Scott: i recommend that you follow the antifouling product's prep recommendations. this includes cleaning the bottom before sanding to assure no waxes, or other slippery stuff, are present. i use Interluxe's Solvent 202 to clean the bottom of the new boats _before_ sanding (this is important) and again after just before painting. this stuff is so good it can't be sold/used in CA. WEAR an organics respirator, glove up, wear eye protection (if you wear glasses use a old pair, or eye protection over the glasses, as this stuff can mess up plastic lenses) and invest in a disposable 'bunny suit' when using this stuff. as Robbin stated fixing the scratches that do not go through the gel coat is better than not. ultimately up to you. if the scratches go into the fiberglass i recommend repair before painting. here is the link to West System's blister repair manual (a PDF file) - http://www.westsystem.com/ss/assets/howto-pub2/Gelcoat%20Blisters%20Diagnosi... i'm sending you good karma vibes as you prepare to sand and paint you boat ... lapstrake is great but doing bottom work you will begin to wish the boat was smooth (only during the project; once done you will again be happy the boat is lapstrake and not 'Clorox bottle flat'). the centerboard pin should not be held in place with silicone. if it is this was done by a prior owner. DON'T use silicone on your boat. the only, ONLY, exception is lexan cabin windows. Jerry used a thickened mix of resin to hold the pin in place. can also be done with 3M 4200. as already discussed the pin goes through the centerboard. i've attached a picture that shows the 'parts' of an M15, M17, M23 and S17 centerboard (all have the same essential design just differing sizes based on year of build). :: Dave Scobie --- On Wed, 5/8/13, Scott Larson <salarson2@comcast.net> wrote:
I am in the process of getting my newly acquired Montgomery 15 ready for bottom paint. Since it will be sitting at a mooring, I think it will be prudent to prep it with an epoxy barrier paint and then paint with my bottom paint of choice. I have found a product that seems to get the hull nice and clean. It is this highly caustic stuff, but tends to get all the grub and stains off the hull. I will be using a new product by West Marine (made by Petit). They claim you should prepare the hull using this stuff that costs over 30.00 a quart to remove residual mold release agent. I suppose it is possible that there may still be some mold release agent on a 30 YO hull. But even if there is, I have read that it can be removed with warm water and a sponge. Does anyone have any feedback on this matter?
As for painting the bottom with barrier coat, is there any reason why I cannot just paint over the small scratches with the barrier coat without filling them? Also, there are some areas with small blisters, about 1-2 mm. What should I do with those?
Also, a few of the scratches seem to reveal green gelcoat beneath the white gelcoat. Is it possible that the boat was originally given a coat of green gelcoat beneath the white gelcoat? This might actually make sense if the entire mold were sprayed with white up to the sheerstrake first, then had the entire inside of the mold sprayed up to the sheerline with green gelcoat to get the green stripe. The other possibility is that the hull was originally green and it was painted or given a new gelcoat up to the sheerstrake. If that were the case, whoever did it, did a pretty good job of it.
As for the centerboard, the pin is covered with what appears to be a silicone marine sealant on each side. Should I just leave that alone and hope for the best? Does the centerboard have a hook at the end where it attaches to the pin? In that case held in by the force of gravity? From the pictures of John Harris' repair, it appears that he re-set the pin before putting the board back in.
Any insight would be great!
Scott Larson