Saturday 2 March 2019

Pouring Lead

At last the cold wet weather cleared, and the morning of the 19th February (my birthday!) dawned bright and dry. So I immediately set about getting the lead pour underway outside on the driveway.

I tackled the centre board first, for practice, with it requiring a relatively small amount of lead and being easy to set up.

Here is the centre board clamped to the saw horses and levelled flat.

I wanted to know exactly how much lead was going into the centre board and the keel, so I could be sure the boat is correctly ballasted.

I had previously cut all the rolled lead into pieces for melting, and weighed it all out using the old fashioned balance kitchen scales and brass weights. In the process of doing this I discovered that this method was only roughly accurate, so for the pour I used an accurate set of scales and switched to measuring in kilogrammes.

The drawings state that the centre board requires 9 kilogrammes of lead. I weighed this amount out in three lots of 3 kilogrammes, because as mentioned in a previous post I was doubtful that it would all fit into the aperture and I wanted to pour in smaller amounts until it was full.

Then I donned face shield, respirator, boots, overalls and heavy gloves. I think the neighbours were wondering what was going on.

Breaking Bad in Eynsham? Surely not?!

Then I fired up the burner and somewhat nervously started to melt the first batch of lead in one of my old stainless saucepans.

In no time at all it melted, so I skimmed off the dross with a stainless spoon and poured the first lot into the board.

It all went smoothly and I filled the aperture half full, immediately realising that as I thought there was no way it would take 9 kilogrammes.

The second pour filled it to just slightly overflowing, with a total of 6 kilogrammes used.

Here is the freshly poured and cooled lead.

So far, so good!

I then got set up to pour the front and rear keel ballast. I improved the shelter around the burner, partly to protect the flame from the light breeze but also to deter curious passers by from getting too close.

Then I set up the keel, like this.

Heavy building blocks hold the keel securely upright, and a pair of heavy duty F clamps hold them in place against the sides of the front keel so they won't bulge when I pour the molten lead into it.

This went smoothly and the front keel took 7 kilogrammes to slightly overfill it, so the drawings are correct here.

The rear keel pour then went ahead, with the clamps moved aft.

The compartment did not seem big enough to take the 42 kilogrammes specified in the drawings, but it easily swallowed it all up. Here it is full, with a gap left at the top to take the keel cap.

I poured in batches of 6 kilogrammes, since I thought that was the most weight I could safely handle in one go.

So that was the lead pour successfully completed. It took four and a half hours in total. I left the keel outside to cool until the evening before moving it back into the workshop. It is now too heavy to lift without help!

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