Hull Exterior Projects (Updated 1-23-03)|
1) Remove bottom paint
I elected to sand off the bottom paint because of the time of year. I might have used chemical stripper in the summer but know that it would not be effective in cold temperatures. I started by using a 4-1/2" Milwaukee angle grinder with soft pad and 36 grit paper to remove the top layers of paint, but had second thoughts when I found it to be very easy to gouge into the gel coat. Thus, I tried using the Fein 6" Random Orbital with vacuum attachment and 40 grit disks for removing the bottom paint. After some very labor intensive work and many disks later, I had second thoughts again, (There has to be an easier way!!) and purchased a Sears 7" right angle sander, a 3M 8" soft PSA pad and 36 grit PSA disks. I was very disappointed in the sander as shown below.
In the process of removing the paint, I found a fairly large area (about 12 square feet) on the starboard bow that I thought had all the gel coat removed. Actually, it is a layer of fiberglass cloth applied over the gel coat to cover some surface damage. Apparently The boat overrode the mooring hardware and has several gouges in the bottom and bootstripe area. There were some repairs made for the surface damage by adding polyester filler, then covering the repair area with cloth and resin. None of this is apparent inside and thus I don't think the damage was beyond cosmetic. There are some small blisters on the edges of the repair and I may remove the repair materials to redo it right.
This photo shows old repaired damage on the starboard bow.
2) Remove boot stripe
By December 29, 2002, I have finished removing all the bottom paint as well as the boot stripe. The bottom paint took about 40 hours of sanding and the boot stripe took about 6 hours. I found that I couldn't handle more than 3 to 4 hours per day without feeling like my arms would fall off. The bottom is generally completely covered with surface crazing in the gel coat. Had I used chemical stripper, I probably would never have been able to get it completely out. Now that I realize that, I would probably never recommend chemical stripper for a restoration project where the gel coat was likely to be crazed. Overall, the condition of the hull is good. There is a repair to be made on the bottom of the keel and the repair noted earlier to the starboard bow. There are a bunch of small gouges in the port side of the keel from an apparent earlier grounding that had been filled and didn't show through the paint, but most of them will be fine to put epoxy barrier coat over. The rudder is a different story. I found a lot of core delamination and bad repairs. I am certain that I will have to take it apart to repair the core and other problems.
Photo of removed bootstripe area.
This image shows the crazing in the gel coat. It is interesting that the boot stripe apparently protected the gel coat under it. Note also that the light green on the bottom is apparently a very old bottom paint that penetrated the gel coat.
These images show the stages of sanding and the tools I used
Equipment for this part of the project
The preferred method for removal ended up being my Milwaukee 4-1/2" right angle grinder with 36 grit disks on a soft pad to get through the thick bottom paint layers. As soon as I was close to getting through the paint, I stopped to prevent nasty digs. Style was big. I had to use the grinder at a very low angle and attack the surface while moving, and remove it from the surface while still moving. The 36 grit disks on the small grinder can tear up gel coat in a heart beat. I tried a 7" right angle sander (Sears) with 3M 8" PSA soft pad but found that with the lower RPM's, it loaded up too quickly and was really hard on my arms because of the weight. The Milwaukee grinder runs at 10,000 RPM while the 7" sander runs at 4600 RPM. The 3M pad is only rated to 3000 RPM and I found it hard to keep the PSA disks from coming off. I also tried the flexible 7" disk that comes with the Sears machine and standard 7" disks (with mounting holes in the center) but just didn't find it to do as good a job as the 4-1/2" Milwaukee. Once I was down to a thin layer of paint, I switched to my Fein 6" random orbital with attached vacuum and 40 grit disks. That did a real nice job on the bottom. For the boot stripe, I used the 6" RO exclusively, with 80 grit disks to prevent serious scratches that would be tough to remove. Overall, this (the bottom paint) was a real horrible job. I used a drop cloth and two vacuums but the material goes everywhere when you grind it with the right angle grinder. It is really amazing how much material comes off the bottom of a 38' boat!
When I started the job, I was using coveralls, goggles and a cartridge style respirator. I quickly graduated to tyvek coveralls with hood, and then I used an SAS Safety Corp. supplied air repirator with full face mask. It is available from Tool Paradise for just over $500. I couldn't be more grateful for the supplied air respirator. Since I will be painting in confined spaces and will require it for many other aspects of this project, I think it to be a good investment.
To do the sanding for the boot stripe and for other future hull projects, it is necessary to have some sort of staging to be at the right height for the work. I was always envious of the trestle staging that the guys in the boat yards used. There is even an article about building a set on the "Practical Sailor" site. I built a pair with 8 - 8' pressure treated 2 x 4's and 4 - 12' pressure treated 1 x 6's. I figure they will be good to have even after this project is done. The lumber is just enough to make them with 6 - 15" level increments. These are 30" at the base tapering to 20" on top and fold up on 1/2" galvanized hinge bolts. If you are building a pair, the angle for the miter cuts is 3 degrees. I found it easy to cut the rungs with my circular saw and Swanson quick square. I clamped the 2 x 4's together during construction, so they would fold up correctly.
Really "Cool" Trestles
3) Remove white topsides paint
By the middle of January, I have removed all the white paint on the outside of the hull. It appears that the boat was never dewaxed properly before the white paint was applied, and thus it was fairly easy to remove with 80 grit on the Fein 6" RO sander. I also removed the gold leaf cove stripe by scraping and sanding. To do that, I made a steel scraper with a cross section like the cove indentation. Even so, the gold was kind of a pain to remove since the cross section of the groove is not very constant. In the process of removing the white paint, I found a lot of scrapes, digs, chips, gouges etcetera. Every docking sin ever committed shows up big time when you spend so much time "up close and personal" with the hull. During the process, I also scraped and sanded the hull-deck joint that had been covered by the toe rails and taffrail. Fortunately, the process only uncovered one major "gonk" that will need some glass fabric in the repair. The majority of the digs can be filled with thickened epoxy.
Photo of 8" port side nasty "ouch".
I then started to remove the white paint from the deck and coach roof. This has presented several problems. The first became obvious when I removed paint from a test area on the coach roof. After removing the paint, I dewaxed with acetone, lacquer thinner and finally TO-115 Awl-Prep Plus Wax and Grease Remover. Incidentally, I found a local source for U.S. Paint products (as well as other fiberglassing and painting supplies) that offers very reasonable prices. It is www.compositesone.com. Then I tried sanding to see what the surface was like. I found that the surface has a glaze like ceramic tile. The only way I was successful in breaking through the glaze, was with my belt sander or right angle sander. The Fein RO with even 40 grit paper, did nothing but buff the surface. Obviously, if I use a very aggressive device to break the glaze, I'd never get the surface fair again. An additional complication is that the gel coat is completely crazed. The gel coat is only about .015" thick and the crazing seems to stop at the first mat layer. However, I don't know if the epoxy primer will let the crazing resurface. Presently, I am waiting for a US Paint rep to take a look at it and offer advice.
An additional complication is in the non-skid deck surface. The original non-skid is a very deep diamond check pattern that is worn in several places and damaged in several other places. It has also been painted, further rendering it difficult to address. I have elected to sand it down to the bottom of the diamonds and then renew it with one part polyurethane paint mixed with non-skid grit. There are three main methods with their respective proponents' commentaries for repairing non-skid: repair the original (by making a small mold from the existing deck) versus painting with added grit, versus bonding special non-skid mat to the deck. Although I am sure the mat approach could look very nice, I personally think the paint and grit is a more practical approach. The restoration of the original pattern is not really an option because of the extent of required repairs and the fact that it has been painted and is quite crazed. Because of the volume of material to be removed, I will likely use a belt sander on most non-skid patterned surfaces to get close to the required depth. This surface has an advantage for such aggressive removal tools in that I can see clearly when I am getting close to the final cut depth and non-skid has a tendency to hide minor surface fairing flaws.
The last complication that is a temporary problem, is the weather. We have had an extremely cold January. (The enclosure has no heat source other than the sun.) We have also been having gale force winds nearly every week since November. The wind tends to be more annoying than a deterent since it is pretty well blocked by the enclosure. I am actually surprised that the enclosure is holding together so well for all this wind. Although it is usually quite comfortable to work in the enclosure during sunny days, the temperatures have been very close to freezing. It is difficult to dewax and clean in this weather as I can't use water spray to check the surface for contaminents. I won't be able to try a paint adhesion test until the temps are consistently above 40 to apply some sample primer.
4) Pressure wash inside and out
I actually took this one out of sequence a little to take advantage of a warm weather lull around New Year's Day. With the weather forecast to be above freezing (even at night) for about three days, I pressure washed on December 31st. I covered all the inside and outside surfaces with detergent and allowed a little time for soaking. I did some scrubbing with a brush but primarily just started cleaning. I found that very little was removed from the exterior but the interior benefitted nicely. The pressure washer removed a lot of the paint (but not all) from inside the cockpit lockers, main salon and the hanging lockers. There gets to be so much debris flying around that you have to pay attention to what is cleaned and what isn't. I was not using the supplied air repirator and found that my goggles were so fogged up that it was difficult to work. In hindsight, it might have been a good idea to use the supplied air just to have better vision. Of course, all the crud ends up in the bilge, which fills quickly with a powerful washer. The bilge and sump have 1/2" holes drilled at the bottom for drainage, that obviously would never keep up. The bilge however, has a 1-3/8" hole leftover from the knot meter about 20" up from the bottom of the keel. That hole generally allowed drainage without clogging. After I finished, I had to keep clearing the small holes to drain the hull completely. I installed a fan inside the boat to dry it out over the next several days, then vacuumed it completely to remove all the paint chips and crud. I found that pressure washing is a great start but does not get the surface clean enough to even paint the inside. When this hull was built, I don't think they were using finishing resin for the last layup and thus a lot of stuff "stuck" to the surface later. It does clean up with acetone or MEK.
5) Dewax fiberglass with acetone (or MEK) and Awl Prep Plus
6) Grind out and fill gouges and dings
7) Repair keel damage and hull core holes
8) Sand entire hull with 80 - 120 - 220 grit
9) Apply 2 to 3 coats Epoxy Primer