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Bob Coyle

Member Since 06 Jun 2013
Offline Last Active Aug 26 2016 07:55 PM
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#109069 Bisque Fire With Paper

Posted by Bob Coyle on 20 June 2016 - 11:21 AM

If you use paper, it might be good to not use any with lots of colored inks. The pigments are mostly organic, but I think that some times there are metal compounds in the ink




#109030 Just An Other Newbie

Posted by Bob Coyle on 19 June 2016 - 03:58 PM

There are worse addictions... Remember, in throwing, once you get past centering... its all uphilll!




#108007 Building A Work Table

Posted by Bob Coyle on 02 June 2016 - 01:41 PM

I'll throw in with Neil, hardboard is a great surface for working with clay. Also I would recommend a separate wedging table with a thick plaster surface. Mine is 3 inches thick and 24x24 inches wide. I have 2 inches of concrete on the bottom and an inch of plaster on the top. I built it at just the height I need to be able to put my full weight downward into the wedge, rather than work only from the shoulders. Since the wedging table is separate, you can really slam the clay down  without shaking up everything else. I can also use it to roll slabs, using my trusty rolling pin.




#107274 Lose The Sitter Your Opinion Counts

Posted by Bob Coyle on 21 May 2016 - 08:11 PM

Leave the sitter. Digital controllers can fail, but gravity does not. Put a cone higher than you will reach in the sitter. It's there already, so why not have one more layer of fail safe.




#107236 Newbie Needs Help With Glaze Cone 6 - Can It Really Be This Hard?

Posted by Bob Coyle on 20 May 2016 - 06:11 PM

Cheat and throw in 0.5% cobalt carb.




#106547 Does Anyone Know How To Achieve Similar Results To This?

Posted by Bob Coyle on 08 May 2016 - 06:22 PM

It's simple... terra sig ... and ten years of practice.

 

Good luck Muddy




#103330 How To Increase Crackle Effect In Raku

Posted by Bob Coyle on 09 March 2016 - 07:28 PM

A lot has to do with the glaze and clay body. We are talking forced shrinkage here. I have found that thicker pieces sometimes crackle better than thin, but I have not a lot of experience in this.




#103001 New Blue Pigment

Posted by Bob Coyle on 02 March 2016 - 08:58 PM

“YInMn” blue... Humm ? Yttrium,Indium, manganese  here is the link to what they did http://colmat.icmse..../P27_DP2011.pdf

 

I agree with Niel, probably would be unstable in a melt. The pigment itself is created at 1100C, so you might be able to pull off a low fire, but it still would probably react with the flux and change color..  The glazes they made don't seem to be that impressive.




#100566 Stop Me Before I Ruin It Please

Posted by Bob Coyle on 24 January 2016 - 06:18 PM

Like Tyler says.... FIRE A TEST TILE! In fact fire many with different glaze/underglaze overlaps




#99827 Design Trends 2016

Posted by Bob Coyle on 15 January 2016 - 09:21 PM

Interesting Miss B... I have no doubt that the 3-D print fad will effect ceramics. It is no stretch at all from using molten plastic to thick slip to build a piece. Then the question arises... is it art or technology. In my mind it is technology, although you may use a graphics development environment to program what is made. I am pretty retro. I think that it doesn't count as art unless you are creating it directly with your hands. Of course , this would also rule out photography as a fine art media, and I have no problem with that.  I hope expressing my opinion doesn't get me flamed again, but this is ONLY my opinion.




#99529 Home Made Kiln Controller

Posted by Bob Coyle on 13 January 2016 - 05:50 PM

screen dumps of the user interface ...Attached File  chart.jpg   166.2KB   0 downloadsAttached File  ramp.jpg   93.28KB   0 downloads




#97982 My Journey In 2015 - A Big Thanks To This Community.

Posted by Bob Coyle on 25 December 2015 - 12:47 PM

Throwing like a pro Joseph. I like how you experiment with your forms. Looks like great fun.

 

Onward to 2016!




#97797 Glaze Test City

Posted by Bob Coyle on 22 December 2015 - 10:27 PM

Rate laws!... Gibs free energy!... I'm back in P-Chem!

 

Seriously though, trying to predict glaze behavior by more or less first principals is in my opinion, like using thermodynamics to predict the weather.  The complexity of more than a dozen different chemical entity's interacting in a molten solution would require some real hairy computation for even coming close to predicting anything.

 

This ground has already been plowed by geologists trying to understand rock formation and by scientists trying to develop better glass products.. both of which glazes are. I myself have downloaded many articles on these subjects and realize that the math of predicting behavior of even three or four component systems requires writing a complex computer program to crunch the permutations of possible chemical interactions that may take place.

 

I think Tyler summed up most of the research that has been done on multi-component glasses. the researchers found ....

 

The glaze itself is all a covalent lattice--ish (structure.)

 

Before anyone says a word more, I highly recommend they sit through this lecture on glass given at MIT. It is the clearest and best first principle-ish explanation I have run into... happy watching! :)    https://www.youtube....h?v=kB2Ue4Fip2c




#97136 Bismuth Nitrate Or Subnitrate

Posted by Bob Coyle on 10 December 2015 - 04:52 PM

Bi atomic weight is 209

that means the ratio of Bi to Bismuth Nitrate is 209/485  or about 43% by weight

 

and for Bismuth Subnitrate (209 x 5) /1462 or about 72% by weight

 

So the Bismuth Subnitrate is a better buy.




#95913 Horse Hair Firing

Posted by Bob Coyle on 16 November 2015 - 11:07 AM

Benzine is correct. Vitrified pots would probably crack, and even if they did not, the horse hair would not make the distinctive smokey trace. 

 

As I mentioned before, I have reheated bisque fired pots with a propane torch and then placed horse hair on the heated surface and it worked. You have to heat the surfaces slowly and bring them up to a high enough temperature to carbonize the hair. Hold the hair in both hands and loosely drape it over the hot surface.It takes some practice, but I have done lots of them this way.