Magnets and clay. Magnetic pottery?

Today I asked this question on Facebook in pottery heads and on the Curly Creatures Page, and it has been getting a fair amount of discussion in both spots:

“Has anyone ever tried firing a piece with a magnet *inside* it? I’m wondering if I could put a strong magnet (rare earth or ceramic) inside a void in a piece and seal it in (maybe with an air hole, maybe not.) Allowing some space around it should keep shrinkage rates from being an issue. I believe most/all magnets have a melt point below the cone 6 glazing temp, but wondering if it could be remagnetized (or would need to be) afterwards.

Thoughts?”

Since there’s so much interest, I thought I’d keep the general gist here for posterity. A list of thoughts:

  • It looks like clay firing temps are higher than a magnet can handle intact. There’s a table of curie temps here: http://en.wikipedia.org/wiki/Curie_temperature and the highest temp is only 1043F. Cone 6 can hit 2300F, but if you low-temp fire you might get away with it.
  • Changing to low fire process isn’t a great option for me, because the studio is set up for cone 07 bisque, cone 6 glaze. Would also require retesting clay bodies, new glazes, etc… for some, this could be an option that would allow using normal magnets and not having to magnetize.
  • Naturally, any magnets embedded should have enough space around them to allow shrinkage of the clay body.
  • Possibly magnetize after the fact with something like this: http://www.amazon.com/Wiha-40010-Magnetizer-or-Demagnetizer/dp/B00018AONE (although I’m guessing a powered tool would be better)
  • How about adding iron filings to the clay body and magnetizing it when the piece is finished? This clearly wouldn’t have the strength of a rare-earth magnet, but could work. (Can you remagnetize a rare-earth or ceramic magnet?) Also, attention would need to be paid to shrinkage – the clay body with all the ferrite would shrink less, probably glaze differently, etc…
  • Another possibility: after a first glaze firing, leave a hole large enough to accept ferric material filings – pour in, glaze fire again. This is an option, but would also really define the form of the final piece, since any holes for adding the metal would need to be able to face up during firing.
  • A sheet (or pieces) of metal that magnets will stick to could be embedded instead of a magnet. A few considerations:
    • This decreases the thickness of clay that can be between the pieces needing to stick together. Two magnets obviously have higher attraction at further distance than one and metal, and gauss goes as the square of distance. With fairly heavy pieces, this doesn’t give a lot of leeway.
    • If the metal melts below 2150F, in order to not break the piece it would need to either: not absorb/penetrate an open clay body, or expand/shrink at the same rate as the clay.
  • Raku firing: lower temp (1470F-1830F) that’s still beyond the Curie point of every magnet I’ve found so far, although on the lower end just barely past cobalt’s 1400F…
  • Add magnets after the fact, and disguise the spot. Considerations:
    • With no part of the structure over the magnets, the glue holding them in needs to be strong.
    • You can’t glaze over the spot (even cone 012 is 1623F – more than 200F over cobalt), so maybe a small glazed plug, and glossy epoxy. That’d be hard to get right, given warping of the plug and epoxy’s trickiness…
    • Epoxy or glue to level with the glazed clay around it, cleaned up so the seam is smooth, could get a layer of gold leaf and you wouldn’t know there was anything under it. However, I’m not sure how gold leaf would handle repeated impacts/abrasions from the opposite piece, so it would need to be protected more than usual. (Another layer of epoxy?)

I know I could just make the piece with voids and glue the magnets in, but I was hoping to hide the “how” for this work. So far I haven’t had a chance to try this, but I’ll come back with the results of any experiments, so Watch This Space.

Lamp-to-be

Sphere cut cleanly at 1/3 or so, hole punched through, black slip over (looks almost like carbon fiber.) cylinder w/top and bottom cut cleanly at 1/3, top rounded to sphere, divot to hold sphere w/hole punched through center. Black slip again. Once fired, acrylic or plate glass will go in the cuts, with lights run inside and glowing out through the transparent material.

Would have been nice to make the sphere fully solid, and use inductive power to run a led inside it, but I wasn’t sure what distance inductance could work over. Next time.

20131218-144514.jpg

A few more glazed

I can already tell that the little black cup is going to be one of my all-time favorites…

20131218-123103.jpg

More from yesterday’s epic session

How many hours at the studio yesterday? I lost track. Tons of good work through, despite a few pieces that needed to be redone on account of glaze going on too thick and peeling away as it dried. (Grr.)

20131216-075707.jpg

20131216-075720.jpg

20131216-075731.jpg

I finished by having some fun throwing geometric shapes. The cylinder and biggest sphere are going into a new lighting project. BTW: throwing a sphere is hard – it’s still not quite right, but prob as good as I can get it. Anyone have tips for this?

There’s some glazin to do heah!

20131215-125419.jpg

Tons of goodies came out of the bisque today!

A few goodies

20131211-155612.jpg

Last night’s quick studio session produced these three beauties. With luck, they’ll be out by Christmas! (It’s going to be tight.)

A lesson for webmasters…

A lesson that I shouldn’t have needed to learn: backup your site before doing any upgrades. I know better. It had been a while since I updated my WordPress install, so I clicked the button… done! Hmm – themes have updates too, no problem, I’ll do that…

It didn’t even occur to me that changing the theme would totally break my custom code – the new version of Atahaulpa disabled embedded php code. Suddenly, main page of the site = blank white nothing. Sometimes its good for the mind to be a blank slate, but not so much when that’s what the rest of the world sees.

So… working on fixing things here. In the meantime, the main page now directs to this blog instead of Finished Work.

Speaking of finished work, I’ve got all of my stoppers up on my Etsy page. A lot of work lately on functional stuff – some great bowls and new glazes I’m really happy with. One of my Creatures has gotten a gold-leaf upgrade (I’m struggling not to put gold leaf on everything now.) And I’m working up the best way to make custom handles for high-end espresso tampers… Fun stuff afoot! Right after I fix this site.

Long time no post…

Its been forever and I apologize. Life is super busy (as I like it), and I haven’t had as much time for creating as I’d like. However, I am working on something very cool – a chess set! Its mostly a project for me, but I’ll put it up for sale once its done to judge reactions… Very unique, taking a ton of time to make, but I’m loving how its going so far.

More on that soon, hopefully!

In the meantime, stay cool, and enjoy your summer!

Thoughts on branding

Ok – had a great discussion today with my neighbor who happens to spend a lot of time on marketing and ideas. Her thought: there are actually two types of stoppers, and they really should be separated:

Why? Well, the tall curls or spires are unadorned, simple, artistic. The creatures are more whimsical, fun. The creatures make you laugh, the spires make you say “ooh”. They definitely have different feels to them – it would be much easier to give a spiral to someone and know that they would like it, where the creatures have much more personality, which means they can appeal more to an individual, but also makes them more of an individual’s choice, rather than a gift.

So – thinking of names. For the creatures: Wineosaurs. Party Animals. Like them both, for different reasons. Wineosaurs is a fun thing, but totally skips the fact that they’re actually at least as well suited (if not moreso) to sitting on a bottle of scotch than a bottle of wine. (Scotch you open once and drink for a long time. Wine lasts a day or two usually.)

For the others… having a hard time with that so far, but would love thoughts. Something like “wisp”, except they’re more solid than that…

Busy season!

Stoppers are on the march, y’all.  Shelburne Vineyard has them for sale, home on Shelburne Rd will be selling them when they reopen (sounds like a cool place: wine tastings, local foods, local crafts, furniture – I’m curious to see how it works out.)  Block gallery in Winooski will be carrying them during their big yearly show in November.  There are a few other local spots I’m looking to get into as well.
Shelburne Vineyard display

All of which means: get making!  There are nine in the bisque kiln now, and I’m hoping to keep up at least half a dozen a week for the next month.
Waiting for firing

Its tough being in this stage – I believe in the product, retailers believe in the product, but I’m needing to make ahead something whose rate of sale is totally unknown.  One a day?  One a week?  A month?  Here’s hoping I don’t end up with too many in stock or too few to keep stores full!  Anyone have any tips on predicting this kind of thing?