Thursday, November 29, 2012
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My new keel
Dawn rose...well 10:00am and rushed out to Bren's farm to check how the keel had fared overnight We loaded it onto a trailor - took it to a weighbridge which suggested that it weighted 360kg - about 95kg more than specified. But it was still in the mold and the weighbridge was only calibrated to weigh in increments of 20kg.
So we took it back to my house and unwrapped it from its mold. The mold had charred somewhat, especially the centre board slot, but nonetheless it retained its shape extremely well. The 150 plus dry wall screws did their job and no lead leaked from any part of the mold - so that was quite satisfying.
Brendan managed to source a professional scales from a friendly neighbour who runs a weighing and calibration business - thanks Kevin - and we weighed it out of the mold - 326kg in total. So by deduction it seems my bathroom scales were reasonably accurate. When we measured the keel against the FSP drawings, it seems we did add the extras lead unnecessarily so now I have the challenge of cutting off a slice off the top of the keel...shouldn't be too difficult!
Bottom line - the keel looks to be fine with a few pock marks on top where the molten lead continued to bubble, but this will probably be removed when I slice off the top of the keel.
The lesson learned were
1) refine the tap so that the lead is directed down into the mold - the pressure at the tap is quite high, presumably due to the weight of molten lead and tended to splash around, so we had to reduce to the flow to a slower rate.
2) Mark the level on the mold to where the lead needs to be poured - we poured extra since the mold didn't look full enough and I couldn't be sure if some lead had just escaped or leaked underneath. 3) The lead looked to be somewhat discoloured - as if heated higher than necessary - not sure if that made any significant difference, but may have reduced the bubbling and gurgling of the lead when it was in the mold and possible lead to increased charring of the mold.
The mold could have possible managed one more pour, but since the first was deemed a success I consigned the mold to the role of fire kindling.
Finally, I now have the task to cut the top inch or so off the keel, please feel free to comment on the best tools for the job.
My new keel
Dawn rose...well 10:00am and rushed out to Bren's farm to check how the keel had fared overnight We loaded it onto a trailor - took it to a weighbridge which suggested that it weighted 360kg - about 95kg more than specified. But it was still in the mold and the weighbridge was only calibrated to weigh in increments of 20kg.
So we took it back to my house and unwrapped it from its mold. The mold had charred somewhat, especially the centre board slot, but nonetheless it retained its shape extremely well. The 150 plus dry wall screws did their job and no lead leaked from any part of the mold - so that was quite satisfying.
Brendan managed to source a professional scales from a friendly neighbour who runs a weighing and calibration business - thanks Kevin - and we weighed it out of the mold - 326kg in total. So by deduction it seems my bathroom scales were reasonably accurate. When we measured the keel against the FSP drawings, it seems we did add the extras lead unnecessarily so now I have the challenge of cutting off a slice off the top of the keel...shouldn't be too difficult!
Bottom line - the keel looks to be fine with a few pock marks on top where the molten lead continued to bubble, but this will probably be removed when I slice off the top of the keel.
The lesson learned were
1) refine the tap so that the lead is directed down into the mold - the pressure at the tap is quite high, presumably due to the weight of molten lead and tended to splash around, so we had to reduce to the flow to a slower rate.
2) Mark the level on the mold to where the lead needs to be poured - we poured extra since the mold didn't look full enough and I couldn't be sure if some lead had just escaped or leaked underneath. 3) The lead looked to be somewhat discoloured - as if heated higher than necessary - not sure if that made any significant difference, but may have reduced the bubbling and gurgling of the lead when it was in the mold and possible lead to increased charring of the mold.
The mold could have possible managed one more pour, but since the first was deemed a success I consigned the mold to the role of fire kindling.
Finally, I now have the task to cut the top inch or so off the keel, please feel free to comment on the best tools for the job.
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