BYYB Forums

(12-03-2009, 09:50 AM)mikestevenson link Wrote: [ -> ]. Am I wrong in assuming that nice planes would give a similar tactile pleasure?

Planing some straight grained pine with a well sharpened hand plane gives a sound, smell and feeling that is among the best I can think of.
In woodworking, I mean 

Here is my hide, the cache of lead


And here is the mould and the beginnings of the foundation where it is supposed to be embedded


This is the vessel I am going to use as crucible, with the tubing in the middle


As you can see, no snow but the ground is frozen.

I had to haul half a dozen wheel-barrow-loads of sand to have enough to surround the mould


And of course some of the sand found its way into the mould. It was a bitch to clean away because the mould was already leveled and fine tuned so I didn´t want to pick it up and turn upside down


But finally I was able to test how the tubing matches the mould


As you can see, there was not anymore enough light for the pictures without the flash. Working was still OK, though.

Another, split drum added as a hood to keep the heat in and all the lead loaded


I still need to make extensions to the handles of a sieve and a ladle toninght. Tomorrow morning I will pick up the torches from the rental shop, get another propane bottle and drive to the summer house to get started.

I made a small trial with just one piece of the cable shield and it looks like there is going to be one hell of a fire and smoke to be expected. The grease and tar still attached to the lead burned happily and made a lot of smoke. Let´s hope none of the neighbours gets scared and calls the fire department  ;D

I've done this a few times and a few notes: The most important as you know is moisture. You can't have any, not a single drop. Stand up wind, the stuff isn't anything you want to breath, it'll give your three headed babies if you're still of breeding age.

How well sealed is the mold? I ask because the ground under it will thaw quite quickly after the pour starts, so moisture can rear up and cause trouble if there's a leak. Please be careful, this stuff is hotter then a hooker, outside a Ford assembly plant on payday, in a mini van.

I will be wearing a persipirator when working near the pot. Most of the time I can hopefully just follow the progress from a distance  ;D

As for the babies, I have had mine already, five of them.

The mould is sealed to be waterproof, but of course some joint can crack. If that happens the steam will ruin the cast but that should be about it, I don´t expect the lead would start flying.

Here the pot is cooking  ;D Melting the lead went fast with no problems.


The big torches were plenty effective, one cooking underneath and I was using the other to burn the tar and other stuff.


The flames were not half as bad as was expecting.


A lot sooner than I expected I was skimming the crap from the surface of molten lead, preparing to cast it into the mould

After turning the pipe down there was no lead, but that was expected.


So I started torching the pipe and soon there was a couple of drops of lead but not more  :'(.  After a while several drops, actually a quarter of a cup, but that was water!  :o  Panic! Fortunately there was no lead following so I had time to dry it with the torch.
Probably some condensed water that was trapped in the pipe. 

Finally, after a very long time torching the pipes I got the lead running. The pot was so hot that I turned the torches off and just looked at the lead running and took some pictures. The mould was smoking but no flames and it looked like no leaks either. Everything looked perfect . . .


I should have stayed focused on the task instead of taking pictures. All of a sudden the the stream was weakening and before I had time to light the torches again it totally stopped. I was feverishly torching the pipes again, but then the torches started losing power.

I think the low temperature made the pressure fall in the bottles when they were not full anymore. With household appliances like a stove or a fridge this has not been a problem, because there is still more than enough pressure for them to work, but the big torches were losing their oomph totally. Shaking the bottles helped for a while, but joggling with the torches in my hands, shaking the bottles, even swapping to a smaller spare was really a challenge. I was trying to keep too many balls in the air and it was a losing battle. It took me a while, though, to admit that and the cast was cooling and stiffening fast.

Eventually I gave up and decided that I will ladle the last third of the lead into the mould to empty the pot. Obviously I would need to recast the whole thing. If I would have started ladling right away the first two thirds would have been hot enough to integrate the rest.

Here is the full mould, only very little was left to be scraped from the bottom of the barrel, maybe a third of a ten liter bucket. But it was a heavy third!




After some time I just had to check the casting so I dug it up from the sand. The mould was OK, no cracks and no leaks. That was good news for the next try.




After some more work the plain lead was there to be seen. Surprise, the seam between the two parts was not bad at all  :o


I need to check tomorrow, but it is possible that the casting is usable after all. As you can see, it was getting dark and I wasn´t able to investigate the results properly. At this time of the year it is too dark to work at 9AM and the same at 4PM again. And the summer house is the traditional finnish style, something the Americans would call a camp: no electricity, no plumbing. Just kerosene lights and candles. And an outhouse, of course.

But at the moment I feel optimistic, maybe I do have a ballast ;D
If that is the case, I am a boat owner, right? Once I have the first parts finished, it is a boat in the making. And because boats are measured by the weight, not by length, I have about one third of the boat finished   Not too bad at all.

I checked the results today. Not as good as it looked last night 

The top part was in thin layers that could be peeled easily apart by hammering them lightly. It might stay together when through-bolted, but the the surface was not good. And when I saw the smooth surface of my scrap cast in the bucket it was obvious that I want to recast in a steel plate mould. But that will probably happen after the snow, not before  ;D

That's a tough lesson to learn and I should have mentioned it. We call this "caking" and it happens when the flow of lead is too slow to fill the mold fast enough.

Picture the waves of molten lead gradually filling the mold as it dumps from the crucible. If the lead comes out fast enough, it's still molten when more covers the previous layer. If it's not fast enough, it cools just enough to form a thin crust, which doesn't bond well with more molten lead on top.

This is common in cold weather pours or if the lead is added to the mold too slowly. In an ideal pour, the lead is put in the mold as fast as possible without spilling or splashing it all over the place.

Try to position the crucible closer to the mold and use a much shorter and larger diameter pipe to deliver the lead. Pre-heating the mold and keeping torches on the molten lead while in the mold is asking a lot, but are both common tricks for cold weather pours.

You might be able to save the casting with 'glass cloth and epoxy. A couple of layers of 12 ounce biax to encase the ballast would likely contain it very well, but you do lose one of the benefits of lead, which is it's easily repaired if dented.

The caking on the top was unavoidable, because as I said, I was spooning up the lead after the pipe was clogged and that was hopelessly slow. I did it just to avoid the lead from stiffening in the barrel which would have resulted in a lot of problems afterwards. The bottom two thirds that was cast as originally planned was totally solid, no caking at all.

The problem was most probably caused by my misjudgement that the lead was too hot, burning the mould unnecessarily. Putting the torh away and picking up the camera was the wrong thing to do. ;D  But this was easier than I expected, no problem doing it again. The propane torches are a very effective and clean way to provide the heat. I wouldn´t consider using a wood fire after this experience, not even if we have free firewood from the property.

I will make a new mould of steel plate and recast the lead. It was no big deal to melt the lot and now that it is clean it will be even easier. My plan is to make the mould of thin plate and support it with plywood or something like that. Then I will lift the old casting as one piece into it and melt it on situ by torching the lead from top directly.