How To Repair Keel With Lead

Vasquez Armilgen02 · Friday 17 December 2021

repairing lead keel

ive read alot of posts on lead keels justed wanted some specific advice. ive bought an old small racing boat 24 ft that has an interestingly damaged lead keel it looks as though someone has taken a chain saw to the bottom middle of the keel.about 30 square cms has a gouged hole approx 5cm deep. the undamaged lead width is a minimum of 1cm at bottom and 4 cm at top of damage. (about 40% of width left) either side of the damaged area is 15 cms on the trailing edge and 10 cm on fron edge. (50% of cord at bottom 30% at top of damage. reading the threads i think the best solution is take of keel and recast. however the keel is attached very well to boat and is absolutely plumb and i dont want to risk what is basically sound keel. i dont want to fill with epoxy as want to maintaIN weight.
what i thought ide do is:
put the boat on its side, chain saw the damage out to a regualr shape (leaving the existing thickness on the other side as much as possible, cut notches under each edge of depression , put some brass (or other heavy alloy?) bar wedged under these notches across the depression, and then pour lead over the whole lot back upto top of hole, let it set and fair.
will this work? any issues on lead sticking in and on strength of keel, will lead pour round the brass and into notches ok without weakening airpockets.
this turned out longer than intended but excuse me my first post any advice most welcome,
james
Fill it with lead

Lead is pretty easy to melt/weld and while the details are a bit fuzzy in principle this is rather cheap/easy. Post some pictures and dimensions and there are a few others on the forum that as a group can fill in all the details. I melted 70lbs of lead the other day in an old cast iron cook pot on a propane backyard cooker (very heavy duty one). The melt went very very quickly and I did some test pours into tin cans and next week the test pours will be into wooden molds lined with a wash coat of plaster of paris. You could clean and rough and shape the void for maximum bonding/keying/interlocking and then preheat the surface wiht a torch and then slap on the mold and pour.
Also if the angles allowed you could drill and insert a few bronze pins that would join the parts after the pour if you are assuming that they would not be 100% fused/joined.
My lead melting is for additional ballast to fit in the keel voids of our steel schooner.
thanks not too concerned about pouring lead wondered really about strtength and all hanging together, dont really want to epoxy as estimate lose 50 odd kg, really concerned will the integrity of keel be compromised by patching with lead?
Welding is a viable option

Fumes and out of position are an issue but it is doable with a propane torch. I say that as some one who has worked as a shipyard/boatyard welder for 6-8 years some time ago and now have a home shop full of welding equip and will be tig welding some alum gaff jaw modifications this afternoon but has never actually/really welded lead. There is a member of the forum with lead welding experience who may chime in soon?
Please post a picture of the area of concern. (picture=1000words)
Before the days of Bondo, most auto body repairs were done with lead. Maybe find a body/fender person from that era? (On second thought, given how long ago that was and the fact that they worked with lead every day, ..........)
Originally Posted by George Ray

Fumes and out of position are an issue but it is doable with a propane torch. I say that as some one who has worked as a shipyard/boatyard welder for 6-8 years some time ago and now have a home shop full of welding equip and will be tig welding some alum gaff jaw modifications this afternoon but has never actually/really welded lead. There is a member of the forum with lead welding experience who may chime in soon?

Please post a picture of the area of concern. (picture=1000words)

I have experience with welding and lead.
Here is what i would do.
Remember a CUBE of lead 12 inches weighs about 760 pounds.
Drive screws or nails into the area that is missing so that when it is filled with lead ,the lead won't fall out.
Just box in the area that is missing with sheet metal like 16 guage.
Attach with screws and clamps too. Area underneath to be solidly supported.
Cut a hole at an angle downward in the lead just above the piece that is missing on both sides. Heat the lead up with a B3 propane burner which you can get at a ceramic supply store. You can use a 5 gallon propane tank. If the lead starts to turn gold colored it is starting to get too hot. Scrape off the slag before pouring. Wear protective clothing. Lead melts at around 900 degrees.Do a trial pouring with empty containers first to make sure you have the process all set up correctly. Stand up wind of any fumes and wear a mask.The pot of lead should not be too large. a steel pan with a VERY STRONG HANDLE.The pot could be about 9 inches diameter and about 6 inches high.You can't use a kitchen pan ! You will have to make a very strong stand so that you can place the burner underneath.
Pour the lead into the hole untill it fills. You cannot use a long tube to pour it thru because the lead will solidify before it reaches the place it is going.
Wish we could see a photo of the hole.
If you calculate that the weight of the lead and it is less than 50 pounds forget it. Just fill with epoxy.

I love the smell of fresh cut plywood in the morning.
Why not use epoxy mixed with lead shot? Use screws to secure it as was mentioned before. That would get the weight so close it wouldn't matter.

Will
Been there, done that

The damage sounds like grounding damage. Unfortunately, I'm familiar with this kind of damage, as Ceol Mor survived a grounding in 2001 and suffered this kind of damage.
I used both kinds of repair mentioned. It's quite remarkable how well epoxy adheres lead, particularly lead which is damaged and has a very rough surface. I wouldn't hesitate to repair all the damage with epoxy putty.

I did recast the trailing edge of the keel in place. It was badly bent, and I simply cut about 3" off, screwed in a bunch of bronze screws to help retain the lead, made up a sheet metal form clamped to the keel, and poured in molten lead. It's stood up ever since.

So I'm confirming the earlier post about screws and sheet metal, which I know works. There is one danger - it tends to warp or deform under heat, and all the lead may run out.

I think the melting point of lead is more like 700 degrees than 900, and if you use old wheel weights it is lower still. It is, however, seriously hot and dangerous. Make sure, if you go that route, that there is no chance of being injured if the lead runs out of your form.

If it were me, I'd repair it with epoxy putty only. You could add lead shot, if you can get it; don't use steel shot - it will rust, swell, and the repair will fall apart.

You can work out, very roughly, the weight of the lost lead; if it's only a few kilos, I'd let it go.
thanks filling with lead seems way to go, will the fact lost 40% odd of width and then repour lead on top affect strength of keel? will heating up hole to help bonding of pour possibly make other side bow, if i support it strongly underneath is that enough. the sheet metal is that clamped round edge of hole to stop spill does the edge between new pour and old lead in effect weld into new solid or will there be an obvious seam? sorry to keep asking but worried about loss of strength.
With lead rod (auto finishing) you can pre heat the damaged zone and slowly build up the gouge. Takes a little finesse but if your handy with a torch its not so bad. Slow and steady wins the race here.
The bond will never be as strong as a fresh pour but if you blend well at the start and make sure the base is good and soft you will get good adhesion as you work in the rod. Make sure you clean out the gouge well and rough it up. pre heat the area you will be working and melt in the fill. Work back and forth along the repair and build up slowly.
It's a little difficult to picture the damage you describe, but if you main concern is about the strength issue, I'd use the screw/thickened epoxy method with bits of tire weights or lead shot included. That's what I've done on my keel. The bottom of the keel isn't a structural strength member, it just hangs down there for ballast and shape.
Are you a racer and concerned about one-design issues? If not, you may be 'overthinking' the solution to this problem.

�Eventually, all things merge into one, and a river runs through it. The river was cut by the world's great flood and runs over rocks from the basement of time. On some of those rocks are timeless raindrops. Under the rocks are the words, and some of the words are theirs."
Just give us a photo so we can see what we are talking about.
Not metric measurements.
Go to tinypic dot com and click on upload. There is NO SIGNUP.
then after it uploads copy the html and paste into this forum.
Its that easy. Pick the middle one shown.

I love the smell of fresh cut plywood in the morning.
Metal screws or steel fasteners should do the trick. Leads are so far back
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thanks for all this cant send pictures as away from boat for few weeks, if anyone still listening a couple of last question if i put in some screws to the hole, pre heat the hole and pour in the lead will there be any chance of the keel flexing and the seams opening up or will it in effect weld along the edge. if i heat up the edge of the hole and the basis to help bonding will it allow the keel to bow or bend? will i have to heat it so much to try and achieve a "WELD" that distortion of the keel is possible(50% of the keel is left) last one a friend says he has some tungsten bar that i could inbed into the lead which will provide strengthening. is this right will this improve the situation
james