David, I used that Citrustrip and found it is sensitive to the humidity. Dry days require about 25-30 minutes to soften two layers of bottom paint. Humid days can take as long as 40 minutes. If you time it right by testing a small section the paint will skive off like butter with a blunt putty knife with the blade edges rounded to match the radius of the corners of the planks in the hull. I was also able to use a plastic putty knife on most of it so damaging the gelcoat was not an issue. If you wait too long the stuff gets hard again. When I applied the stripper I loaded the brush and made one pass in one direction with each 3 inch brush load. That seemed to work the best. If you try to stretch out the coverage the stuff will not work nearly as well. Buy at least a gallon to get yourself started on the 15, it will be cheaper than buying three quarts, one at a time. Tom B On Sun, Apr 12, 2015 at 8:07 PM, David Grah via montgomery_boats < montgomery_boats@mailman.xmission.com> wrote:
I'm planning to refinish the bottom of my Montgomery 15 soon and have no experience doing such a thing. I wondered if the group had any comments or suggestions on my planned approach. The boat has several coats of blue ablative bottom paint on it now. They look bad. They are faded and the upper edge of the bottom pain doesn't follow the waterline very well on the starboard side.The boat probably won't be in the water for more than a week at a time for as long as I own it and is usually in fresh water when it is in the water. The hull is white with a blue stripe at the top.
I plan to mount 4 - 4 inch by 4 inch posts, 8 foot long, in my garage. The bottoms of the posts will rest on the garage slab and the tops will be bolted or screwed to the joists in the garage. I will brace the joists with diagonal 2 inch by 4 inch to the garage walls (these 2 by 4's are along the bottom of the joists to the plate at the top of the wall). The posts will support the boat and the joists will keep the posts vertical. If things go right there will be very little load on the joists.
I'll nail 3/4 inch plywood squares to the tops of the posts and cut groves in the edges to run 1/8 inch cables. I'll move the boat on the trailer into the garage and jack the trailer up a few inches and put it on blocks. I will attach 1/8 inch cables to the back unused holes where the shrouds attach at the edge of the boat and to the cleats on either side at the stern of the boat and loop the cables over the tops of the posts and clamp them.Then I would lower and remove the trailer. When working on the boat, I would place "kickers" under the lip at the hull to deck joint on the side I am working on to lessen the changes that the boat would roll toward me if it came down for some reason. I would also put blocks under the keel. I would use Citristrip stripping gel to remove most of the bottom paint. I have tested it after it was recommended in this group and found it works well. Depending how hard I scrape it can take off some of the gel coat under the bottom paint as well. I'd wipe the bottom with paint thinner and sand it with 60 grit sandpaper to remove most of the remaining blue bottom paint residue. I'd wipe it down with acetone and then sand again with 220 grit sandpaper, probably wet, and wipe with acetone again. I think I will be left with white gel coat over the bottom stained slightly blue. I'd brush on two coats of off-white Interlux Brightside one-part paint up to about 1/4 inch above the top of the old bottom paint and then add a two coat red stripe about 4 inches wide to cover the uneven top of the current bottom paint on the starboard side. I figure the new Interlux won't match the gelcoat so need something to cover this transition. The edge of where the current bottom paint is would always be within the red strip by at least an inch. I'd put the trailer back under the boat and jack it up to take the weight of the posts and the cables, then lower the trailer and take the boat out of the garage and hopefully be done. Does this seem workable? Anything I should plan to do differently? Thanks!
David GrahBishop CaliforniaMontgomery 15 - Sky