2015-12-13

Post XLIII - Paint mini-post

Could not wait to add this post. I finished my first coat of paint on the hull exterior tonight! I decided a long while back I was going to go with Pettit Easypoxy brand -- this paint is oil-based (and therefore doesn't completely suck), brushes or rolls on, cures glossy and flat, and is generally the easiest thing to apply with a rookie setup like mine. I've used it for a tonne of other boat paint jobs and in my opinion there's nothing better.

SURFACE PREP -- I put that in caps because it's super important for marine paint. First: the entire hull needs to be sanded or at least roughened with sandpaper. Not sure exactly what is recommended, but I went with 100 grit here. Worked fine for me. Second - all dust needs to be removed and then the whole thing should be wiped clean of residue using acetone or 99% isopropyl alcohol (I use the former). If you take these steps you can go directly onto the epoxy with no primer. If you fail to take these steps, the finish is virtually guaranteed to peel.

Figure 217: Taped gunwales and sanded, acetone-wiped hull surface



The only (and biggest) problem with Easypoxy is that their stock colours are 90% horrible. The only one that appealed to me at all (apart from black & white) was the colour I bought for my canoe years ago -- electric blue! The name belies the darkness of blue when cured; it's actually pretty attractive as a hull colour if you favour darker hulls as I do.

A friend told me awhile back that Easypoxy is best applied dry-to-whet. Brush from un-painted areas into painted ones. The bristles lift gradually out of wet paint if you brush this way, and it allows the paint to lie flat again and retain the glossiness. Going the opposite way takes chunks out of the wet areas that don't fill in as readily. I use this technique every time I paint with Easypoxy (or other gloss paint) and it works great.

I typically apply by loading the brush, then wiping only one side on the edge of my container. I paint using the wiped side and the glossy paint oozes onto the boat surface through the bristles at a more-or-less steady rate.

Figure 218: The firs blobs of paint on the port bow!


The other thing I like about Easypoxy is that it beads nicely and, except for inside corners like the hull-gunwale joint, you can draw up to a line with very little effort. I met the graphite-epoxy waterline without the need for tape.

Overall, the experience was about equal to my other experiences with the brand. A nice, glossy coat that flattens almost immediately and then tacks up within an hour. I'll apply the second coat tomorrow night. It's best to do this after it dries but before the paint reaches full-cure (7 days) if you want the coats to bond chemically to one another.

Figure 219: Starboard side all painted up.


Figure 220: Portside bow all painted up


Figure 221: Aft starboard side, and transom painted up to the transom cap piece.


2015-12-11

Post XLII -- Another BIG SAND, and the Start of the Finish

I'm happy to say I'm getting down to the last few items before this boat is ready for paint. The last few sessions have been short and sporadic, but I've been taking advantage of the off-schedule to get done little jobs. First among these jobs was sanding the scuppers. Knowing that I'd be covering them in epoxy + varnish, I rough-sanded them with 100 grit. It was a bit painstaking doing 12 scuppers on each side, but they look much better for it, and are not so apt to catch fingers or cut hands.

Figure 206: Un-sanded scuppers


Figure 207: Scuppers post-sanding


The last and most nagging finish item was the bow. At this point, I realize there's very little I can do to make it look beautiful. The best I can hope for is a competent-looking repair job. I scarphed the gunwales back to the forward-most screws and made some short pieces to carry out to the cutwater. These short pieces were glued-and-screwed in place, and actually look half decent now that I've blended them to the rest of the gunwale by sanding. I don't have a pic right now but will try to remember to update the blog down the road. 

Figure 208: Gunwales cut back to receive new extensions


Figure 209: Extensions in place. This has been sanded since and looks decent.


In a longer weekend session I started the final BIG SAND of the boat. I had to smooth up the interior in preparation for paint & varnish. I'm going to paint below the decks for better waterproofness and varnish above. This went a bit quicker than the outside, but was still utterly painstaking. I'm glad it's done. I switched to 80 grit on the inside -- 60 grit was a bit too aggressive and I didn't want to go through the FG cloth by accident. Yet another instance where I'm glad I bought the RO sander that hooks to the shopvac. This would be a hellish job if I didn't have a dust removal machine operating the whole time. 

Figure 210: Sanding in progress. 


And finally came the interesting part -- the bottom coat. It's always more fun adding stuff to the boat than removing stuff (especially removing stuff with sandpaper, ugh)

The bottom coat is epoxy mixed with the WEST 423 graphite additive. The graphite is a solid lubricant that is supposed to protect the hull when it takes a hit. When I strike a pointy rock, the idea is that the graphite coating will help the boat slide off the rock, turning what could be a penetrating blow into a glancing blow. Not sure how this will all play out in practice, but I read lots of endorsements for the use of graphite additive as a bottom coat and decided to try it out. It was going to be painted anyway, so there's no harm in it.

Before starting to apply the bottom coat, I taped off the water line. The graphite (based on a test patch) does not thicken the epoxy very much and it *will* drip before curing. Taping off saves a lot of work cleaning up drips.

Figure 211: Waterline all taped up


The graphite-epoxy mixture (3/4 tbsp in 5 pumps of epoxy/hardener) paints on easy -- just like straight epoxy. I works best to brush from dry into wet areas, with a medium load of epoxy on the bristles.  

Figure 212: Closeup of the finish with tape still on



Just before final cure -- maybe 60min after application, depending on room temperature, is when the tape should come off. Remove it just after the epoxy tacks up (and stops running), but before it hardens appreciably. I stuck the tape down real good before starting, but I still had some seepage of epoxy underneath. The resulting line has some "hairs" for sure, but will be hidden by the paint before long.

The result wasn't perfectly symmetric. Not sure if this was my crappy attempt at marking a waterline, or some asymmetry in the hull. I don't much care at this point -- you almost never evaluate both sides of a waterline this way, except when it's under a builder's self-deprecating scrutiny in the workshop!

Figure 213: Closeup of the finish with tape removed -- note the "hairy" line left behind


Figure 214: And an overhead view showing the slight asymmetry. Oh well.


The very last thing to do before paint was to fix up my mistakes from sanding. Places where I got a bit overzealous, I ended up penetrating the cloth layer. You can see it in Figure 215, just above the gunwale. Nothing too bad, but I didn't want to leave anything to chance. I took unthickened epoxy and painted over any that the weave was showing. These areas will receive a final scuff sanding before I apply the paint. Yay...more sanding!

Figure 215: Slight penetration of the FG cloth near the gunwale. This will be sealed up



Figure 216: The hull, showing areas I painted over. These will be sanded later


Finally, I took the opportunity to put a nice round on the underside of the outer gunwales before I paint. I figure it's a good idea to get this out of the way so I don't have to worry about accidentally scuffing the new paintjob later on.  That's all for now. Next up is the paint job -- stay tuned to learn the EXCITING COLOUR that I picked!!!