Lead Ballast Failure

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Lead Ballast Failure

Postby Mike&Laura on Fri Jul 15, 2022 10:12 pm

We were finally at the point where we were ready to add the lead ballast to the keel. Instead of doing it ourselves we found a company in Seattle that works with lead and has a lot of experience pouring ballasts. We took the keel to them with all the other materials used in the instructions (cinder blocks, clamps etc). We discussed the instructions with the guy and even left him the book to reference. They were confident they could do it without any issues. They set everything up and began to pour the lead into the center compartment. He said that when it was just about filled, the adhesive failed and lead started pouring out the bottom. Once most of it drained they let it cool and tried again and this time it poured out the front and back and the next thing he knew the whole thing came apart. Now my keel is in two parts with the inside panels of the keel scorched and warped. Has anyone had similar issues? I’m just trying to figure out what went wrong and how am I going to fix it.
Mike and Laura
Port Angeles, WA
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Re: Lead Ballast Failure

Postby Dmitriy on Sat Jul 16, 2022 12:20 am

Hello! Don't be sad that it happened. Find the strength to start again and think that the new option will be better.
I think this is because the epoxy softens with heat, and the large volume of lead stays hot for a long time. It would be nice to see photos of the damage. However, I believe that it will be necessary to change the keel sides and everything connected with them. You also need to carefully examine the CB trunk, if it is not damaged, use it. I poured lead in portions. In the rear compartment made about 4 fills. This helps the lead cool faster and doesn't damage the glue.
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Re: Lead Ballast Failure

Postby Dmitriy on Sat Jul 16, 2022 12:24 am

Bricks pressed against the sides also help keep the heat out. And you can put clamps on the bottom where the glue line goes.
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Re: Lead Ballast Failure

Postby doug@dougbraun.com on Sat Jul 16, 2022 9:26 am

If the keel sides are not firmly supported with cement blocks, etc. the outward pressure of the heavy liquid lead will
definitely stress and deform the wood.
Also, when I was melting my lead, I used a high-temperature thermometer, and I noticed that once it is melted, the lead
will rapidly increase in temperature if the burner is left on. It could be easy to accidentally heat the lead 100 degrees or more past its melting point,
which could definitely damage the wood or epoxy.

I did 3 or 4 pours (I had only a normal size saucepan to melt the lead in), and it all went very smoothly.

Doug
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Re: Lead Ballast Failure

Postby Mike&Laura on Sat Jul 16, 2022 2:54 pm

Thanks for the replies Doug and Dmitriy. It makes a lot of sense that too much lead all at once would be the culprit. I've started to dig into the damage to see the extent. Unfortunately, it looks as though the bottom blocking is burned about halfway through. If I were to sand that down to remove the damaged wood, I may be able to graft in a piece to replace it and save the tail end of the keel. I've also cut off the sections of the keep panels from the ballast compartment. The lower part of the trunk blocking also suffered some burn damage and the trunk panel has separated from the blocking about half way up the back of the trunk. I may be able to epoxy that back together and add a 5/8 block to cover and seal the burned blocking on the lower section. It would take up a little space in the ballast compartment, which means I would loose about 5 lbs of lead. Of course the big concern is if all these modifications will affect the integrity to such a degree that I would regret it later. Right now, starting over seems like too much of a set back. Take a look at the photo and see what you think.
Attachments
IMG_0173_small copy 2.jpg
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Mike and Laura
Port Angeles, WA
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Re: Lead Ballast Failure

Postby doug@dougbraun.com on Sat Jul 16, 2022 8:51 pm

To get that much charring, they must have heated the lead WAY over its melting point. Maybe this is standard practice for filling a complex mold made of metal or cement, where the lead has to stay liquid long enough to completely fill the space.
BTW, did you coat the inside of the keel with epoxy?

Here is a closeup of my lead pour. Note the almost total lack of charring.

PXL_20201212_211052491.jpg
PXL_20201212_211052491.jpg (127.3 KiB) Viewed 241 times


Doug
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Re: Lead Ballast Failure

Postby Dmitriy on Sun Jul 17, 2022 12:06 am

Hmm, looks serious. I agree with Doug - I didn't see any charring, when I poured lead either. There was a lot of smoke, but no charring.

In this case, you can try to restore, but it will be necessary to clean and sand the parts well before gluing. This can be tricky in some places. In my opinion, the complexity of the repair is comparable to the manufacture of new parts. In any case, I wish you success!
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Re: Lead Ballast Failure

Postby Hooky on Sun Jul 17, 2022 3:56 am

Hi Mick & Laura,
I thought I might throw my 2 cents worth in; Firstly, don't let a small set back discourage you on the build, this is just one of the challenging hurdles of boat building.
I suggest giving the charred section of ply a good coat of epoxy and then re-glue and screw all the sections back together again ensuring everything is straight and true then (If you feel Ok with it) have a go at pouring the lead yourself, whilst it seems scary it isn't really that hard.
All the blogs remark how smoothly it goes and provide great advice. The trick to success is to ensure the sides are well supported and clamped with cement blocks or large pavers, also the base needs to be well supported and level. As Brent and Dmitiry suggested 3 or 4 separate pours. I used a small pot on a simple gas camping stove, and all went quite smoothly.
Good luck and let us know how you got on.
Cheers Terry

https://hookypocketship.blogspot.com
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Re: Lead Ballast Failure

Postby Mike&Laura on Sun Jul 17, 2022 6:06 pm

Thank you all for your suggestions and support. If I decide to go back to the lead foundry, I think I’ll build a mold to pour into rather than go strait into the keel. I did epoxy, fiberglass and even tried coating it with water glass to prevent burning. But I think all of you are right, they heat their lead to over 700 degrees. My understanding is that lead melts at just over 500.
Mike and Laura
Port Angeles, WA
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Re: Lead Ballast Failure

Postby jwv630 on Mon Jul 18, 2022 9:29 am

Hi Mike and Laura
Ugh; that's nasty; and sorry this happened to you.
Hang tough! For me as someone very novice, building Pocketship
has been very enjoyable mostly - with times of much frustration (understated!)

Take another crack at it. Good fellow builders in here with much experience and expertise.
Good luck

Jimmy V
'Miss Jen II'
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