Lead Casting?

[SanFran 6]

There's a spare keel somewhere near Billy Goat Point if your keen

[Kick Ass 25]

On 23/01/2021 at 3:43 PM, Steve Pope said:

you can always do it yourself, lots of folk did their own back in the day.

Would be keen on this if I could get my hands on some gear to handle 1300-1400 kg of lead

[Kick Ass 25]

On 23/01/2021 at 6:02 PM, TCat said:

My understanding is the price has increased quite significantly - there are health and safely issues working with lead so that may be part of it - as well as general supply and demand. The tauranga option was cheaper from memory but then you have to factor in transport. 

A trip to Tauranga to pickup wouldn't be an issue if the price was right.

[Frank 28]

On 24/01/2021 at 7:35 PM, Kick Ass said:

A trip to Tauranga to pickup wouldn't be an issue if the price was right.

1.3 Tonnes is not that heavy you should be able to move that with a half decent trailer and your mates ute.

A few years back I had a 1000 kg keel cast to replace an old concrete and steel punchings one which was useless but weighed the same when out of the water.  I took the old one to the tip with my dodgy garden trailer and a 1300 cc car with no problem. 

 later I considered casting a Carpenter 29 keel myself but after hearing all the horror stories of DIY casting gone wrong I paid Terry Bailey to cast it. Yes it was expensive (even then) but it was worth it. 

For DIY I was told to use  an old steel or cast iron bath tub to hold the lead and just firewood underneath for heat.  The plug trim was to  be removed and replaced with an all metal valve of some sort. Any plastic or solder in the assembly would melt with possibly disastrous results .There should be a steel pipe leading to the mould. 

The C29 mould was made of reinforced plaster (like plaster of paris) and I was told to bury it in a slit trench with lots of sand packed around it and two coats of house paint on the outside as a moisture barrier. Any moisture in the mould results in some sort of steam eruption, .... not good !. If you are using a steel mould it must be preheated or it will buckle but it does not need to be buried.  To make a plaster mould you first need to make a wooden plug. 

I'm sure these days there are lots of you Tube videos on this but my mate tried to cast a 3000 kg keel in an old bath tub where unbeknown to him the plug trim was soldered in. When the lead melted the trim came free and floated to the top, resulting in all the lead roaring off into the farmers paddock mixing with grass and cow sh*t. Two weeks of chopping it up with an axe and a chain saw and they had another go and all was well.  The owner of the outfit that cast my 1000 kg keel said guys used to turn up with a trailer load of chopped lead mixed with  grass, cowshit, gravel and/or dirt , saying "please can you cast my keel"   

[Tamure 408]

Ive cast small lead items, up to 50kg and its pretty straightforward. Big items like keels need some thought but remember people used to do it all the time  very successfully in the heyday of boat building. You need to plan it carefully, a ton or so of boiling metal has serious health and safety implications!

[Frank 28]

You also need to have a decent butane torch and some unmelted lead to use as the lead cools. This is due to shrinkage causing a cavity at the top, you keep that bit ,melted with the torch and fill it with the remaining lead until you have a level top surface. 

[Tamure 408]

you can get the keel/bulb cnc shaped in foam then build the plaster/wood structure around it, you need lots of heat and big torches to keep the lead flowing. Plenty of info on the net about it, think you'll need  a bit of antimony as well.