Filling hull joins

Filling of Hull Joins Continues

Posted by Paul

I didn’t get much done today, I started late and finished early! I did get the rest of the outboard joins of the port hull filled, including removing the fairing tabs and filling the voids left behind them.

Well almost, I still have a few tabs to remove and also the join to the keel panels to fill but I also have a big gap down the middle of the keel panels to fill also which I am leaving until last. So I am not even at half way really! Normally a hull would have 6 joins to fill, I have 7 when you include the one down the middle of the keel. I have now filled 2 of them so I am about a third of the way through.

But I did learn something today. I used way too much filler yesterday. I overfilled in the belief that I needed to build the filler over the edges of the joins so that I could sand it back to a nice round join. That is still true, however, I overdid it, and I can still achieve the same result using far less filler and effort.

I found that even when over filled you could still get valleys (low spots) that need extra filling so if you have to fill again anyway, you may as well do it without the extra sanding that is required when you overfill. For example, I had as much as 2mm of overfill in some places but you sand it all away to less than 1/4mm to 1/2mm and in places I still had areas that were lower than the rest of the join requiring another fill. A lot of hard work and a lot of wasted filler and I would have had the same result using a lot less work and material if I just fill to flush in future and fill the low spots later. The only places where it is ok to have more filler is where you have uneven panels that need the filler to level them out.

Ironically, the dust that is created when you sand the stuff off again is almost identical to the powder used to make it! I sanded a section first up today so that I could find out how easy it was to sand back and to see if overfilling was the way to go. Sanding is not a pleasant task. All of the stories you have heard about sanding and fairing are true! I know this from sanding just a 1mt filled join. It is hard work and anything you can do to minimise this is a good thing! It’s funny, you hear other builders go on about less is better to minimise weight. Listen to them. If weight doesn’t motivate you, use cost, or use workload. Less weight, less waste, less work, it all means the same thing. I spent a half hour or so rigging up the vacuum cleaner to the orbital sander which removed about half the dust. The rest made sure it hung in the air a while (I was wearing a mask!) so that it could permeate through my clothing. I was using an orbital most of the time so I just had to apply the downward pressure and believe me it is still hard work. I also used a sanding board I have made at about 40mm. Also hard work. I cant wait to start fairing! Yeah right!

The sequence of pictures below show that using less filler makes no difference to the end result except you use less filling materials and you do less work to get it back to where it would have been anyway.

too much fillertoo much filler still get valleysclose up of valleys in filler

close up of less fillerless filler is betterinside of hull showing value of tape

So the plan from here is to use as little filler as I can. If I get any areas that are too low I will fill them again after I have sanded back the little that I do overfill.

Tomorrow I will start on the inboard side of the hull (after I remove the few remaining fairing tabs and fill behind them). Then I will start to work on the keel.

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