Fairing, Starboard Hull

Ho Hum…. Still Sanding

Posted by Paul

I only managed an hour today. I am definitely past half way now with all of the outboard side sanded except as mentioned yesterday for a lot of un-sanded low spots that I have to decide to either fill or keep sanding down to flat. If I decided to keep sanding then I have about an hours work to finish, if I decide to fill the lows I probably still have an hours work but a lot less of it would actually be sanding. Here are a couple of photos to show what I mean.

low spots 2low spots 1

In the first pic I am know that I could easily sand it out but if I am going to go to the trouble of filling the size valleys like in the second photo then I may as well fill them all and save a lot of sanding. As you sand through the bog and start to hit the resin of the glass then the sanding gets slower because the resin is harder to sand and also because more care needs to be taken not to damage the glass by sanding through it too far. On the first hull I kept sanding until all of the low spots were gone. This means that the hull has as little bog in it as needed to get it fair.

On this hull I am thinking that the amount of bog left on the hull that could have been sanded off is negligible in terms of weight and also in terms of actual fairness. The low points on the deepest valleys are less than half a mm below the height of the highs around them so that means I would be sanding half a mm more bog away in that area to make it smooth, and if a section is half a mm lower in a gradual sanded incline than say the area a meter away all around it, the eye simply cant detect such a small change in height and it just looks and feels smooth and flat. And remember this is the worst of them many are even less than half a mm.

My fear in this method, is that having not been sanded (because the flat sander can’t yet reach it), the bottom of the low points may not be able to bond to the bog (because they are un-keyed for a mechanical bond) and because they are so shallow that the bog will just pull straight out the moment I try to sand it again. I am going to talk to the panel beater a few doors away to see what he thinks, as he would often work in similar situation with the same materials albeit on cars. Either way I have about an hours work to do on the outboard side until I am happy with the finish. I have sanded about a third of the inboard side. I will not be as fussy with this side of the hull as it is under the bridgedeck. So perhaps I can have the sanding of the bog done by Saturday afternoon and then maybe get 2 coats of resin and the first coat of highbuild on by Sunday night. I am stoked at the progress on this hull so far.

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