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Bob Coyle

Member Since 06 Jun 2013
Offline Last Active May 25 2017 09:46 AM

#127167 What My Flutes Sound Like

Posted by Bob Coyle on 24 May 2017 - 12:33 PM

They would go well here in New Mexico.   Well done!

#124182 How Do You Make A Bird Bath?

Posted by Bob Coyle on 22 March 2017 - 07:43 PM

I'm not to worried about the squirrels... The neighbors bird bath was knocked over by a bear. 


Thanks for all the good advice. I'll have another go at it and try out some of the suggestions.

#123257 Small Rock Crusher

Posted by Bob Coyle on 05 March 2017 - 11:29 AM

The proximity of your hand to the belt drive in the vid,  looks like an accident waiting to happen. Maybe you should move over to the other side to dump the rocks in.

#122947 Glazing

Posted by Bob Coyle on 26 February 2017 - 07:38 PM

A very good start for dip and pour, but I do short glaze runs and only make enough to brush on... a whole new ball game. If I would give advice on brushing, the main thing I would say is keep the glaze thick, and try to "flow" it off the brush rather than painting it on like you would do a wall in the house. That way you do not have to do it twice, and You don't get streaks.


The key to a "flow" is to load up the brush and stop brushing when you feel it begin to starve out and pull against the clay. Load up again immediately and try to keep a "wet edge" (as the house painters say) against the last brush stroke. Thick glaze minimizes streaking since the glaze tend to level over the surface as it fluxes and becomes fluid.


PS ... dip and Pour are the way to go if you are doing production runs.

  • Min likes this

#119142 Silica In Glaze And Body To Ensure Good Fit?

Posted by Bob Coyle on 25 December 2016 - 12:05 PM

Not much more needed from what John and glaze nerd said... except YES!  you really need to pre test every change in clay or glaze before doing a full batch.  Fire at as close as you can come to the conditions you will fire the batch. Firing cycle can also make a big difference in the final appearance of a glaze. many of us here have learned the hard way that even going from batch to batch of a commercial clay or glaze can produce problems, and this is especially true if you mix your own glazes and change raw materials.

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#118978 Silica In Glaze And Body To Ensure Good Fit?

Posted by Bob Coyle on 22 December 2016 - 09:04 PM



No single component determines COE. it is a property of all of the bases present. If you know the COE of the clay body ( commercial bodies usually have this info) then all you have to do (theoretically) is match the COE of the glaze with the clay. There are many software programs that help you do that. From my experience they may not work as well as expected. They are good for a start, but they depend on a kind of a linear additive approach, which is not the way glaze works.  Adding or taking away SiO2 might get you to a better fit, but could alter the cone you need to fire to. The ramp you fire also effects  the final crystalline configuration of the glaze.  I have made glazes that calculated out with a close COE to the clay body, and well within major limits formulas and I still got some crazing.

#117634 Silicone Caulking Cure Time?

Posted by Bob Coyle on 01 December 2016 - 06:01 PM

It mostly loses solvent  in 24 hrs, but depending on the type, and how much air circulation it gets. it could take days to really cure out enough to not allow a bearing to slide off center.

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#115661 I Ate Some Clay.

Posted by Bob Coyle on 04 November 2016 - 02:18 PM

it wouldn't.... I tied throwing very fine silt and since it did not have the plate like structure of clay, it would not throw no matter how fine.

#114285 Wedging Clay

Posted by Bob Coyle on 04 October 2016 - 06:24 PM

Hi Sara78


Your best friend as a beginner... other than all the friends you will make here... is Google and YouTube. Just go and search on "wedging clay" and you will have access to how all the people of the world approaches wedging. I got  190,000 internet links to wedging and 5390 on line videos on how people do it.


Just Pick the one that works for you. There is no right or wrong way . ceramics has been around for millennia and every aspect is still evolving.


To begin with, just use the clay out of the bag. When you develop scrap that you will want to re-use then you MUST wedge it to get the air out.

#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