Casting a lead keel, help

[Alan Jones]

I have to cast a 4.5ton lead keel and would appreciate any advice on how to do it.

[Art Read]

Any foundries located nearby? You could probably get them to pour it for you, with their lead and your mold, for not much more than the cost of scrap lead...

http://www.imagestation.com/picture/sraid24/p91922f8cb4df995926561d2ddd9b1343/fd984d30.jpg

[Thad Van Gilder]

When you make the mold, bury it up to the edge in sand. That reduces the risk of leaks. Also, if you use a bath tub to melt the lead, make sure whatever you use to move the lead to the mold is hot.

-Thad

[wyndham]

Thats a Sh*t load of lead to pour yourself. Find a foundry.

[Thorne]

What they said above.

There are also a number of threads and websites dealing with pouring smaller keels, so search this and other sites, particularly read the FAQ here.

[Bruce Hooke]

Are you doing the pour in West Africa or the UK? I'd imagine that in West Africa labor is probably pretty cheap, but if there are local foundries they may not have much experience with pours of this type either...

[gert]

This begs a question I don't recall seeing here;

Whats a foundry poured keel worth assuming one provides the "plug"? ballpark

[ 11-30-2005, 01:11 PM: Message edited by: gert ]

[ssor]

After you have it you have to be able to handle it. 9000 Pounds is not easy to push around.

[paladin]

thatsa a lotta wheel weights.....and you're gonna need a thousand pounds of linotype to go with it...

[ 11-30-2005, 02:10 PM: Message edited by: paladin ]

[TomHaven12]

Check out this web site:

http://www.rutuonline.com/html/the_keel.html

Everything you need to know if you do it yourself!

[seo]

What type of ballast casting? A long shallow shoe to bolt on the bottom of a schooner is a pretty simple thing compared to a 9-ton fin.
If it's the first type, you might be able to cast it in sections, maybe 3 pieces of a ton and a half each, which is pretty manageable. That's how at least some of the Maine schooners did it.
Right now, in the Northeast, the business seems to have been totally taken over by a single foundry up in Ontario that is reputed to do excellent work for a good price. But Uganda is a long way from Ontario...
The slickest keel pouring rig I ever worked with was a retired Coast Guard spherical steel buoy, maybe 36" in diameter. It had a hole cut in the top, and steel skirt welded around the bottom, and a riser pipe inside that stood about ten inches above the bottom of the pot.
Heat was provided with a regular old heating oil burner gun stuck in a hole through the skirt, with a smoke pipe on the other side. Once it was hot, lead was introduced until there was molten lead up to the top of the riser. Then every time you put fifty pounds of solid lead in, fifty pounds of molten lead overflowed into the riser pipe, thence through a pipe to the mold. There was a couple of elbows in the pipe that allowed it to be moved to direct lead here (or there).
The same system would work fine with a bathtub, but. Remember that the bathtub with eight inches of lead in it will be very heavy. And make absolutely sure of any fitting in the bottom of the crucible.
The crew I worked with once had a form break, and over a ton of molten lead just disappeared into the beach, blasting out steam as it went. Took days to recover it.
I would be very reluctant to pour out of a crucible into a pot and carry it around. Many opportunities for disaster.
The deeper the mold, the more pressure at the bottom. A simple trapezoidal shape can be poured into a welded steel or aluminum form, without trying to perfect your technique of ramming sand, etc, etc.
I'd be tempted to look aroud for someone who has had some experience. Or start out pouring some 90 lbs. ballast pigs. Good practice, and a chance to perfect technique.
seo

[DanO]

Check out my "thread" posted a few weeks ago:

Lead Casting (http://www.woodenboat-ubb.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=012680)

Dan

[AlanL]

Fella up in Kaikohe poured his keel in his back yard . Got a whole bunch of his mates around to help out and used the fire under the bath tubs to heat stones for a hangi (underground oven).

He dug a hole and built the mould in place. Positioned the baths either side so they could be over turned into it, lit the fires and waited, and waited until the lead melted. Poured it, ate the hangi and let it cool.

Then the problem. How do you get two baths worth of lead out of the ground, in the back yard :rolleyes: :D :D

Alan

[ 11-30-2005, 11:19 PM: Message edited by: AlanL ]

[Alan Jones]

Thanks everybody for your help. To answer a few questions, yes we are building in Nigeria which should put a few years on the timescale, would much prefer to have it done in a foundry but in Nigeria!!!!. To have it made overseas and shipped here will double the cost. I would think that the plug will be the most vital part of the whole deal and I am making that so I thought I might as well do the whole thing. Moving/lifting not a problem I have a truck with a 40ton Hiab on the back. The keel itself is a large fin with a slight flare/bulb at the base and the designers say it is to be poured in one go. As a mate of mine said cock it up, melt it down, start again.
Once again thanks to everybody Ill keep you abreast of the fun and games.

[John Turpin]

We want pictures. :D

[Dayton Eckerson]

Larry Pardey's book on building Talieson's hull has a ton of pictures and descriptions on the keel casting process. I think the title is something like "Details of Classic Hull Construction." It used to be an $80 investment, but I think the price has come way down now.

[Old Bingey]

I have a buddy who built about a 50' steel ketch... looked as big as a shrimp boat. It had accommodations in the keel for lead ballast. He was smart so he rigged up a big boiler looking thing on deck and braced it well and lagged it with insulation and concrete blocks and fired it with propane. The lead was in small blocks and it took a day and a night (and many 20# propane bottles) to get it all melted. He invented this valving arrangement where he had about six feet of 2" pipe coming off an elbow at the bottom of the tank. His plan was to melt the lead, then turn this pipe down and let the lead run out and lift the pipe to cut off the flow. But, when the lead in the tank was all melted, the elbow and about two feet of the pipe had cooled enough so when he swiveled the pipe down, the lead wouldn't run out. Not to be defeated, he fired up the big cherry on the acetylene torch and heated the pipe and elbow and, lo and behold, it worked and the lead ran out in a hurry. He had on his fireman's suit and scuba tank and asbestos gloves and had a handle welded onto the pipe and was all set to distribute all this lead through the bilges of the boat but when he tried to raise the pipe to shut off the lead so he could screw on a coupling and another joint of pipe to extend out to another section of the bilge, he found that he had "misunderestimated" what six feet of two inch pipe weighed when it was full of lead and he couldn't lift it... not at all. He shucked off that scuba tank and came scrambling out of there like a cat out of the toilet.

All that lead ran into the bilges of the boat. Fortunately, liquid lead is not very viscous and it was hot enough and massive enough that it seeped through the limber holes in the bulkheads and frames and leveled out exactly like it had been done by somebody who knew what he was doing. There were a couple of places where the expansion of the steel bulged out the box keel but when the lead finally cooled (days) it shrank back and the steel was annealed so well that he could beat the boat back into shape with a block of wood and a sledge hammer. You can barely see the waterline where the top of the lead is.

Be careful

[Alan Jones]

Once again thanks for the help, will post pictures of the pour so you can all see how not to do it!!
Thanks to Old Bingey that story conjours up all kinds of pictures but I guess that joking aside it is easy to underestimate what 4.5 tons of molten lead can do if it all goes wrong.

[Alan Jones]

One more question is it possible to cast the keel and incorporate the keel bolt holes at the same time. If possible it has to be easier than drilling 4ft long holes the a lead block.

[Andrew Craig-Bennett]

I have never done this, so my advice is worth little but I believe the answer is "yes". Michael Verney's books, "Complete Amateur Boat Building" and "Practical Repairs and Conversions" have a discussion of the processes involved.

[seo]

Not to harp incessantly on the Herreshoffs, but: their method was to drill and tap the lead casting. I believe the top of the casting was stiffened with extra antimony, and the depth of the hole was eight times the diamater of the bolt. (That is only my memory speaking. Don't rely on it.) Some of these boats had enormous keels: Reliance, built in 1903, had a 100 TON ballast keel!
Trying to cast your bolt holes as through-bolts requires an additional moving part to the process. If they come out crooked, you may have some real troubles bolting it up.
Sounds like casting a 9 ton fin keel with inexperienced help is going to be an adventure in itself.
Have you considered a welded steel fin? which could be built slowly, with lots of opportunities to get it right, then filled with lead?
The idea of pouring nine tons of lead in one shot, figuring that if something goes wrong you'll simply repour may be somewhat naive. That's a lot of molten lead, an exceedingly dense and dangerous liquid when it starts sloshing around.
seo

[tony morales]

"Bud McIntosh's book How to Build a Wooden Boat has a whole chapter with great illustrations on severel methods for both lead and iron ballast keels with cores for keelbolts. Available thru woodenboat store for $36.00 U.S. What design are you building and what are her dimensions? Can you post it here?

[Gary E]

Originally posted by Alan Jones:
One more question is it possible to cast the keel and incorporate the keel bolt holes at the same time. If possible it has to be easier than drilling 4ft long holes the a lead block.Yes, a core can do that, ask any foundry.

Are you telling us that the cast keel will be 4feet in over all depth and that the bolt must go all the way through?

If you want to use shorter bolts, pockets can be cored into the casting near the top and bolt holes can be cored to intersect the pockets.

I do not think I would core for the bolts. I think it much easier to cast the keel with the pockets cored, then position the keel under the boat in the proper place. Then drill the holes from the inside of the boat. This way all of them will line up with no problems.

[ 12-02-2005, 02:29 PM: Message edited by: Gary E ]

[Bob Cleek]

I've been lurking here with some amusement, though I shouldn't take pleasure in your distress. Melting lead and pouring it is not rocket science, but probably just about as dangerous. Common sense will prevent most accidents and when accidents do occur, it will at least provide an excuse.

The problem I see, however, is that you are planning to pour a fin keel with a bulb on the bottom. Think about it. You have no alternative I can see with such a pattern but to cast it in a split mold. The bulb will prevent casting it in an open mold. You will have to build a cope and drag and fill it with casting sand. You are contemplating a HUGE casting that will require a correspondingly large cope and drag and a lot of foundry sand. I'd think you will need an overhead crane just to lift the cope. Not to mention that such castings are tricky under the best of circumstances. As obsessed as I am with doing everything myself, I'd have to say that this sort of casting is really a job for a good foundry with the equipment to do the job right.

As for casting the keel bolts in place... don't go there. This is a common practice in production boats, but not good. I've cut up a number of keels for scrap which had bolts cast in place. In nearly every one of them, some of the bolts created voids in the casting, perhaps because of temperature differences or lack of adhesion between the metals. When a pour hardens and shrinks, the internal tension will rip the metal apart inside if there is a weak spot, such as created by the bolts. On one I cut up, three bolts had pulled loose because even though the ends were bent in an "L" to hold, there was only about an inch of lead tight against the top of the bolt and a void inside all around the bolt. Far better to pocket them. (Your keel is too deep to drill straight through... length of the bolts is a factor that affects their stretching under tension.) This method also permits replacement of keel bolts. Replacement of cast in place bolts usually occasions drilling new holes and installing new bolts anyway. As for tapping the ballast casting as LFH did, this works only for certain keel designs, such as Herreshoff's. If the ballast keel is long, you have a lot of space to set bolts. Your ballast is "high aspect" and you will have a more limited area to attach it. I'd pass on tapped keel bolts in this instance. (However, I'll defer to LFH if his plans indicate otherwise!)

[Columbia 112]

One piece, I don't think so. I've seen three piece high aspect ration fins for grand prix racers. Bronze upper section with a wide plate to attach to the paper thin hull then the fin section and finally the bulb on the bottom. All of these were bolted together. It's not rocket science, just an old boat.

Ross.

[Alan Jones]

To reply to the questions
1; Seo, the total weight is 4.5 tons
2; Tony, the design is a 46' cutter first designed in 1928 and built in 1930 by Laurent Giles in UK. The boat was called "ETAIN". I sailed on the boat in 1970 and fell in love with her. At that time she was at the end of her life but was still a joy to sail. I asked Laurent Giles if we could recreate her using modern materials and "EXCALIBUR" was born. We have tried to keep as close as possible to the original design above the water line but under she has been up dated hence the new keel profile.
The dimensions are, LOA 46ft 5in, LWL 33ft 4in,
BM 9ft 6in DRAFT 6ft 10in DISPLACEMENT 10tons SAIL AREA 833sq ft.

Rough keel dimensions are total length 11ft 11in,
width at widest point 17in Height at leading edge 32in taper to 26in to 14in to 10in at trailing edge. Because of the top profile it will have to be cast upside down. Weight 4.5tons.

[PeterSibley]

I'd say Bob Cleek's advice is as good as it gets.I'd like to offer something else but hes covered it all smile.gif

The URL that TomHaven 12 offered would probably be the best online advice I can think of,

http://www.rutuonline.com/html/the_keel.html

He uses chemical bonded sand, very good and very strong.Done within a welded up steel container and you should be fine.Melting that much lead is going to be exciting but its just the same job writ large.Good luck.Don't forget the protective clothing from your friendly local foundry supplies....for you and all the crew.