Keel bolts - can we get serious now?

After digging deeper into the keel pocket it became more and more difficult to chisel out lamells in lead and melt them with MAPP burner. In desperation I even started drilling this damn lead but it ended up as expected - drills get clogged very quickly with easy-melting, sticky lead. In the end I broke the drill bit and almost seized my machine.

Something better was needed.
Something serious.

I’ve figured that even 2400 degrees C which MAPP gives is not quick enough to melt lead (which melts in ca 300 degrees) due to extremely quick heat dissipation. Two things can remedy this: even higher temperature and/or narrower welding nozzle - to heat the metal in smaller portions, quickly enough to melt it into drops before it solidifies again.

The highest temperature set available to me is acetylene welding set: welding gas + oxygen tank.

I’ve decided to give it a try. After all - I was desperate as my current approach stopped working.

So we got serious now: 3000 degrees C.

And it goes like cutting through butter!

A combination of high temperature and concentrated heat makes a trick.

The nice thing with acetylene welding kit is possibility to fine-tune flame composition to suit particular need. In my case I wanted concentrated but not very strong heat so adjusting oxygen flow gave me a torch which melts lead but does not cut it.
This same thing - adjustability - makes this set a little tricky in the beginning, when one learns how to adjust the flame. As seen on the film below - lightning the burner first time was a little troublesome but with few trials one gets a feeling for initial gases flow needed to succeed.

Unfortunately - oxygen tank lasted only 30 minutes. I need to get more supplies at hand. Anyhow - these 30 minutes made a work equal to 3 hours yesterday (and one MAPP gas tank!). So it was worth it. And no more chiseling in lead!

Meanwhile I ordered also smaller MAPP burner end-piece. I hope that it will work equally well - and I can have use for all this MAPP supply from my storage.

As for lead in the pocket - I intend to close these pockets again with lead but NOT pouring metal into the pocket. Instead I will use US-boatbuilders’ method: making lead pluggs which are hammered into the pocket, thus filling the space and making it watertight. The problem with poured lead is that one needs to accommodate metal shrinking on cooling (roughly 15% of volume) and also - future removal is again time- and money-consuming exercise. Having a plug hammered into pocket gives a possibility to drill and tap a hole in the middle, screwing in eyebolt and pulling the plug with hydraulic jacks.
Good discussion about ways of doing this is on WoodenBoatForum:
http://forum.woodenboat.com/showthread.php?158899-Lead-Ballast-Question/page2