Antifoul Removal - Using Stripper

[gandalf]

As with most jobs, the further you delve into things the more problems you find. All the antifouling was removed to reveal thousands of tiny blisters under the gelcoat. Sanding off the gelcoat showed them to be about 1-1.5 mm deep, the glass below that appearing to be sound. The task of grinding out each blister (did I say thousands - probably closer to a million overall) and then filling and fairing, has led to professional advice to plane the hull, replace the thickness of glass removed and apply barrier coating before antifouling.

So, as no planers are operating locally the budget has to extend to buying a Gelplane,, possibly to be resold after the job's completed. So if anyone needs a near-new Gelplane......watch this space!

[skipmac]

Had the same problem and considered buying a gel-plane myself. Fortunately found a guy that contracts to a number of different boat yards in my area and was will to travel to me.

I was very happy with the results and highly recommend it over sanding or sand blasting. Of course he does it all the time so has the procedure down pat but only took him about 4 hours of actual cutting to do my 42' boat.

[cburger]

Before you go through all the trouble of planning the hull you need to make sure that the the little holes you describe are actually blisters. Very often "Old" surface gelcoat below the water line will take on the appearance of blisters. The inexperienced in their zeal can quite often create way more work than is required and potentially do much damage to the hull by planing away at the hull. I did a Cape Dory bottom job two years ago, after bead blasting the bottom the gelcoat surface had millions of tiny holes covering the hull, just as you are describing, (These were not blisters). Serious blisters are usually larger than what you are describing and are or will weep water that has been obsorbed. To test, get a Dremel tool with a small bit and go around the boat and without going very deep, maybe 2mm at best enlarge a couple of these holes, 2mm should be more than enough, to see if you can get them to start weeping water. Additionally you want to have the hull moisture metered by an "Experienced professional" to dertermine if the hull is in fact water saturated. If in fact your issue does not turn out to be a blister problem and the remaining gelcoatis still bonded well with the substrate then it is a simple matter of washing the hull very well with water (No soap) and a green scotch brite pad, followed by a good acetone wipe down with lots of clean rags. Next step is the correct number of coats with a quality barrier coat followed by the bottom paint of choice. Knowledge is definately power with what you are trying to do. A good bottom job is challanging enough without adding more headaches like blisters you may no actually have to the equation.

Good Luck!

[gandalf]

Thanks, your point is taken.However they definitely are blisters, weeping etc but very shallow. My original suspicion was that they were osmotic blisters but several onlookers suggested they may just be paint blisters. My time-consuming process of gradually removing all the antifouling to expose the gelcoat, and then sanding some of the gelcoat to expose bare glass, has confirmed those suspicions. Planing and a washing/drying programme before reglassing and applying an epoxy barrier are on the agenda.

Don't worry, I do not have a masochistic nature! I love my boat and enjoy working on it but have no desire to do more work than necessary, let alone spending money that could be better spent elsewhere.

[Rustic Charm]

Hey everyone, being its mid 2014, has anyone tried the new product called DeFoul? It's a new revolutionary stripper for anti foul, so the web page says.

DeFOUL – Anti-Fouling Paint Remover

[richard1970]

We've stripped several boats in yards that don't allow dry blasting. With the Dustless Blasting system, it mixes water in with the sand, so that the waste drops straight down and you don't have the dust cloud.