It’s been a busy week here at Svendsen’s, the bulk of the heavy lifting is done, and now I’m at the other end of the project – waiting for the sun to warm up the air sufficiently to continue rolling on bottom paint and roll-and-tip the transom paint.
The blister repairs have proceeded normally, grind out with Dremel, tape off the divot, apply fairing, sand with the roloc to knock down the fairing compound, remove tape, and then the remaining small square of fairing is quickly brought down to be fair with the hull using the Makita random orbital sander.
Blister divots ground through to the underlying polyester fairing compound, then surrounded with 3M green tape. The tape minimizes final sanding as the only part I want to sand is the divot repair, not the surrounding hard epoxy bottom paint.
One approach to fairing in the divots is to smear the epoxy and microballoons fairing compound over the divot with a putty knife, as this saves all the time it takes to put on and take off the one and a half rolls of green tape I went through when applying the masking. The downside of not taping the holes is there is a lot more sanding to do to get the hull shape back to what it was before the fairing was applied. As Joakim pointed out to me a long time ago, it’s much easier to put on and take off tape than it is to sand.
More green squares on the port side of the keel…
And finally all the little green squares are in place, ready for fairing to be squashed into the divots.
After the tape is on it’s an easy job to use a 1″ putty knife to press in the epoxy and microballoons, then wait 12 hours for the material to harden. The tape also handles issues with shrinkage – the fairing is a plastic and shrinks slightly as part of the curing process. It’s no fun to lay down the fairing flush with the hull surface only to have all the repairs then dishpan and shrink to be no longer flush with the hull (if that happens, you get to apply fairing twice and wait another 12 hours). Fairing flush to the tape means that when the tape comes off your repair is slightly proud of the hull and ready for sanding.
Spooge applied (no need for it to be nicely flat, the sander will take care of flatnitude later). The 407 microballoons make the semi-clear epoxy look pinky-red.
Tape removed, leaving little thin squares to be knocked down flush to the hull.
With the blisters well under way, it is time to work on the transom paint. The paint is Interlux Brightside one-part Polyurethane in Matterhorn White (which has a slightly grey cast to it), it goes on over a two-part epoxy primer that is a paint to work with as the primer is thick with solids.
Third round of fairing in place on the transom and surrounding aft end of the hull. I’ve made lots of modifications to the stern over time, and the paint has protected the underlying fiberglass work from UV degradation.
Final primer in place, it took two coats to fill in the orange peeled surface, and then another day of sanding to work out the brush marks.
For some reason that makes no sense to me, I decided to attempt a roll and tip approach to the primer. This was a mistake, as the primer goes on super thick and doesn’t like to flow even when thinned as per Interlux’s instructions. The result was primer with fairly deep brush strokes in it, all of which had to be sanded out. The final prep surface is supposed to be 220-320 grit paper, which is getting pretty smooth (much smoother than the initial 100 grit prep for first coats primer, and 150 grit for second coat primer).
There are at least two ways to sand a surface; if you want to change the shape of the surface then you use a hard pad, and the pad will cut down high points and leave low points untouched. I have lots of those kinds of pads as most of the time one is sanding in order to alter the shape and make it fair. The other way to sand is when you don’t want to change the surface’s shape, but simply make the entire surface uniformly smooth. For that, I need a soft foam sanding pad that will follow the contours of the hull and cut into both high and low spots (particularly when dealing with compound curves typical of a boat hull). Svendsen’s had the perfect kind of pad for this (they would, as they specialize in sanding boat hulls), but they did not have any 220 grit gold sticky-back 3M paper in stock… and then they found a roll of 240 grit, which worked fine except that it takes even longer to sand sound brush marks in primer when each swipe of the sanding pad is taking off a really really thin amount of paint… so I sanded for five hours and got out the brush marks. Note to self: next time, do not tip off the rolled on primer.
Mixed with 15% of this…
And you get this. First coat on, two more to follow.
The application method for the paint was a 4 inch foam hot dog roller, thin to 15% (manufacturer says no more than 10%, I can’t get the paint to flow at 10%), roller on a thin coat in a vertical strip about two roller widths wide, use a 3″ foam brush to tip the paint horizontally and knock down the air bubbles from the roller, and move quickly. The polyurethane paint skins in less than a minute and you have to a) knock down the bubbles and b) get the adjacent strip of paint on. Goes pretty fast, and came out much better than the older paint.
And now I’m waiting for it to get warm enough to apply the second coat of polyurethane to the transom, and continue with bottom paint. Tomorrow Tim is going to suspend Beetle in the travel lift slings overnight and that’s when I can work on the areas of the hull where the cradle pads are, and also the bottom of the keel. So it’s going to be a fun day, no sanding, only painting!