Balsa Bulb

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Balsa Bulb

Joined: 27 Aug 2014, 08:30

15 Dec 2014, 07:48 #1

Does anyone have a effective efficient way of shaping the Balsa bulb for the keel.
Ideally a lathe would give a perfect result. Not having one of these any other ideas for shaping ?
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Joined: 06 Sep 2012, 07:54

15 Dec 2014, 14:56 #2

Lead not Balsa!!
I was born intelligent, but my education made me stupid.
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Joined: 28 Oct 2012, 11:48

15 Dec 2014, 16:35 #3

First you make a balsa bulb then you take a mould of it then you pour the lead! I cut some slices shaped like the bulb, glued them together and then literally carved and sanded with a coarse sandpaper until I had pretty much the desired shape, I then finished off with finer and finer papers until it looked perfect. A word of caution, Once the mould was complete and thoroughly dried I poured the lead, sadly this bubbled in a most alarming manner and left behind evidence of the bubbles in the finished article. I need not have taken such care with the original balsa bulb as I had to expend considerable time and effort getting the final result smooth and good looking. Even now I shudder when I look at it and wish I had spent even more time on it. Good luck and happy sailing.
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Joined: 06 Sep 2012, 08:19

02 Feb 2015, 18:26 #4

One reason that the lead will bubble when being poured is if the pouring hole is too small. The air has no room to escape past the molten lead as it enters the mould.
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racingSparrow
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racingSparrow
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Joined: 06 Sep 2012, 03:27

12 Feb 2015, 08:46 #5

I agree with sarnian, a large pour hole helps, and also pre heat the mold in the oven just before you cast into it seems to help quite a bit. The mold needs to be really dry too.
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Joined: 04 Jul 2013, 10:53

07 Mar 2015, 23:48 #6

HI - I have done both methods ... used a lathe to make the balsa bulb and also sanded it by hand. Either method works fine so if you don't have a lathe then keep it simple and shape it by hand. The trick I found was to hold the varying degrees of sand paper in one hand and then spin the balsa in your other hand against the sand paper. That way you keep the concentric shape as you work it down to size.
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