Monday, January 4, 2010

Bottom Paint

After much sanding, filling, fairing, the bottom was finally ready for coating!
In total, eleven holes from previous thru-hulls, instruments, etc. were repaired and glassed over. Three were left, and a few more will be added when required.
The hull was vacuumed then wiped with Awlgrip surface cleaner TO115 with wax and grease remover using the two cloth method (one wet, one dry) for wipe down. Its a medium fast evaporating solvent that gives you more time than fast evaporating types to do the wipe down. This was then followed by the same two cloth method using Awlgrip T0008 fast evaporating solvent just before painting. It is a mild cleaner that removes hand oils and light contaminants.
Jon (our coatings and detail tech) was kind enough to come in and strike the line, laying the 3/4" fine-line tape on the hull and then 1-1/2" blue tape above and over half of the fine-line to give us more room to over brush the line. He gave us some pointers on rolling out the paint and off we went.
Two coats of two part Pettit Protect epoxy barrier coat was applied by roller. No sanding was done between coats, its not required if you follow the dry and recoat times on the can. It has a long recoat time before sanding is required so its easy to schedule and make work.
The following day the entire hull was sanded with 80 grit and wiped with the T0008 in preparation for the antifouling paint. We could have tried to apply the antifouling in the allotted time without having to sand, but the margins allowed for recoating between the barrier coat and the antifouling paint are much shorter than the margins for the barrier coat. Its very temperature and time dependent and if you get it wrong then the coating fails after its been in the water for a few months, just falls of the barrier coat in large flakes. Hulls don't dry evenly, and the time between starting at the bow and finishing at the stern must be taken into consideration.Yup, we know this from experience. We have used Pettit for all but a few of the bottoms we have done in our yard for the past ten years. We got bit twice in the first year with the antifouling flaking off the barrier coat and made it a company policy to sand between the barrier coat and the antifouling coat and have never had a problem since. Two coats of Pettit Trinidad SR was applied by roller. The stuff is 76% cuprous oxide and has anti-slime agents. Two more coats will be applied before the boat heads for the ocean. If applied more than two months before launching the Pettit rep recommended misting or spraying  the hull with water once a month to keep the paint active.
After painting we sat there and just stared at the hull for a while and grinned.......two years we've been waiting to see paint on the hull.......two long years! 

Jon applies the fine-line tape

Pettit Protect Barrier Coat

Pettit Trinidad SR antifouling coat


Anonymous said...

Keep posting stuff like this i really like it

Anonymous said...

Your blog keeps getting better and better! Your older articles are not as good as newer ones you have a lot more creativity and originality now keep it up!

Don said...

Will do, glad you like it. :-)

Don said...

Thank you for the kind comments :-)