarding blisters; unless you have a severe blister problem (large bisters, or many over numerous areas all over the bottom) I would just treat them individually, to stay on top of them. Pop them, grind, dry them out thoughly (very omportant),  feather spot, epoxy fill, sand flush, and then apply bottom paint over. I would NOT go down the road of removing mass areas (or all) paint and barrier coating.

[mregan]

If you decide to strip it all the way down, have someone soda blast it.  I had it done to my C-30 years ago.  It took them longer to tent off the boat than blast it.  Was completed in a day for about 1/3 of what the yard wanted to charge to sand and strip.  I want to say about $1000-1500 but can't remember exactly.  It was well worth it when I calculated the amount of materials and labor I would need if I decided to do it myself.

[Ron Hill]

Cliff : You asked about the "Best Approach" to cleaning all the paint buildup off the hull?   

My answer is to have someone else do it!!  It's well worth the cost!!