A Few Thoughts On Bottom Stripping
Personally, I'm all for the grinder...with full skin (suit, gloves) and respiratory protection...and, of course, some kind of containment/disposal (Vizquene, shopvac). If a person is going to take it off abrasively, I highly recommend (if an adequate air source is available) the venerable 7" vertical polisher for the rough work and a 5 or 6" DA sander to finish off. Very fast, very clean, very smooth. We're using 40-grit here, mind you. The vertical polisher was/is long a mainstay in fiberglass and aircraft work. VERY low RPM (under 3000), very controllable and very effective. If you simply have to buy one new, Ingersol-Rand still make one and you can get it for a couple hundred bucks. I've managed to score a couple off of E-Bay for friends at less than 65.00 each, but it took a while until they came along in the listings as people who know what they have do not part with these. If nothing else, Harbor Freight is now selling a Hong's-of Taiwan knockoff for less than 40 dollars...I'm just not big on Taiwan/China/India anythings. You get what you pay for, after all.
The combination of the two above mentioned tools will easily allow a nice smooth bottom with no half-moons to fair in. Easy. Sweet!
If you are really into chemicals and do not like to grind, chemical strippers sound like a real good option. I've never used the peel-away product, mainly because of the cost, but again our man Ebb has come through for us with an answer to that problem. I will say, though, that I have seen bottoms where that stuff did not do the trick no matter how much was applied...took off a lot, but still needed sanding. God knows what kind of paint was on the two boats I am thinking of in particular, but it was tenacious.
Good old fashioned methylene-chloride based "aircraft stripper" works well, too, but you have to be careful to get a feel for how fast it will work on a particular bottom so as not to leave it on too long, and you have to be sure and rinse it VERY---VERY!---well, including scrubbing snot out of the bottom with a scotchbrite. It eats fiberglass just as readily as it eats paint if not moreso, and it tends to make a home in the surface porosity (hence the scotchbrite), waiting to wreak havoc with the adhesion of the new barrier coat and/or paint! Beware!
So much for chemicals...another option is to sandblast. Again, containment is probably a priority. I've seen some guys who do it with regularity who are very skilled and make it look easy...it really takes a careful eye and a good feel to do it well, though, and done poorly or heavy-handed it will dig holes right in there. Even with a really skilled man (figure of speech, sorry...I have absolutely no doubt that a really skilled woman...or even a really skilled hermaphrodite...could do this very well) doing it, there will be fairing to do later. I have never sandblasted a bottom before myself, but I think I could do OK as I have blasted other things plenty with a variety of media. I thought of doing this to the Triton as I do own a smallish "siphon-pot" type blaster, but figured it would take forever...the pro guy I've seen contract to do it in our yard has a rig that looks closer to a firehose!
OK...Here's the last bit. Ebb mentions powerwashing, and I should put this one in. Our yard has a VERY mean, gasoline-fired pressure washer...I have no idea how many PSI, but I am told by a co-worker that it really will take the skin right off of you. When fitted with the rotating-pulsing-jet nozzle (a shower massage for the inquisition?) it will, given enough time taken, strip an entire boat bottom of ANYTHING. We had one fellow with a 35' powerboat who actually wanted his bottom strippped this way. I'm sure it cost him dearly, but in 3 hours' time it was completely free of paint save for a few spots that needed a small bit of sanding to remove the last and most tenacious spots. If you have a really big, really mean powerwasher to deal with, you might give it a try. Wear your raingear...and your boots...and a mask (Cuprous oxide and TBT taste like crap and stain your teeth a sort of bluish color, and you will eat some if you do not have something over your mouth)...and definitely some serious eye protection.
Some amount of sanding/grinding is always going to come into play, so I will offer this thought as well. I see people all the time coming out from under the boat and Vizquene wearing respirators and tyveks...with bottom-paint-colored faces. If it is hot, you will sweat...and wet the stuff, and take it into your system. This is not good, and if you really do it good for a week or two may leave you feeling less than stellar. There is an old boat-plant trick for grinding 'glass of putting vaseline on your eyelids and below your eyes to catch the fine particulates...and you can give yourself a "barrier coat" of sorts by applying liberal quantities of vaseline to all the parts of your face not covered by your respirator or your suit's hood. You'll sweat it off after a while, but you can wash your face off with the nearest hose, dry and reapply as needed. Helps keep the yack off of your skin and hence out of your system, y'know?
OK, there's all of the commentary I could possibly chime in with on bottom stripping. Maybe even a quarter's worth!
:D
Dave
sanding it off small time
There's John down at the yard. he's taking the bottom off his project with a 2amp Porter Cable (SlickSander?), a fairly small and fairly light random orbit with the motor on top using five hole paper. There's a fitting out the side what connects to a vaccum with small diameter hose that doesn't weigh anything at all. He insisted I try it. Not bad, I'ld have to do it in small sections too!
John's boat is about 4 feet away from a highly finished frostwhite Triton. He has no plastic tarps down, and he's not scheduling sanding when the wind is up. Must be fifteen boats being worked on.
There aren't too many coats of bottom paint on his boat, but it is old, and has been out of the water awhile. He buys sheets of 24 grit peel & stick floor sander paper that he cuts into disks, and then punches the vacuum holes with a cheap punch (Harbor Freight.) Don't recognize the vacuum, it looks like a beer cooler/lunch box, and sucks 98% of the dust into its innerds. John wants to try some 16 grit. Because the hull is so hard it looks like it's been sanded with 120.
He's doing it in sections, when a piece is done he paints on some underwater highbuild epoxy, sands on that for a spell. Don't know what the floor paper costs, he's a deal on that as well. - but this is a very clean low budget bottom removal system. No chemicals and very little blue dust.:cool: