working orrery magazine

Just picked up the first part of this magazine (in UK ) for building a working orrery. Don't get me wrong, I have no intention of buying any more of the 52 issues at £6-99 each, but the first issue is 99p and apart from some interesting background on orreries you get a nice chunk of brass plated steel 11cm in diameter and about 5mm thick with the zodiac signs engraved on it, along with a thin ring which fits around the outside of the main disc.

If you are looking for a chunk of steel around this size it is probably worth it for 99p.

Doug

It seems that a few people have made this and are quite pleased with it. the price is not hugely more than buying the same Orrery ready made from the original manufacturer.

Does seem to be a decent quality item, rather than a bit of tat, although those of us here will build our own

Neil

52 Issues at one a month sees you still making this in 3 to 4 years time! Also nearly £350 down. Maybe get the plans and make one?

Clive

My first contact with an orrery was in 1971 when I visited my uncle Lyle in Utah. He had to show me the sights and we had a great time. We happened to be at Dead Horse Point Utah where the parking lot fronts almost on the view-point - a marvelous vista of the North end of Grand Canyon where cubic miles of empty air below our feet emphasized the immense scale of the works of nature.

The Park Service was developing a tourist attraction nearby and among the new features was a planetarium, a lecture hall, and among the exhibits there was to be a beautiful orrery the rangers could use to illustrate their evening lectures on the mysteries of planetary motion. The orrery was built by a specialist sculptor. It was a grand glittering piece of brass and porcelain enamel and fine mechanism eleven feet across which arrived in time for our visit.

I was drawn to it like a moth to a flame. Naturally we had to rubberneck.

Apparently its creator was a far better sculptor than driver. He'd un-tarped and un-lashed the magnificent piece and was backing the trailer to get to the loading door when he jack-knifed it slightly. In slow motion the orrery tipped off the trailer, rolled on its wide round base like a huge pie tin across the parking lot, gained speed on the gentle slope, bounced over the curb, and went over the guard rail to roll into the gorge. There came a fine series of diminishing crashes as it fell from terrace to terrace to terrace for thousands of feet to scatter its glittering remains on the bank of the wide Colorado River, a mere ribbon of water far, far below.

A dozen people tried to stop it and a dozen people watched it go down the canyon. When it finally came to rest there was brass and fine mechanism scattered all the way down the slope; over a year's work was ruined and unrecoverable, sparkling wreckage amid a treeless desolation. We all looked at each other and at the weeping sculptor, a tragic figure if there ever was one.

People gathered at the guard rail. There was a grieving hush such that you could hear the roar of the river nearly a mile below. A small voice spoke. "That's a long way to tip orrery."

It's weekly!

> "That's a long way to tip orrery."

Noooooooo!

Neil

Edited By Neil Wyatt on 21/08/2015 15:23:54

As a matter of interest has anybody got a set of plans for making an orrery, it would make an interesting project.

Doug

If you google Orrery Gear Ratios you will find lots of postings by people trying to find them.

Might have a go myself...

Neil

and how do you do BRASS plating I thought only one metal would come out of solution when plating.

Edited By Neil Wyatt on 21/08/2015 19:56:16

.

I don't know the electrochemistry, but apparently it is done:

"The plating is most commonly a single metallic element, not an alloy. However, some alloys can be electrodeposited, notably brass and solder." [from Wikipedia, on electroplating]

MichaelG.

[surprised you didn't pick-up on this when I mentioned it on the other thread]

Edit: Here is a patent

Edited By Michael Gilligan on 21/08/2015 20:31:48

Edited By Michael Gilligan on 21/08/2015 20:44:30

Electro-brassing is very common in (or rather on) cheap hardware such as door bolts, hooks and rusty brass screws. 30 Years ago I started a new job as production planner in a door factory and my first task was to find a supplier for brass self-tapping screws! Fortunately I knew a local plater pretty well and was able to get some stainless screws to him the next morning. It took me three months of arguments with the design office to get the drawing corrected though.

Brian

If you are maiking this it is worth looking up the build logs from the last time round probably on that stargazer link posted earlier. I read along with it and recall there were some necessary adjustments and corrections along the way. One of our club members did build it and a couple were included on stands at Ally Pally.

The ME index shows a few entries to look up. Looks at piles on non ordered copies of ME - I may be gone a while.

Neil,

For info. ... Back in the old days [when men were men, etc.] the process was Hot Brassing

Commonly use on cheap screws, picture hooks, hinges, and such.

MichaelG.

Thanks Michael,

I looked at that page, but didn't see Brass listed, just various elements, and moved on.

My guess way very similar electronnegativities, but though Cu and Zinc are fairly close, lead is far from tin.

Neil

Edited By Neil Wyatt on 21/08/2015 22:15:02

This looks interesting (and affordable)

John- I can't help wondering if that was a wonderful story looking for an inspired punchline or a wonderful punchline looking for an inspired story.

Doug

Brass plating is a very well known and understood process.

Most decorative brass plating is applied over an under layer of nickel in a similar way to chromium which also relies on the brightening and levelling properties of bright nickel plating. There is a less well known engineering application; brass plated steel has a much greater adhesion than the bare metal when bonding rubber parts to it.

Different metals will indeed deposit out in a plating bath; brass, bronze, and tin / lead, tin /zinc, and zinc iron alloys are all are common enough, and there are dozens of gold alloys too which give different colours and wearing qualities. I was a development chemist when tungsten / cobalt alloys were being used as facings on forging dies. If a zinc based diecasting drops into a nickel bath it will dissolve in the acid conditions and start to plate out as a very much unwanted alloy, as will copper. Both bring about black streaky deposits; the experienced eye can tell which is present.

The normal brass bath is cyanide based, contains brass and zinc in solution, and utilises brass anodes. That keeps the alloy percentages pretty regular, and hence the colour doesn't vary too badly. We used to run on copper anodes (cheapskates!) and add extra zinc salts as we went along; this is a much more difficult process to control, and is unpleasant to run; fine tuning the colour requires an addition to the hot bath of liquid ammonia .... lovely.

Eug

Edited By Eugene Molloy on 22/08/2015 12:50:37

Thanks for the useful notes, Eugene

MichaelG.

Indeed, thanks Eug.

Neil

I dont see an "edit" function in MEW so I'll correct my typo in the final paragraph....... a normal brass plating bath contains copper and zinc in solution not brass and zinc.

I think the ammonia fumes were getting to me even after forty years!

Eug

I had a chemistry teacher who had an ammonia -sniffing habit

Neil

Just as you say Neil, weekly editions of the Orrery, today WHS had a cabinet by the door full of the things.

The package is quite heavy as well. I wonder how well it will sell?

Clive