Making a Sundial - #1

[Paddy]

Dear All,

I made a version 1 Sundial. Based on blackmsiths journal #164 plan as a guide to rough dimensions, I then found some pictures on the internet of 2 master blacksmiths making a sundial at a blacksmiths get together. (Aspery & Legge, 2001)

Anyway, armed with some know-how and a few pictures I made version 1 of a sundial just to get an idea of what the process is about.

I made a 2/3 circle form from some 21 1/2" of 2" by 3/8 bent over the horn, welded a piece of angle iron to fix into leg vise. Ideally a piece of 12 or 15" steel pipe would be a better form, couldn't find any. Round was about 5 1/2" radius. I wanted to use brass but couldn't find any around, the steel bar would have been better maybe, but I had some 3/8" copper bar and thought it would look pretty. Punched the 14 spaces and 6am to 6pm, with a little to spare (1/2' each end). I know copper and iron don't mix, so I painted the item with hammerite and put a brass washer inside the holders. It'll do for a bit (maybe?). My weather vane isn't reacting and thats been there nearly 3 years.

Forged out the arms first, then the body, next time i will cut out the edges a little, the forging on my own was serious. I don't own a hammer drill so it was either a lump of wood or this pumice stone to put it in. Welded on a few spikes and drilled holes with a piece of 1/4" round hammered at the end to a chisel. stuc some steadying pieces on it.

Setup. Gnomon and 12 o'clock, point to true north (magentic depreciation) is 4.4 degrees out here (minus), and a 23 degree angle from vertical.

It was spot on. I adjusted the position slightly to my watch and the sun. Overall, I need a greater degree of accuracy and finish. I'm waiting for some Jax blackening fluid to improve the finish maybe. Hammerite black is not ideal.

Has anybody else made one or has tips or ideas for better design?.

I found that they can get plenty technical, few actual examples of simple forgeable examples, except cast versions and a few super level blacksmith ones out there that are way beyond my ingenewity. I thought just go and make one and see if it works to understand the principles. It broke the ice on what I thought would be somewhat complicated instrument.

My technical brother in law said how hard is it?, just put a stick in the ground?. Can't see how that will make a garden feature somehow....



Thanks,

Paddy

[pkrankow]

OK, you have the opposite problem of most people. You need to post BIGGER pictures! say 400x? pixels. The thumbnails are bigger than the full size image!

Copper and iron is done frequently, but there are understandable reasons to try and isolate the metals for outside use. The whole galvanic corrosion issue, which can be used to your advantage by fastening a chunk of aluminum or zinc in a hidden portion. Modern clear coatings help too.

I'd comment on the work, but after enlarging ( [ctrl] [+] ) there is no detail.

Phil

[Wesley Chambers]

The whole galvanic corrosion issue, which can be used to your advantage by fastening a chunk of aluminum or zinc in a hidden portion.

Phil

I understand the basics of how this works, the corrosion is drawn to the zinc or aluminum but I thought they needed to be submerged? Teach me Phil, teach me!

[John B]

Here are some very simple examples made some years ago on a one day course we ran,


And this one in a 2 hour long live competition.

They don't get much simpler except for the stake in the ground

If you want fun, wait 'til you get to the wall mounted vertical face ones.

[pkrankow]

I understand the basics of how this works, the corrosion is drawn to the zinc or aluminum but I thought they needed to be submerged? Teach me Phil, teach me!

Not submerged, but wet with the same electrolyte. This only matters in the rain for most work, as high humidity is not normally enough, although in some cases dew or light condensing humidity is all it takes. Look up galvanic corrosion, the wiki entry has a good bit on this problem specifically with the Statue of Liberty.

http://en.wikipedia.org/wiki/Galvanic_corrosion

Phil

[Paddy]

Cheers Guys,

Hello Wes!.

thanks Phil for the photo advice. I think I'm takign 5mb photos and I put them to a large email resize and it was 33-38kb, bit too big, so went to the small email instead. I will use 3mb setting on camera next time and hopefully get bigger small photos.

Really good info on the use of ali or zinc. Got some of that. I can easily make something there.

John B = great stuff. I'm going to make a better one next week and will take some more photos. Without a rock also. Like the base design, simple and neat.

That rock was shameless expense on my part - $15 for a pumice rock!.

thanks,

paddy