Sunday, July 15, 2007

Wingnet rails, part 4, and more finish primer

Saturday I worked on marking and trimming the wingnet rails. Ian doesn't give exact measurements for this, but by carefully measuring the dimensions on the deck layout plan sheet and using the scale factor to convert, it's not too hard to figure out what it should look like. I also spent some time looking the rails over while they sat in place on the floats, and doing some rough-in marks to make sure they would clear the access hatches:

Then I took them back in the garage, and drew in the final cut-out marks. I didn't seem to have anything suitably round in the garage for making the quarter-radiuses, so I improvised with a can of soup:

Yeah, I know clam chowder would have been more appropriate but we were out-of-stock -- I'll just have to deal with the shame.

After some jigsaw work, voila:

I also cut the rails down length-wise so that they ended 2.5" inside each beam location index dowel. I did this without much thinking though, and I now think I should have left them a bit longer just in case the beams turn out narrower than I expect. I'll save the cutoffs and in the worse case maybe I can laminate them back together.

I've put some thought into the sequence I should follow for attaching the rails to the floats. Bear in mind, I still need to scuff, re-prime, and re-sand my floats - and I think the wingnet rails could be easily damaged if they are attached to the floats while I'm turning them this way and that way, in order to sand the sides. So I'm going to do things in this order:

  1. Scuff the floats back up to 150 grit.
  2. Re-prime the floats.
  3. Sand the floats back down to 400 grit.
  4. Pre-fair the wingnet rails (leaving the taping surfaces as raw glass).
  5. Locate the wingnet rail attachment points, grind those areas back down to glass, and laminate the rails to the floats.
  6. Fair the rail attachment points and prime them. All of the attachment points are on or near the deck of the float, so I can leave the floats upright for this step.
  7. Paint the entire float, including the wingnet rail.

Once I'd decided on the above, this made scuffing and re-primering a big priority again. So I spent the last half of my Saturday work day, sanding down my floats to 150 grit again.

Today was a bit slow due to some family events. However, I did get my HVLP system setup again, and I put four coats of the finish primer on my starboard float. As I mentioned before, the first coat was gray to serve as a warning layer when I'm sanding (so I don't go too far next time):

My spray gun worked really well. The primer coats turned out much smoother than when I did them with the roller (when I start sanding, I think I'll be able to start right at 220 grit). My nozzle size is 1.1 mm, which is just below the range recommended by Alexseal (1.2-1.6mm). For whatever reason, it looked like the primer coats were going down very thin, which is why I continued on with three coats of white.

I need to get some more lighting in the tent -- otherwise it is very hard to see sometimes, where you've sprayed and where you haven't. For primer it's not such a big deal, but I imagine this could make things really hard for the top-coat application. I do happen to have a dual halogen worklight that I bought last winter -- I'll give that a try next time.

I also learned some lessons about hose management; it's easy to forget about the hoses, and I dragged them through the primer a couple times. Easy to fix, but I'm really glad I'm getting this practice opportunity now. I also used cable-ties to tie the sprayer and the respirator hoses together, which helped a lot when dragging them around.

I'm not sure I'm totally happy with the full-face respirator. On the plus side, it's easy breathing and it doesn't fog up. On the down side, it's hot as hell, fills up with sweat really fast, and it's hard having your vision constricted. I think tomorrow I'll order the half-face version, so I can compare.

On the 4th of July I had gotten some advice from my brother-in-law, that you should vary your pass directions. Eg, first pass uses a side-to-side motion with a vertical fan pattern, second pass uses a up-and-down motion with a horizontal fan pattern. I didn't really think this would be necessary, but boy was I wrong -- even when you're doing a good job of overlapping your passes, it's still quite easy to see pass "lines". So I flipped directions for my 2nd coat of white, and it did seem to help.

BTW, my HVLP system is looking much more manly now; not so nice and shiny anymore with white and gray dusty overspray on my hoses.

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