View Full Version : Lead pouring 101....
05-26-2002, 10:50 AM
I'm finally putting together the mold for my ballast keel. It's a female mold "design" that I copied from a photo journal somebody put up on the web somewhere. It's made of two pieces, port and starboard, built up out of "slabs" of scrap "2 by" lumber stacked up. (Hope that makes sense, no pictures yet. Think of a "reverse" or "negative" image of a half hull model...) I've got a couple questions for those of you who've already been through this ordeal. First off, what, if anything, can I use as a "fairing" compound on the shaped surfaces? It's already pretty smooth, but of course there's a few "low" spots here and there, and the seams between the 2 by slabs will want something in 'em to seal things up if I don't want to just wind up with a big puddle of molten lead at the end of the day... Is there any "foundry" putty or something similar designed for this purpose? I've thought about maybe plaster of some kind, but I worry about any residual water content reacting explosively when I pour the hot lead in there. I suppose I could just dig a big hole and "encase" the whole thing in packed casting sand and then fair up the keel afterwards, but that seems pretty tiresome if there's a better solution. Second: I remember reading somewhere about someone coating his wooden mold with a special "glazing" compound to prevent charring. Anybody familiar with this stuff? Would it possibly serve as a "fairing" compound as well? Or is it more like regular paint in consistancy? Pretty easy to find a local source for it or is it something I'm going to have to order from a specialty, foundry supply outlet? Anybody in the Seattle area know which of the local foundries are familar with keel casting? I figure there's got to be at least one near by with all the marine trades here and I hope to go visit and pick their brains a bit. Perhaps I can also pick up some supplies like the glazing from them too? Lastly, just how "bulletproof" a container am I going to need for my lead melting "crucible"? I'm not sure yet exactly how much lead we're talking about here, but the finished ballast keel will be roughly triangular in shape. About 5 1/2 feet long at the top edge tapering from an inch and a half at the stern to about 5 or 6 inches or so at the widest part before meeting at a "sharpish" point forward. With the "rake" fore and aft, the lower edge is only going to be about 4 feet long with about the same tapering, slightly reduced. It'll stand about two feet high at the taller, (deeper?) forward end. About four inches high at the stern. I'm "guessing" maybe 8 or 9 hundred pounds? Anyway, I'm hoping to stumble across an old cast iron bathtub somewhere, but if not, would something like an old oil barrel or similar serve with that quantity of lead? Any other ideas? Thanks, guys... I'm not looking forward to this little job. Scares the hell out of me!
[ 05-27-2002, 12:55 PM: Message edited by: Art Read ]
05-26-2002, 12:00 PM
8 or 9 hundred pounds ain't much volumetrically...with pigs or wheel weights it could be dome in four or five 2 lb. coffee cans with three or four pourings each.........
05-26-2002, 12:13 PM
Well... Like I said, I'm just guessing on the weight. Never dealt with lead in bigger hunks than I could carry around before. Surprisingly, the plans don't specify it. Just total displacement. 1,923 lbs. I seem to recall another similar design calling for about 900 lbs. And I can easily believe I've already put about thousand pounds of wood into the hull but I really don't know. Seems like the volume I'm looking at is gonna take more than a dozen or two coffee cans full. More like a few five gallon buckets... Maybe that's the next step. Fill it up with sand and see how much it takes "volumewise"?
05-26-2002, 12:21 PM
I bought used wheel weights from the local tire store, a 5 gallon bucket yeilds about #100 (after skimming the clips and crud off).
The following is based only me experiences;
I had some links saved, but they were on they old board. Cleaning up the rough edges really isn't that hard, as the lead is worked very easily. The gaps you are referring to; as long as they are huge, the lead will solidify pretty quickly and should leak through (too much). Multiple pours, you will need to keep the prior pour liquid (at least on the top) as to allow the new lead to bond to the old (propane torch).
05-26-2002, 12:50 PM
The "seams" between the individual slabs would probably be okay, but I suspect that the joints between the two halves and along the bottom piece I'm going to fit to close it off and help hold everything together for the pour will need something to "stuff" 'em up. Not the best joinery work I've ever done... And the lumber itself is pretty "rough". Couldn't see bothering to re-mill it all when it'll be firewood as soon as the keel hardens. (Hopefully not AS it's being poured!) Must be something I can shove in there that won't explode, burn or melt? Maybe just some cotton caulking covered over well with that foundry glaze?
05-26-2002, 12:57 PM
Maybe another layer of ply or masonite spanning the gap (on the outside) to limit the oozing. If I am picturing this right. Then shape the little flang off (an old hand plane works well).
BTW, check your e-mail.
[ 05-26-2002, 01:57 PM: Message edited by: capt jake ]
05-26-2002, 01:12 PM
As I recall, the material you're talking about is isinglass - a liquid you paint on, several coats, and which provides some protection.
I'm a little concerned you're planning a relatively large pour into a wooden mold. I know it's common enough in smaller keels; I just hope that it will work with 900# of lead. Much of it will probably turn to charcoal (which will still hold the lead) - but will have no strength. You'll have to convince yourself that enough uncharred wood will be left so that the mold will have sufficient strength.
It might not be a bad idea to bury it flush with the ground and tamp it 'round, to make sure that it won't collapse even if it does char. You could always stand by with a hose to douse it, but you do NOT want water to contact molten lead by any means.
You can seal the joint between the two halves with refractory cement, or failing that, plaster of paris. Lead will weep through surprisingly small gaps, so you should be careful to seal that joint well; since it's wood, lead weeping through a gap will tend to enlarge it. Another argument for burying it.
You might want to consider burying a 1/2" eye bolt in it to handle it by. You can put a nut on the end, slather it with stove polish, then it will unscrew when you are done.
Another thing you haven't mentioned is keel bolts. I'd suggest you cast the holes when you cast the keel, by incorporating cores (wood will work). Lead is horrible stuff to drill, and I've had poor luck with it (though others here may have advice which would help).
900# of lead is less than 1.5 cubic feet. You could make an excellent foundry vessel out of a discarded 20# propane tank, carefully purged, with one end cut off. I'd be leary of things like coffee cans; they're liable to collapse when you grasp and tip them to pour, and you'd be lucky to do more than 10-15# a try; that's 60-90 pours, and your keel would be a lot of poorly amalgamated layers. A single pour is what you want. I wouldn't consider melting this much lead in anything but a steel vessel with 1/8 - 3/16 walls minimum, and one you know couldn't collapse in an interesting way with all that lead in it. And make sure it can't tip, or that whatever is holding it won't tip or collapse either.
Also, the lead will contract as it cools, and probably open up a central cavity or hollow spot; you'll want to heat and fill this with molten lead.
You'll want a heavy metals respirator, heavy boots and clothes, and give careful consideration to how you'd avoid 900# of molten lead if anything breaks or collapses. Personal contact with THAT could seriously ruin your day.
My own keel pouring was much larger than yours (7800#) so I didn't even consider a wood mold (I used weak sand concrete), and I used a 2 bathtubs (which was chancy). Otherwise, I did many of the things I mention above.
05-26-2002, 01:52 PM
Isinglass and refractory cement, eh? Great! Thanks!
I hear what you're saying about taking precautions. I'm just pleased to have gotten this far with all my various digits still attached and don't want to wind up in a burn unit at this late date. As for the wood mold, my original idea was a male "plug" with sand or cement casting, but having seen that website I mentioned, it seemed a simpler solution. The "slabs" for the mold are made up of 2 x 6s, laid flat, side by side, less the hollowed out area in the center that will hold the lead. Mechanically fastened together. So I'll basically have a six foot by one foot by three foot "cube" of solid wood with a hollowed out area in the middle for the keel. Seems like there will be a lot of "meat" left even with considerable charring. But I'll bury it anyway just in case and to make the "pour" easier. I'm not familiar with refractory cement, but I'm wondering if skim coating the inside of the whole mold with it, as well as filling all the gaps, before appling the isinglass "glaze" over all wouldn't help? As for the pour itself, I looked at one guy's website where his elaborate "plumbing" failed right at the start of his pour and he wound up just "bailing" the lead from the crucible into the mold. Seemed to work pretty well for him, but I imagine you'd have to work pretty quickly to avoid the lead in the mold cooling too soon. Perhaps a couple of people with gauntlets, face masks and leather aprons and big "bailers"? Might be easier and more "foolproof" than engineering something more elaborate... Or maybe just multiple, smaller crucibles that can rotated over the burner and "manhandled" to the mold... Hmmmm... Got a lot of thinking to do still.
[ 05-27-2002, 01:06 PM: Message edited by: Art Read ]
05-26-2002, 04:43 PM
I think that the above "eisenglass" may actually be "waterglass". It also goes by the name sodium silicate. It's the stuff they use to make breakaway bottles for movies. Grandma used it for preserving eggs. We've used it, mixrd with a filler, for a high temperture glue. By itself, it dries to a brittle clear solid that looks like glass, seals air tight and withstands high temperatures. Whatever you use, test it with molten lead, before you committ. Where are you getting your lead ?
05-26-2002, 10:28 PM
I poured lead into a wood mold. The paint I used was Pyro-Paint 634-BN from Aremco Products (Ph. (845) 268-0039). Two coats prevented the wood from charring. The paint is expensive but worth it if you are going the wood mold route.
I would caution you that there may still be off-gasing from the wood as temperature of the molten lead bakes the wood fibers. If you have any knots or heartwood in the 2 X lumber expect the sap to bubble and spatter through the molten lead.
I had difficulty in getting the lead from the drum I melted it in, to the mold. The pipe at the bottom of the drum was too long and became blocked. I got the lead out but I ended up with a stratified mess and cut the keel up and redid the pour using a cement mold.
If your stack of wood is free of knots and is oversize so that you will have extra lead to shape on the sides, go for it. I wouldn't bother to fair the inside of the mold. It must be leakproof as the molten lead is as fluid as water and will find the holes and make a hot exit. Once hard and cool, the lead is easy to shape with a powerplaner or a sureform.
Good Luck, Be Safe
05-27-2002, 07:54 AM
So much for my memory. Paul's right - it's waterglass.
05-27-2002, 11:11 AM
I wondered about that... Isn't isinglass what they used to make old horse and buggy "windows" out of? But thanks for all the feedback, guys! I'll keep you up to date and solicit further advise as my "plan" comes together... Not going to start melting any lead before running my intentions past the "comittee"!
And, Paul... That's a good question. I've waited far too long to start searching. So far, all I've got is a half dozen wheel weights SWMBO has brought me for "inspiration" that she's found in the road while out jogging... I also know a guy who works for a big tire "chain" out here. Going to see what he knows about the chances of collecting enough locally to get the job done. Worse comes to worse, I know of a couple scrap dealers who'll have all I need. ($$$) Any of you "locals" have any other good ideas?
05-27-2002, 11:30 AM
" If you have any knots or heartwood in the 2 X lumber expect the sap to bubble and spatter through the molten lead. "
Hmmm... Well, there ARE going to be a few exposed knots I'm afraid. It was just scrap from a neighbor's building project after all. Nothing loose at all, or obviously "sappy" but... When you say "bubble and and spatter through the lead do you mean it will leave obvious voids and fissures, or just that I may have to be on guard against getting splashed by the hot lead itself? Both? I'm kind of expecting a few "defects" in the casting. I understand they can be "repaired" after the fact, if not TOO serious, by heating up the area with a torch and melting in a bit more lead? As for splashes of hot lead, well, I plan to use a LONG handled something or other and full welding gear while the lead is hot. I understand there are places that actually rent that kind of gear? Protective clothing and face masks/filters, etc?
" I ended up with a stratified mess and cut the keel up and redid the pour using a cement mold. "
Was this just because of too much delay in pouring the lead? How much time are we talking about here. I can see that a continuous pour is the "ideal", but assuming I wind up using multiple, small "crucibles" to melt it, can I expect to get a good casting even if we pour it in there one "batch" at a time, one right after the other? I can probably enlist a helper or two. This stuff is right up "Toot", the "cannon maker's", alley, but I doubt I could use that mold twice, if the first attempt fails...
[ 05-27-2002, 12:52 PM: Message edited by: Art Read ]
05-27-2002, 11:52 AM
To ensure you have a continuous pour, make sure you have some kind of heavy-duty torch to heat the pipe with. Once the lead starts flowing, it should continue just fine.
Most of Ceol Mor's keel is wheel weights. I used to drive around to service stations, and offer to buy their used wheel weights for a reasonable price; back then, it was $.20 per pound. You can see what a scrap dealer would give you to get an idea of a fair price. I'd have an old bathroom scale to weight the weigts, and some 5 gal buckets to dump them in. I collected as much as 700# at a go. I'd usually get one of three answers: (1) sure (jackpot) (2) extreme suspicion, nothing doing (3) I already have a deal with a dealer (nothing doing) or I'll sell the wheel weights if you'll buy the old batteries (no deal). Twice, I got answer (4) - consternation 'I threw 600# into the dumpster last week).
05-27-2002, 12:26 PM
Ross, I'm still not sure just how I'm going to actually melt the lead. I guess it really depends on how much "volume" I'm really looking at. Gonna figure that out today. I don't have easy access to any welding equipment, so the the idea of multiple, small containers is appealing if it wouldn't be too cumbersome or slow, or neccesarily result in a "stratified" keel. I do have access to lots of propane burners and even a couple of those "flamethrower" type propane weed burners. A lot of fast, concentrated heat... If need be, I'm sure I can find someplace to jury rig me a "plumbing" system to direct the lead, but from my reading of other people's pours, that always seems to be where most folks run into trouble with this. At any rate, since I still don't even have the lead, it'll be a while before I have to decide. Encouraging to hear you could collect that much at one go, though!
05-27-2002, 01:33 PM
Have you looked into what a commercial foundry pouring into your mold might cost you? I know there are some small art foundries in the area that might be able to do a pour like that. My helper at the shop is a blacksmith and works with a lot of other small craftsmen working in metals. I'll ask some questions and see what I can scare up. The added cost might be well worth the certainty, safety, and time.
05-27-2002, 02:46 PM
Maybe talk to your local automotive battery recyclers. One in Vancouver poured a 400 lb keel into a wooden mould, no problems. Price was only slightly higher than I'd been quoted for buying the lead as scrap elsewhere. Waterglass works fine. I'd be more concerned about mould deformation than combustion.
05-27-2002, 06:06 PM
Sounds like you've got in round numbers, 5 ft long by 2 ft high by 3 inches wide. If those were good averages, then you'd be dealing with 2 1/2 cu ft. At 720 lb/ft^3 thats 1800 lbs. Note that at the bottom, the pressure will be 2ft x 720 ft^3 = 1440 #/sq ft, or 10 psi. Burying this rig in the ground sounds like a great idea if you can't get someone to cast it for you. Do you really want to have a ton of melted lead slopping around? Gives me the creeps just thinking about it.
05-27-2002, 10:49 PM
My problem with the bad pour was that it was not continuous :( . The spatters and bubbling were just that. I was wearing a respirator for (cartridge for welding vapors) and a face shield and heavy leather gloves and boots. No water vapor explosions occurred. The wood mold did get cooked and the wood is destroyed in the process. IMHO, if you have a lot of knots, its not worth the trouble. There is a huge amount of heat given off by that volume of molten lead.
Having learned a lession the hard way, my second time out, I followed the recommendation of a neighbor who has done some serious foundry work. He recommended that I use a cement mold. A cement mold is quite insulating, it allows slower cooling of the lead. Briefly, I made a male pattern, out of wood, waxed it with paste wax, put it in a box, and rammed a cement mixture around it. (If you want more details, I'll post them in another reply with picts.) I waited a week for the cement to set up and removed the pattern.
Mr. Helpful Neighbor also lent me a propane torch that is connected directly to a propane tank. This was a two hand model with no regulator, it has quite a flame :cool: ! I lit this baby with the cajun cooker burner under the lead pot. This torch enabled me to direct all those BTUs to where they need to be. I was able to quickly melt a significant portion of the lead in the pot, preheat the mold and the shortened pipe from the lead melting pot.
The melting pot was 1/2 of a 55 galon steel drum. It was lent to me by another boat builder who used it for a Haven 12 1/2 keel. My 750 - 800 lbs of lead filled the bottom of the drum to a depth of 7 or 8 inches. I positioned the pot directly over the mold so the flow of molten lead was straight down through a 1 1/2" flange bolted to the bottom of the drum and a 6" long nipple.
It took a day for the lead to cool in the mold. (The thickest portion of my keel is only 5" thick). The wood box was removed from the cement mold and the cement broke away easily whth a couple hammer taps.
Since you have not the lead for the keel yet, investigate the Automotive Battery recyclers. They pour lots of lead and it could save you the hassle of cleaning up 900 lbs. The process of cleaning up the lead is a good primer for pouring the keel if you choose to do that.
I don't want to discourage you, just inform you of the pitfalls I encountered.
Good Luck, Work Safe!
05-28-2002, 02:40 PM
I may be missing something but you have a stack of 2X's with a cavity the shape of the keel cut out of them?
What keeps the lead from creeping out of the joints every 2 1/2 inches? 900lb of molten lead will have a lot of pressure on those joints. :eek:
You need a male mold around which to form a well packed casting sand female mold. And you want continuous pour - no cold (discontinuous) joints.
Art - I don't know how to place one of direct, go from here icons, but you should check out Mad Dog's website before you pour your keel. He has recently posted a similar project along with some non-traditional solutions. try: www.nauticalfollies.com/ (http://www.nauticalfollies.com/)
05-28-2002, 07:48 PM
The Anchor the man has cut from a piece of large I beam is interesting . Can this possibly work ?
David Tabor (sailordave)
05-28-2002, 07:50 PM
Art, it's been a while since I checked out this guys web site, but one night on the mid shift when it was slow I found his site. It's really quite good and he goes into a lot of detail about the lead keel pour. check it out and I'm sure he would answer you if you emailed him your ?'s.
Good Luck, David
05-28-2002, 08:22 PM
Glenn Ashmore is a brilliant gem! He helped me when I was messing with lead the first time. Nothing as big as this yet...
Unless, he's sailing the new girl, Rutu, he'll answer your questions with some authority.
[ 05-28-2002, 09:23 PM: Message edited by: Sailing-Randy ]
05-29-2002, 03:14 PM
I used an old air compressor tank with plumbing attached to the air outlet. I ran a threaded rod through a nut welded above the hold into the melt with a plumb bob on the plug end into the drain hole. Definitely bury the mold...make sure your lead has 4% antimony (I think its antimony...is that right guys?)... the antimony adds strength, otherwise the lead is too soft and the whole keel will bend too easily. Wheel weights have it...xray shielding doesn't...I don't know about battery lead but I would'nt trust it. Steel drum...to scary with the the way those seams might bust open.
What else...Oh! The worst idea I've heard here is bailing the lead from the melt to the mold. This is a recipe for disaster...serious injury. I say definitely plumb it, open the valve and stand back.
Also, have a friend video the whole process. Keel pouring was one of the best days of my life and I watch the video way more than I ever watched my wedding video.
05-30-2002, 02:32 PM
Thanks again for all the input, folks! I'm sort of putting this all on "hold" while I gather a bit more information and locate "materials". But I appreciate all the advice. Keeping busy in the meantime "tidying up" my hull's planking seams and generally getting the topsides prepped for the first of the "finish" coats of Kirby's finest "Steamship Black"...
Here's a picture I took of the construction plan that I have hanging on the shop wall to give you a basic idea of what I'm trying to do here... I'll post pictures of the mold for your "consideration" as soon as I get my next roll of film back... You should be able to at least see the general outlines of the ballast keel here though.
[ 05-30-2002, 03:33 PM: Message edited by: Art Read ]
05-30-2002, 03:06 PM
One more note; you don't need a valve per se in the your output line. Make a 'swing valve'. This is 1 or 2 90 degree ells in the outlet near the tank. While the lead is melting, swing up your outlet pipe so it is vertical; no lead can flow. When you are ready to pour, swing it down (DON'T do this by hand - use a long forked stick or equivalent). The lead can now flow; you probably will have to heat the pipe to get things started.
1 or 2 ells determine whether there is a 90 degree bend in the pipe, or a jog. I had just one. Tighten just hand tight - you don't want to wrestle, and the joints won't leak enough to matter, since they will be a labyrinth seal.
05-30-2002, 11:03 PM
Art, plaster of Paris will seal/fair the voids etc.
05-31-2002, 10:09 AM
I don't know what the prices may be like, but you should give a call to Non-Ferrous Metals (206-762-3600) to see what they may have. Recently I needed to make weight bags for a project and found they were the only place you could still buy lead shot. They had new shot as well as shot that had been mined out of old skeet ranges with the latter being much lower priced. They are a dealer and are getting their cut, but may have a scrap rate that isn't too bad.
06-05-2002, 10:42 PM
Well, my parents, having gotten wind of this little lead pouring scheme of mine, have made it known, (in no uncertain terms!) that one: they've decided on just what they'd like to "contribute" towards the boat building project, and two, that they INSIST I get someone else to do it! So... Any recomendations on a local foundry will be given a bit more serious consideration now. Also, I'm wondering if I'll be able to use that female mold I made with a foundry or if I'm gonna need to make a male "plug" now? (Do we ever really "grow up"?)
06-06-2002, 12:21 PM
I checked with my buddy and the small foundry he knows about just seems to do bronze, but I will check a little farther. Frankly, as exciting as pouring sounds, it's one of those things that I wouldn't mind leaving to someone who's done it before. Molten heavy metals aren't something I'm equipped for at the moment. Give a cheer to M&D and let's find you a foundry.
06-06-2002, 02:01 PM
Since you are going the foundry route, I'll put in a plug (no pun intended) for the guys who poured mine.
Metalex Products, in Richmond (suburban Vancouver, BC) 1-604-273-5487
They can vary the antimony content to your requirements, and were unfazed by my wooden female mould. I've no connection with them, other than the 'satisfied customer' thing.
Maybe cross-border keel transportation isn't something you want to get into, but geograpically it isn't far - and there must be something similar on your side of the line.
06-06-2002, 03:45 PM
Originally posted by DerekW:
Since you are going the foundry route, I'll put in a plug (no pun intended) for the guys who poured mine.
Metalex Products, in Richmond (suburban Vancouver, BC) 1-604-273-5487And you get to pay in Canadian dollars.
Art, give Ballard Brass (close to Hales and PIRATE) or Irish Foundry (they're on 1st Ave. South if I remember right) a call. And give mom and dad a big hug for this contribution.
[ 06-06-2002, 10:09 PM: Message edited by: RGM ]
06-06-2002, 11:36 PM
Well, the 2 founderies that I contacted said that they would not alter the settings of their furnace.
Maybe M & D have some influence there? :D
Hope so, it would be easier, eh? smile.gif
06-07-2002, 07:07 PM
Here's my experience casting a lead keel for our 38' Bill Atkin design.
The lead keel for our boat is not a simple slab sided, flat topped affair. Instead it is all curves on the underside with a short flat top and a long taper aft that matches the wedge shaped deadwood. I made a wooden plug, layer cake style, fairing it up with a variety of power tools and drywall crack filling compound. The textbook amount for shrinkage was allowed fore and aft but not athwartship. The finished plug was about 14’ long and needed several people just to move.
The next step was to build a big plywood box that looked like Frankenstein’s coffin. The plug was suspended in the box and concrete poured around it to create a female mould. In hindsight, it was grossly overbuilt with almost a foot of concrete in places and rebar throughout. I didn’t fancy the idea of 10,000 lbs. of molten lead running over my feet so stuck with the “more is better” theory.
The design weight of the keel was 9500 lbs. And I had about 11,000 lbs. of miscellaneous scrap on hand, including old sewer pipe, roof flashing, wheel weights and ballast pigs. I had intended to weigh and tally each piece as it went into the pot but forgot in the heat of the moment, so the best estimate of the final casting based on what was left over is 10,500 lbs. The plans called for 1,000 of inside ballast so the discrepancy seemed acceptable. Somewhere I read that most keels are overweight anyway.
I perched the fabled cast iron bathtub on 45 gallon drums, arranged a drain into the mould (using elbows and a swing arm as the valve) and put two big propane space heaters on end like rocket engines under the tub. Three large hand held “tiger” torches completed the heat generation equipment. A test run with a couple of hundred pounds of lead seemed to indicate that the rig would work and the tub would not split asunder when heat was applied. On the appointed day we loaded the tub with lead and fired up the torches.
My friends had divided themselves into two camps: those who wanted to see this happen and those who wanted to be in a different county. Some of the former group, equipped with heavy gloves and face masks, helped to slog lead up the ramp to the tub, held torches and watched as molten lead poured out in a clear silvery stream.
We burned about 400 lbs. of propane but didn’t generate quite enough heat to create a steady flow of hot lead resulting in imperfect bonds between layers. However, the lead keel is held on with 14 one inch diameter bronze through bolts, and seems unlikely to either fall apart or off. I have not spend much time worrying about it.
The keel casting lasted until midafternoon and ended with large quantities of cold beer for the crew, laughter and congratulations that no one was hurt.
The denouement, of course, was removing the keel from the mould. I rented a jackhammer and spent several days of hot, dirty and noisy labour reducing the concrete mould to a pile of rubble and annoying our neighbours. I don’t recall reading about this part of the process in the “romance of wooden boat building” articles in WoodenBoat Magazine. Perhaps I missed that issue.
In hindsight I think that a keel of this size is at the outer limit for a backyard project. A 2 or 3 thousand pound casting should present no serious problems, but the set up cost and hazards of a 10,000 lb. casting are problematic. I could have hired a professional to do the job for 50 cents per pound, lead not included, which might have been money wisely spent.
At the risk of dwelling too long on the subject, I will refer to briefly to the bolt holes in the lead. I put wooden dowels in the keel mould in an attempt to create bolt holes. In practice it didn’t work very well. The dowels were badly charred with flames from the torches as we tried to keep the lead moving, so the holes were either very rough or non existent. Once the lead keel was maneuvered into position (a temporary cradle, short pieces of pipe as rollers, two little hydraulic jacks: next project is to build a pyramid!) I bored up through the rough bolt holes into the wood keel and down through the wood and lead for the rest. I had a long extension welded to a 1” twist drill bit for these holes. My concern was that the bit would get hot, bind in the hole and freeze up forever. It did tend to clog and bind in spite of water or oil poured in the hole (both of which make a big mess as cuttings come up). Once it got away from me, the bit froze up in the hole and the drill started turning, stopping only when the power cord was sheared off, fortunately without breaking my wrist in the process. Make sure your finger stays away from that trigger lock button! Next time I’ll try an auger bit instead of a regular twist bit as it might clear itself more easily.
In the end, 14 one inch diameter bolts were set, a row up the centre line with matched pairs on each side of the centreline where the width of the keel permitted. The top washers tended to sink into the the wood keel so I made 4” diameter washer shaped pads from black locust to spread out the compression load.
Kids: do not attemt this at home. If the Department of the Environment doesn't get you, the Department of Labour surely will.
06-08-2002, 02:55 AM
Wow, Wilson. I'm begining to think that's one experience I won't regret missing "too" much! ;)
Just to bring this up to date, I visited the foundry today with my wooden mold to see what they thought. FYI, every place I was able to contact under the "Foundry" listings in the yellow pages, (including Ballard Brass, I still haven't heard back from the folks at Irish...) said they don't "do" lead. But I DID find Non-Ferrous Metals in South Park listed under "Lead" and remebered Jaime mentioning them. They were happy to talk with me and said they could cast it right on site. The guy I met when I went there didn't seem too alarmed by the mold. In fact, he seemed pretty "blase" about the whole thing. "A little pour like this shouldn't be any problem..." He suggested they'd probably want to coat it with graphite(?) beforehand and told me the refractory cement I proposed sealing and fairing it with should be fine. The price, at $.70 a pound startled me a bit until I realised that was including both the lead AND the casting. $.40 a pound with my own lead. For thirty cents, I think I'll forgo scrounging, cleaning up and delivering to them all those wheel weights! Thanks again for all the input, folks. One last question... 4% antimony, right?
06-08-2002, 11:52 AM
Hot dog Art, .70/lb sounds like an absolute bargain! I've certainly enjoyed working with the NonFerrous Metals folks on the little bit of lead buying I've had to do. I must say, I like to save my serious learning curve experiences for things that I really want to know about. Pouring lead sounds like something I'd like to watch be done by folks who already know their stuff. Especially after hearing Wilson's tale. That sounds like work! :eek:
06-21-2002, 02:49 PM
Well, I just got back from the foundry. The new ballast keel is cooling down as I type. Pretty amazing to watch. They just slid my mold next to a huge, (3 ft. deep by about 5 or 6 ft. around!) gas fired crucible filled with already melted lead. Then they dipped a "bucket" hanging from a powered chain fall into the crucible and swung it out over the mold. I'd designed the mold so that the faying surface between the deadwood and the ballast keel was level and flush with the surface. Then, after fitting the two sides together, I just built up the bottom with some "athwartship" timbers to provide a nice stable, base. The interior surfaces were given a couple of coatings of "refractory cement" to smooth out the joints and fill any gaps. Worked a treat! I did the individual sides first, then faired in the joints and the bottom after assembling it. I would have never guessed that the "cement" would sand smooth so easily! I forgot to ask today, but when I dropped the mold off earlier this week, they said they'd probably give it a coating of graphite as well.
It took between 2 and 1/4 and 2 and 1/2 "buckets" to fill the mold at 335 lbs. each. So at least now I finally know about how much my ballast weighs. 'Bout a hundred and fifty lbs. less than I'd guessed... The whole thing took about two minutes. They spent about ten more leveling off the surface as it cooled with a little "dipper" and a welding torch. That was the only time I saw flames on the mold. The torch set fire to the wood in a few small areas such as the hard corner where the top of the mold met the ballast and some unprotected spots on the cross "battens" I used to tie the two sides together at the top. I'm glad I finished off the last of my "refractory cement" by coating the top, horizontal face of the mold. Quite a bit of lead "dribbled" across it and he was plying that torch pretty "casually".... But the flames never really had a chance to get going, they just left behind a little scorching here and there. There was quite a bit of smoke seeping out from the seams of the various "layers" of the mold and I saw one little "eruption" of molten lead at the top edge of the keel a few minutes after the initial pour while they were still leveling it off. They "jumped" a bit, but didn't seem overly concerned... After examining it when they were done, I couldn't see any evidence of leaking. One joint without a lot of "depth" to it had a bit of lead peeking through but that's about it. I almost think I could re-use that mold if I wanted to.
I'm still going to have a bit of work left drilling for the keel bolts, fairing the faying surface and triming the bottom edge flat. (The bottom of the mold was left "stair stepped" to get the right angle. I figure the offcuts there will make for nice trimming ballast if I need it, and it was sure easier than shaping the bottom of that mold to suit...) But I'll wait to bug you all about how to best go about that until after I pick it up. That should prove an "interesting" exersise all in itself! The pictures are already off to the lab and I'll post 'em here after I get back from the class I've got to teach next week...
Boy, that was fun! Great "guy stuff"... ;)
[ 06-21-2002, 10:53 PM: Message edited by: Art Read ]
06-21-2002, 03:55 PM
Art et al. a regular metal drill bit should have its cutting edge reground for drilling lead.
I don't have the exact angle handy but Machinerys Handbook should have it.
I can't stress enough the value of having a copy of that book around your shop or in your library.
I have said before you don't need the latest version a 10 year old one will work for what we boatnuts need. Hit the used book stores and on-line seller for one.
Pipe threading liquid or Lard or Tallow work well as lubricants for drilling in lead.
As with all deep holes don't try to drill full size right off the bat. Start with a drill about 50% of finish size and work up from there.
Much less chance of the bit grabbing or worse freezing in the hole.
Am I making any sense here???
06-21-2002, 04:48 PM
Thanks, Dave... I'd never heard that. Actually, my initial game plan, once the deadwood and ballast keel are ready to fit, is to start the bolt holes thru the floor timbers and the "sprung" plank keel, and then on into the first few inches of the deadwood from above. That should establish the drilling angle. Then I'll probably roll the deadwood/ballast keel out from under so I can get at it and will have a somewhat shorter distance to go to finish 'em off. I'm even toying with the idea of "hiring out" that part of the job. As long as I get the holes started in the right direction with the "shortish" bits I already have, I ought to be able to find a local yard that would already have the proper "extended" bits, and more importanly, the experience, in drilling long holes through lead? (RGM?) I suppose it depends on just how akward this brute is going to prove to be when it comes to "manhandling" it around. 750 lbs. or so ought to be "manageble" with a dolly, a jack and a couple of gullible friends, no? (Jaimie? You listening? ;) ) Thoughts?
[ 06-22-2002, 12:30 AM: Message edited by: Art Read ]
Congradulations to you Art, deepest sympathies to Jamie, me and who ever else you talk into helping you drill, damn it. No problem really, lookin forward to it. No cheap beer though! Let's get together sometime soon and figure out what we'll need for drill sizes/lengths. I'll get them ground for lead. I know that we have some large ones already ground for lead, pretty sure they're to large for your job, maybe not? Is your boat upside down or right side up right now? Also we have a hydraulic platform/dolly that we can use over a weekend. It would work great for positioning and drilling your ballast. Give me a call or swing by the yard sometime.
06-21-2002, 06:11 PM
WOW! That sounds GREAT! (pitter, patter) Once my heart stops racing in gratitude, I'll try to figure out a timetable. I'll be "incomunicado" 'till next Friday evening, and won't be able to collect the keel 'till the following Monday. And I figure it'll take a while to sort out the as yet uninstalled, but finished, floor timbers in way of the keel and "clean up" the raw casting and fit it to the deadwood. Gives us a bit of time to plan... (AND put in your order for "prefered" libations!)
Just FYI, the plans call for 1/2 inch bolts with the longest being, at a quick quess without measuring it again, a bit less than three feet total. (Floor timber, plank keel, deadwood and ballast.)
(Oh. Guess I also better figure out how I'm gonna jack up the boat to raise the cradle's hull supports so there'll be room under there! It was nice having it low to work on the deck but it's quite a bit heavier now. Now you know why I made the legs of that cradle so tall... Here's a picture of how she sits as of now. I figure I need about a foot, maybe a foot and a half more to give me enough clearance to leave room to slide the tops of the bolts in there.)
[ 06-21-2002, 11:39 PM: Message edited by: Art Read ]
06-21-2002, 06:12 PM
Gosh, you Seattle guys have ALL the fun!
06-21-2002, 11:40 PM
Wow - reading this takes me back and makes me glad the gods moved as they did 8 years ago. I had collected about 8000 lbs of lead from tire stores over several months, melted it into lead "muffins" (ruined the pans for the bran ones) and had them stashed at the end of the boatshed in old 5 gal buckets. I'd been reading everything I could find on pouring large keels and had lofted the ballast keel, prior to making a concrete female mold - had even found a ratty old bathtub and assembled all the fittings. Then I found Fiona II in bare hull state (complete, of course, with ballast keel) sold the boatshed, sold the buckets of lead for twice what I'd paid for them to a guy up in Pender Harbor who was still in the dreaming stage, and decided I would NEVER smell melting lead again!!!!
I'm so glad you eventually got the job done without the hard work, and am awed by the description of what its like to do it yourself. And glad I didn't get to do it...
Congratulations to all of you.
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