Author Topic: Hollow Balls (Read 1103 times)

Powder keg · « **on:** June 04, 2006, 04:27:05 AM »

Hey, This was brought to my attention a couple of days ago and the guy wondered if I thought they were safe. Here is a link http://www.jt-bullet-moulds.co.uk/moulds.htmand a picture.

I might be afraid that they would become unglued in the barrel? I wonder what type of glue he is using? Can you solder lead or Zinc? These wouldnt be much harder to build than the round molds. What are your opinions?

Thanks,

Double D · « **Reply #1 on:** June 04, 2006, 04:45:08 AM »

Must be a better way. I would think those have to much chance of coming apart in and out of the bore.

How did they make the real deal?

Powder keg · « **Reply #2 on:** June 04, 2006, 05:38:45 AM »

The origonals were sand cast. They had a sand core that filled the space on the inside. After the ball cooled the sand was removed through a hole left by the core. I think they would be time consoming to make. I'll see if I can find a picture.

GGaskill · « **Reply #3 on:** June 04, 2006, 09:16:03 AM »

It should be easy to solder lead, especially with 60-40 solder which melts at a much lower temperature than pure lead; zinc is solderable with appropriate solders and fluxes. Probably the best way would be to solder in an oven where temperature can be well controlled and many pieces done at once. Only special requirements there is the use of a paste solder as you won't be able to hand feed it.

In the case of zinc, you should also be able to weld the pieces together if you can control the application of heat.

Powder keg · « **Reply #4 on:** June 04, 2006, 11:18:55 AM »

So if they are soldered then they should be safe then, Right?

GGaskill · « **Reply #5 on:** June 04, 2006, 01:19:55 PM »

Well, in the case of lead ones, the joint should be stronger than the base metal.

And with the zinc, if they were TIG welded, that would be as strong as the base metal.

Double D · « **Reply #6 on:** June 04, 2006, 05:43:17 PM »

Sure seems like it would be whole lot less work to cast them hollow to start with.

GGaskill · « **Reply #7 on:** June 04, 2006, 10:44:40 PM »

Here's a cross-section of a ten inch shell (dia=9.85", wall=1.6", fuze hole tapers from 1.75" to 1.51".)

And remember, whatever causes the void in the middle has to come out through the fuze hole.

guardsgunner · « **Reply #8 on:** June 05, 2006, 01:52:41 AM »

Try making a mold for a core of casting sand, freeze it (CO2 fire ext.)
I think thats how my 24pdrs were done.

Cat Whisperer · « **Reply #9 on:** June 05, 2006, 04:29:23 AM »

Are not cores typically moulded and then baked prior to use?

guardsgunner · « **Reply #10 on:** June 05, 2006, 05:10:45 AM »

I dont know.

If you baked casting sand would in not form a hard clay sand mix which would be hard to remove.

No experince or real first hand knowledge here.

Cat Whisperer · « **Reply #11 on:** June 05, 2006, 11:57:54 AM »

After casting, the cores are broken out. They crumble relatively easily.

Perhaps a bit more work when the casting is a sphere all the way around it though.

Artilleryman · « **Reply #12 on:** June 05, 2006, 12:30:24 PM »

You don't have to remove the sand core. Leaving it in would approximate the weight of the bursting charge. The use of C02 in making sand cores requires the use of a chemical that is mixed with the sand (don't remember the name of the chemical), and the C02 acts as a catalyst to make the sand core hard. This is core is made around a piece of conduit that has holes in it to let the gases from the sand escape. You put some steel wool inside the conduit to keep the sand out.

5toolman6 · « **Reply #13 on:** June 05, 2006, 12:58:52 PM »

Quote from: guardsgunner

Try making a mold for a core of casting sand, freeze it (CO2 fire ext.)
I think thats how my 24pdrs were done.

Your core was either made with Sodium Silicate or more likely with Ecolotec and was cured (set-up) with Carbon Dioxide gas.

GGaskill · « **Reply #14 on:** June 05, 2006, 01:19:27 PM »

If you decided to leave the core in the casting, it could be held on a wire in the mould with no fuze hole needed. Then just cut off the excess wire after casting.

Double D · « **Reply #15 on:** June 05, 2006, 03:56:40 PM »

I knew you guys would figure it out!!!

Terry C. · « **Reply #16 on:** June 08, 2006, 12:29:56 AM »

I've never tried this with lead or zinc, but I got to thinking about friction-welding the halves together.

What I envisioned is pair of fixtures, one for the lathe chuck and one for the tailstock. These fixtures would hold the ball halves in position to be spun against each other.

I'm thinking it would not take a lot of speed or pressure to fuse soft metals like lead and zinc sufficiently to stay together during firing.

Like I said, it may not work, it was just an idea.