With each of my Boaterfly Projects in various states of destruction and reconstruction, Andrew felt he had enough keel bolt strategy thinking time. He’d made his decision about how to take my old bolts out and put new ones back in.
Option One – Sand Casting
Before we’d hauled out, we narrowed the options down to two. First, we could, theoretically, lift my keel into some transport vehicle capable of moving 9,000 lbs from the boat yard to a metal foundry on an island about 60 miles South of where we are. There, they could, theoretically, build a sand cast (big mold made of sand) around my current keel to match it’s exact shape. Then, they could insert new keel bolts into the cast and pour 9,000 lbs of new lead in place, like my original manufacturer did, to build an entirely new keel. Alternatively, we could melt my old keel until the lead turned to liquid, pluck out the old bolts and replace them with the new bolts. While in some ways this sand-casting process seems easier, it would be significantly more expensive to pour a whole new keel. It also seems more risky.
From our early research to just “buy and ship” a new keel, we had already learned that Valiant no longer has the mold that originally made my keel. There is no way to simply make me a new one that would match my old one, without using my old one as a model. So, if my keel got damaged in transit before the foundry could make the sand cast mold to its shape, or if the sand cast broke after Andrew melted my old keel, we would be up a creek without a…keel mold. For this reason, Andrew leaned toward option two.
Option Two requires Andrew to melt the keel-lead away in several small channels just large enough to allow Andrew to remove each old keel bolt one at a time, leaving the rest of the keel-lead intact. Then, Andrew will replace the old bolt with a new bolt, and melt lead to surround and secure the new bolt in place.
What could go wrong?
There are a list of doubts people have posed when Andrew describes this as his intended plan.
(1) How do you make sure the keel doesn’t lose its shape?
(2) How do you know the new lead you melt back into place will adhere to the old lead around it?
(3) How are you going to make sure the new bolts are placed at the exact same spot and angle as the old bolts so that they will fit into the holes on the bottom of Sonrisa’s hull again?
These are all excellent questions Andrew wanted to be sure about before doing anything drastic. Having nothing else to go on, Andrew started perusing YouTube to see if he could find videos on lead melting/casting. As luck would have it, there are a lot of people who need to melt lead on their roofs, pipe organs, and casting bullets for guns (God Bless ‘Merica!) In these videos, Andrew learned quite a lot about lead welding, but there is no substitute for practice.
One morning, Janis Jalopy delivered a chipper Andrew to the foot of my hull. “Good Morning, Sonrisa!” He calls out to me. Are you ready to try this thing out!? He holds a contraption with multiple gauges and hoses, a trigger handle, and a pointy nose. “It was only twenty-five dollars!”
He drags two large tanks from Janis Jalopy’s trunk and sets about screwing the contraption to the tanks. He pulls out a rice bag drooping at it center with 100 lbs of lead fishing weights. He scoops handfuls of them out at a time and drops them into a stainless-steel cooking pot. Donning a face mask and respirator that makes him look like a weird Astronaut, he ceremoniously lights the torch. With a pop and a hiss, the torch throws an orange flame, then tightens to white blue stream. He aims it in the pot at the fishing weights. Almost instantly, they melt into a puddle of toxic liquid lead and swirling fumes. He inserts a bolt inside the pot, holding it upright with a pair of pliers. He flips off his torch, lets the lead cool, then dumps the now hardened puddle/bolt out of the pot and onto the ground.
“Well, Sonrisa, here goes nothing.”
Relighting his torch, he adjusts the flame and takes aim to the furthest outside corner, sweeping downward until the lead started falling away in sheets of dripping metal. With each swipe, he’d move the flamed closer to the center of the block, toward the bolt he is aiming to melt out. I keep a sharp eye on him. My biggest worry with this whole idea of melting my bolts out is that he will get a little over-zealous and melt out huge, uncontrolled holes in my keel until the shape is nothing like it was before. As far as physics goes, sailboats are really just airplanes tipped onto their sides: one wing poking into the sky (my sails) and my other wing gliding through the water (my keel). So, the wing shape of my keel is very important.
“I know, Sonrisa…that’s why I’m practicing making the smallest channel possible.” He says through his respirator vents. I must have been thinking aloud. He snaps off his torch, lays it on the pavement, then backs away arms akimbo. Together, we survey his first bit of melting work.
On this first melt, the channel is narrow near the bolt, but then splays wide toward the outside. I’m a little worried about this because in this practice scenario, it’s just a little block of lead. The keel requires him to melt a channel of up to four inches deep toward the center of the keel, and sixteen inches long from top to bottom. It could be exponentially more lead out of place. He melts his practice block into another big blob and does it all again. And again. He realized the small practice block is getting so hot that the whole thing is getting soft and losing its shape. As a result, the channels are large and wedged shaped. He runs to Multiquip and buys a temperature gauge gun. With the addition of this tool, he can melt away some lead, test the temperature, and if the remaining lead is too hot, he can wait until it cools down. Soon, he’s whipping out straight, narrow channels like it’s no trouble at all. This practice helps him solidify his strategy for protecting the shape of the keel.
As Andrew worked, he developed a system for catching the molten lead in the bottom of a cake pan tipped at just the right angle. The lead slides down into the corner and makes a long, narrow, easy to handle ingots.
Next task, to put that block of lead back together again in a manner that (a) sticks and (b) looks smooth. Andrew takes a sheet of stainless steel and tacks it to the side of the intact part of the lead block to form a dam. Holding a lead ingot in his left hand, he uses the torch in his right hand to warm the sides of the intact dam, then melts the ingot until he has a puddle of molten lead….
…which is leaking through the dam at a rather speedy clip.
“Hm.” I say. I imagine my whole keel melted into one big modern art piece entitled: “Sonrisa’s Big Puddle.” Andrew melts his practice blob and starts over. Cutting the channel, tacking up the dam in a different way, melting the ingot. This time, things stay together just long enough for the whole thing to cool. “That’s ugly.” I say.
Andrew nods and scowls. “We could use the wire wheel to sand it smooth, I think.”
He practices again and again. He learns to prepare the outer edges of the intact metal before melting in his ingot. He learns to use the trigger of the torch to add oxygen to the flame and “blow away” the black bits of oxidation that float to the top of his lead puddle. And, he improves his finesse at warming the keel-lead around the channel to just the right temperature to get the melted lead ingot to adhere as it fills the channel back up.
“You better test it to make Leslie’s Dad happy.” I tell him. Leslie’s Dad has been fretting about the second most common question: Will the melted and re-melted lead adhere properly to the cold lead left in place? Daddy-O imagines us sailing along in the Indian Ocean only to have the majority of the keel break away and plop off leaving only 15 keel bolts surrounded by little blobs of the newly melted lead.
Not to worry, Daddy-O.
Andrew lays into his block of lead with a sledge hammer and his Incredible Hulk hammering muscles to see if he can break it apart. “SMASH” … “SMASH” … “SMASH”! Everything holds together, and only dents instead.
The last major conundrum we need to solve is: how to make sure the bolts return to their rightful place. Since the keel has 15 bolts, this isn’t as challenging as it might at first seem. Andrew built a jig out of old angle iron and pipes. First, he found a 3/4inch diameter pipe and cut it into fifteen pieces, short enough that my remaining intact keel bolts will poke out the top. Andrew slipped each of those pipe pieces over the top of each of my old keel bolts. The outer diameter of the pipe he placed over my keel bolts was small enough to fit through the holes in my hull where the keel connects to me, so as long as the new bolts fit into the pipe, there should be no reason they won’t fit in through the holes in my hull.
Then, Andrew hired the welder at the boat yard to weld his leftover pipe and some angle iron he found in a scrap heap along the length of my keel from back to front, then front to back again connecting to each of the pipes slipped over the bolts. Andrew takes my old keel bolt nuts and tightens them down over any of the bolts intact enough to poke out of the top of the jig. I think this is a good solution for making sure the jig doesn’t wiggle around and change locations without us realizing it. Now, we have one big jig, connected completely from back to front. This fully connected jig will make sure that all the bolts are in the same place relative to each other. The pipes will make sure the new bolts will sit at the same angle the old bolts use to sit. Andrew steps back and surveys his work.
There is no problem that can’t be solved with a little research, practice, and creativity. That’s what I say.
Keel Bolt Repair
Melting Strategy Technical Synopsis
Strategy: He is going to melt out each keel bolt, individually, and replace all of the old keel bolts one at a time with a new bolt in the same diameter and “J” shape using Silicon Bronze 655 Alloy.
Q: How is he going to melt out the old bolts without impacting the shape of the keel?
A: (1) free the bolts through channels melted in a shape and depth as small as possible; (2) never take too many bolts out in any one place at the same time; (3) use a thermal temperature gun to monitor the material surrounding the channels to make sure the larger part of the keel never got close to the melting temperature for lead (which is only 327 C or 621 F).
Q: How do you make sure the new lead will adhere to the larger block of the keel left in place?
A: (1) Prevent or remove oxidation by chiseling way any oxidation on the surface of the intact keel and using the oxygen part of the oxy-acytalene torch to blow away oxidation that floats to the surface of the melt puddle. (2)Make sure the lead being melted back in contains approximately 5% antimony. Antimony is an element that when combined with lead and heat makes the lead 4x stronger than lead alone. And (3) melt new lead to the rest of the keel using the “puddle-to-puddle” technique. This means Andrew will heat and melt a small layer along the side/bottom of the cool, intact lead as he re-melts his lead ingot into place to fill the channel. So long as melted lead is touching incrementally hot-cold intact lead, it all should adhere as good as new. Third, the lead being melted should be 95% pure lead, 5% antimony.
Q: How do you make sure the new bolts will be in the same place/angle as the old bolts?
A: Build a jig that holds all the bolts in place both in relation to each other, and at the same vertical angle the old bolts were in.