Wednesday, 28 November 2012

Keel Pour

The forecast this morning was for clear skies and no rain - seemed like the ideal opportunity to pour our keel.  My friend Brendan is a farmer with lots of open yard spaces so we set up camp on his farm next to an old shed.  Bren's son Jordan did some final welding to secure the crucible and ensure the smelter was stable.

 Meanwhile Brendan was spreading pellets on his land:-

So time to finalise the smelter.  So far we had taken an oxy acetylene bottle and remodeled it into a crucible   This was encased by a steel drum with a smart side opening door for feeding fuel and a monstrous chimney, which was supposed to create a venturi effect and reduce the smoke in our vicinity.... and voila!

The smelter was a great success - the crucible became red hot burning only scrap wood from old freight pallets.  The chimney also worked a treat - although the wooden post we used to prop it up burned through - even though it was about 3 ft away from the top of the burner.  Also the aluminium pop rivets we used to hold the hinges on the door, melted away, so we had to replace with self tapping screws - suggests we were getting a decent fire going!

I weighed out 270kg of lead ingots which I had already smelted (see earlier post) and once the crucible was hot enough (reading >500 deg celcius on temperature gun) stacked them into the crucible.  Less than 20 minutes later I heard a rumble from within the crucible and upon inspection, it appeared that they had melted.

Time for final preparations to the mold, ensuring it was level and scorch the inside with a gas torch.   When it was time to pour, I was too busy to take some photos but I had a video camera running in the background.    The tap we made was fairly leak-proof, only a tiny dribble of lead leaked.  However it did not pour very accurately so we had to makeshift some barriers to direct the lead flow into the mold.  Surprisingly the 270kg of lead (weighed on a bathroom scales) did not completely fill the mold so we melted a further approx 50kg of lead and topped up the mold.  I am not sure if the final amount was necessary, as closer inspection of the lead keel mold plans suggests it does not need to be filled to the brim.  I was pleased that the mold held up, without being encased in sand and there were no leaks.  However, lots of bubbling ensued, maybe the wood in the mold was not bone dry, even though I had it stored in my garage since I made it last month.

Tomorrow, we intend taking the keel to be weighed on a calibrated scales to see if we have poured too much lead or was I using an incorrectly calibrated bathroom scales.

It was dark when we were completing the final pour - so you like I will have to wait until tomorrow before seeing the finished result!

Meanwhile, here are some updates on the planking - managed to get another pair hung:-

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