Making a Pz III/IV Cupola

[Hoffner]

Damn, I would love to have one of those printers.

[Hammer's Africaners]

Wow that's awesome

[Eddie Acosta]

Awesome job. Great pics and info. Thanks.

[Jim Fowler]

Hi everyone,

I would like to take a moment and say that Brian's work IS FANTASTIC! I purchased a set of Panzer III swingarms from him; and trust me, they are EXCEPTIONAL!

The swingarms are cast in aluminum, so he does know the venue. They are correct in their rendering and more than strong enough to carry the ArmorTek Panzer III they were created for.

I have an interest in the cupola he is making as well....for my Panzer III and Panzer IV.

He is a great guy and I for one can not thank him enough for taking on this effort; and sharing it withr myself and others.

Best Wishes,

Jim

[Brian Leach]

Thanks Jim!

Hello everyone!
Yesterday I finally got a test pour in. It went well though not as planned (does it ever?).
My furnace had trouble coming up to the temp needed for brass, so I poured aluminum instead.
I had had a long day of it with the problems with the furnace, so I didn't bother to degass or flux the aluminum. This led to impurities getting into the casting, and having a porious surface. I also poured the aluminum too hot which contributed to the porosity. That being said, I think the casting went well. Now I need to "tune-up" my patterns and do a large pour and begin making the cupolas.

I would also like to note that this cupola was also used on the Pz IV, and yes with a bit of work I will sell these, but that is for another post...

This is the setup. The paint pots are used as a large vacuum resivoir for the vacuum chamber


This is the flask ready for investment and vacuum degassing

Bottom of flask with investment

Top of same


Flask in oven. This goes through a series of temperatures up to 1150F. It took about 16 hours to "cook". in this picture the flask is upside down to let the wax run out as it melts. I recover that in water under the flast. After two hours of this I removed the pan, inverted the flask and started some serious burn out starting at 750F...

The furnace

Crucible with melted aluminum. Note: this was too hot (indicated by color)

Flask after pour

Flask after being immersed in cold water. The investment instantly shatters allowing easy removal from the flask

And here are the castings. As noted earlier, they are not perfect. This was kind of a "proof of comcept" run



I hope you enjoyed. If you have questions I'll try and to answer them
Have a good day!

[pzrwest]

I remember watching "How It's Made" and remember them stateing when they cast aluminum blocks the aluminum was poured into the mold from the bottom to prevent oxide etc from affecting the aluminum

[Jim Fowler]

Wow Brian, when you say the aluminum was too hot and could tell by the color (I assume the violet shade)...What would be the correct color?

Jim

[Tigertiki]

Hi, very nice job ! I thought that the "investment" is some sort of sand but as i see is rather like plaster. If it is plaster than serious problem is degassing. Can you give some info about it ?
Thanks

Attila

[Brian Leach]

Hi

Jim, the color of the aluminum would be pretty much mercury colored. To be clearer, the crucible holding the molten aluminum should be a duller red, maybe not glowing near the top.

The sands I use for other castings I make, like the Tiger I towing pintal or "C"-hook, are called green sand and k-bond. The K-bond is a sand bonded togather by oils in the sand. The green sand is bonded togather by clays in the sand. Most castings cast in sand are made in split boxes and you can often see the join lines. With the investment, or lost wax, casting you get every detail in the wax, but it is a longer process. I can do sand casting in an hour or so, investment casting: three days.

I hope this helps some,

Oh, and by the way Jim. I think I will remake those swing arms for you by the lost wax method rather than just making those back plates.

Have a good day,

Brian

[Eddie Acosta]

Awesome casting work.