Thread: lead for ballast

Hi Andrew

Other people might have other ideas, but the best place I know of to find lots of it is around marinas. You'll need some diving equipment though. Hanging off the bottom of nearly every yacht is an appendage that contains vast amounts of scrap lead, much more than you really need. This can be hacked off with a saw, but getting it to the surface is problematic, so you might need a diving boat with a decent winch.

Andrew,

Woodeneye is almost correct. Marinas can be an excellent source of lead. Try ringing around and seeing if there are any derelict/abandoned boats preferably plywood. Old Diamonds have how much you need, so would Bluebirds, Hartleys the list goes on and you may score one for nix.

You may even score a lot more than just the lead... winches, saddles, blocks, toilets, sinks, lights the list is endless.

Another possible are tyre fitters, they often have a scrap lead bin for all the balance weights they rip off. Ditto wreckers.

Ditto tire shops. Around here, USED balance weights are considered hazardous waste, and cost $$$ to the shop for disposal. More than happy to give them away, maybe even with the bucket they're collected in. IIRC, the balance weights have antimony added for strength, which only slightly lowers the density. Such sources are also popular for DIY divers' weights and bullet re-loaders (where legal).

Another notion I've seen, for steel-hulled vessels, is concrete using steel punchings for aggregate. Steel fabricators are sources for the punchings. If they use water-based cutting fluids, easier to clean before mixing. Final density is on the order of 350-400 pcf.

Cheers,
Joe

I'm not sure of the gun laws there, but clean lead can be had as deer slugs, bird shot, etc. from gun supply stores. If you buy bulk, you'll save some, but expect to pay considerably more then dirty lead.

Scrap yards have dirty lead from several types of suppliers. Wheel weights are common enough, but also electrical wiring, x-ray equipment and other industries dispose of lead too.

Having poured several concrete ballasts over the years, all with "boiler punchings" and scrap metals in them, 350 - 400 pounds (159 - 182 kilo) a cubic foot isn't realistic. 200 - 250 (90 - 114 kilo) is realistic, which means you'll need nearly three times the volume (2.8 at 250 lbs, per cu. ft.) for this type of ballast casting, which often isn't a practical consideration, not to mention what will likely happen the the design's CG.

Right you are. I was winging it from memory. Even solid steel is only 490pcf.

As far as CG is concerned, the vessels in question were drydock caissons (tall and narrow), so not as much of a challenge for stability.

Cheers,
Joe

thanks guys,
actually walked into a tyre joint and they were happy enough to sell me their old weights for $1/ kilo. ( 20 for a bucket that was damn heavy. ) Havnt weighed it yet but I reckon it must be more than 20 kilos. So it seems pretty easy. all I gotta do is visit another 24 shops and i'm there. Then I gotta cast it. That will be the biggest learning curve I've had for a while. Thank God for the internet.

When I was a kid we used to get bucket loads of bullets from the rifle range , and melt them down.
Interesting , the military bullets especially.
But sounds like you are set already.
Rob J.

Actually, at a $1 per kilo, they got better then the going rate on junk lead. Secondly, if they are like here, they didn't have to pay you to take away hazardous materials! Most tire stores save up their wheel weights in hope someone will come buy and take them for free, other wise they usually have to pay a service to come out and pick them up for proper disposal.

In my little community, I routinly get 20 kilo buckets of weights, from several tire stores. I'm saving up for a 2,400 (1090 kilo) ballast casting I'll need to do soon. These folks are happy to be rid of the darn things, with most willingly paying to have them carted out of their shops.

I'm not sure if they have to pay to get someone to pay to take them away but I rang a couple of scap metal dealers and they wanted 1.80 / 1.90 so I figure I came out in front. Next tyre joint I may start at 50c. That was only my first bucket of about 25 so I have a way to go. Setting up for the melt is the scary part. I have a couple of questions, for now..
1... do I have to melt all the lead or can I make small ingots, pack them in the mould then melt extra to fill around them? Will the melted take to the ingots?
2... I think I'll make a ply mould, line it with cement sheet and seal the joins with plaster then pour. does this sound feasable.
3... I have to make a centreboard slot in the casting, but I have concerns about getting it out of the finished keel after, 'spose I could just drill and bash it out, or is there a better method?
4... Besides this and WoodenBoat forums does any one know of other forums to find info about lead casting?

Thats all for now

Andrew

Andrew contact Peter Sibley , he is an experienced caster (if thats the right word).
Regards Rob J.

Pity I cant get it from my work(nyrstar), perhaps you could go see the car battery recyclers and ask for a small amount.
Moulding lead is simple as it starts melting at 320°c but you will need a temp upwards of 410 to mould it, too cold it wont form a bond to itself as it will layer as it freezes.
Large volume casting can be problematic lead has a large shrinking rate that'll cause a large dimple in the center of the top and pulled in sides, what we do at work is to heat the top as the bottom is cooling this will allow for a even solidifying.
We mould lead in cast metal or 1"+ thick mild steel moulds, you could use clay as a mould, using wood and molten metal doesnt sound good but lining it with thick clay for a single use mould should be ok?

Originally Posted by AndrewPatrol

...
2... I think I'll make a ply mould, line it with cement sheet and seal the joins with plaster then pour. does this sound feasable.
3... I have to make a centreboard slot in the casting, but I have concerns about getting it out of the finished keel after, 'spose I could just drill and bash it out, or is there a better method?...

Andrew

I think so, for both.

If you add some silica sand to the plaster, it will be more resistant to cracking. Make sure it's dry before moulding the lead.

The dimensions of the slot might not permit a removable core, with adequate draft (sloping sides) for removal. But a waste core of wood would be easier to drill than drilling and bashing the lead. A clay liner shouldn't be necessary because it's waste anyway. I'd use the softest wood available (within reason), and make sure it's very dry; entrapped moisture could be very messy when molten lead meets it. Charring of the wood probably wouldn't be sufficient to create a bond-breaker.

What are the approximate dimensions of the ballast and centreboard slot?

Cheers,
Joe

Howdy,

With any method you have to be really sure there is no moisture in the mould, whether it is timber, sand or plaster of paris. Explosive bubbles.

Wooden moulds are not uncommon in boatbuilding, but you have to make them really strong so the lead doesn't push them out of shape (or worse push the bits apart so the lead gets out.

I would almost always go with getting a foundry to do the job. You can either make a pattern or a mould. Be aware that the lead shrinks as it cools so the mould or pattern has to be slightly bigger than needed. The foundry or someone here can probably give you a percentage figure. If you are lucky the designer might have taken it into account.

I've seen a couple of home pours end up on the grass (or what was once the grass - people also tend to gather around the point of interest so keep well away) or getting a bit exciting (read downright dangerous) because of moisture in the mould. For bigger jobs the amount of heat needed is really significant and has to be delivered quickly. Don't think you can use any aluminium containers or taps - they will soften or melt themselves for anything but the smallest amounts.

Looking at all that you have to do to get this to happen it is going to end up much cheaper and easier to get a foundry to do it. 24 tyre shops - what about 5 days on the road - petrol and time and uncertainty? Getting the right burners and a container strong enough with a tap, enough gas to do the whole thing, making the plug and then the mould (or just the mould), making everything strong enough to handle it, putting 500kg up high to melt so you get the gravity feed. I'd be saying it is easier, cheaper and safer just to make a pattern and get a foundry to cast it in their floor. It will end up cheaper in the long run and waaaay easier.

See if the foundry can work with a foam pattern - this can be much more time efficient for you to shape.

As a personal development project it has some merit of course.

Best wishes
Michael Storer

Did anyone mention car batteries for lead?

Man, melting and pouring lead carries a lot of risks, so I'd be leaving it to a foundry also. It also gives off nasty toxic fumes.

Did anyone catch the Mythbusters episode where the guys stuck their hands into molten lead? It has to be a very high temp, something like 900deg C. Too low, like 600deg and your fingers get cooked. Weird.