Omeron
02-05-2009, 08:55 AM
Manufacturing a Lead fin and bulb keel for a sailboat of 35 Ft seems to be one of the most dounting jobs for an amateur builder, as well as one of the most expensive items if built professionally.
I have long been thinking about a method, which did not need a furnace, and handling of large quantites of heavy molten stuff. And would ask your opinions on its feasibility.
I guess any keel requires a pattern to begin with.So i would start with that but a half model cut in half along the span of the foil and the bulb.So you need to cast it twice to get the two halves. This ofcourse requires the bulb to be symetrical fore and aft, so that they dont face opposite directions when brought together.
The pattern is then laid flat in a hole made in the ground and lined by a suitable material such as sand,concrete mixture or else.
Once you have your mold ready, you have half of your keel with an open surface. This void in the ground is then filled by lead shots, wheel weights or any lead particles which you may have and melted by a propane torch used by roof makers.
You only need to place a bit of lead in the mold and melt it. As it doesnt need to be forced into any cavity, the gravity will do the work. So add bits and melt, add bits and melt. It can take as many times as you wish to fill it to the surface. You can also place big chunks in the middle, and fill the gaps around it. All you need is a bit of molten surface to stick to the other piece.
No bubbles, no void spaces.
When nearing the surface, place any steel structures, bolts,what have you and continue encapsulating.
The two halves can then be ground, faired and bolted together to make the finished keel. Infact you can place round objects wherever you want to create the bolt holes.
This to me looks like a childs play, and does not require any special tools or skills or create a hazardous, irreversible situation like making a mistake during melting and pouring molten lead.
What do you think?
I have long been thinking about a method, which did not need a furnace, and handling of large quantites of heavy molten stuff. And would ask your opinions on its feasibility.
I guess any keel requires a pattern to begin with.So i would start with that but a half model cut in half along the span of the foil and the bulb.So you need to cast it twice to get the two halves. This ofcourse requires the bulb to be symetrical fore and aft, so that they dont face opposite directions when brought together.
The pattern is then laid flat in a hole made in the ground and lined by a suitable material such as sand,concrete mixture or else.
Once you have your mold ready, you have half of your keel with an open surface. This void in the ground is then filled by lead shots, wheel weights or any lead particles which you may have and melted by a propane torch used by roof makers.
You only need to place a bit of lead in the mold and melt it. As it doesnt need to be forced into any cavity, the gravity will do the work. So add bits and melt, add bits and melt. It can take as many times as you wish to fill it to the surface. You can also place big chunks in the middle, and fill the gaps around it. All you need is a bit of molten surface to stick to the other piece.
No bubbles, no void spaces.
When nearing the surface, place any steel structures, bolts,what have you and continue encapsulating.
The two halves can then be ground, faired and bolted together to make the finished keel. Infact you can place round objects wherever you want to create the bolt holes.
This to me looks like a childs play, and does not require any special tools or skills or create a hazardous, irreversible situation like making a mistake during melting and pouring molten lead.
What do you think?