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Member Since 28 Jan 2013
Offline Last Active Today, 10:50 AM

Topics I've Started

Air Release Mold Dies

29 July 2014 - 04:04 PM

I could really use some input. We have an air release mold system that I am adding a few dies too. The instructions are pretty straight forward but I am having a hard time with a couple of decisions on sourcing two of the materials.


1) The rubber for the models.


We are making the models in clay and then making master molds from them to be able to cast a new set of masters in rubber so that we can use these new masters over the years to remake the working dies.


The instructions I have to do this just call for a rubber urethane. There are tons of choices but I can find none that are specifically for mold masters. I was thinking of using Sharkthane Flex Pro 70-20  (2qt A/B 1-1 mix $35) that In spite of its name, sets hard. There are dozens of options and price ranges. I was hoping someone might have input on a good rubber for this purpose. Most seem to be flexible which for the mold itself would be great but for a master model I thought it should set hard. Is this a reasonable assumption?


2) The plaster for the working air release dies.


The instructions call for Ceramical but when I went to buy it my local supplier assured me that Hydrocal was fine since he didn't have Ceramical. Since this happened last summer (I know, I know) I need to toss the Hydrocal I bought then and buy fresh so I was researching the issue to make sure. I did find this link:




and they are clearly not the same but I was hoping someone could chime in if they have used such a substitution. My local supplier has a bag of Hydrocal for $25 but the only source I can find Ceramical is on the other coast and it is going to cost $60 to ship me a $30 bag of the stuff. i'll spend the hundred if I need to but obviously would like to have a local $25 source. 






How Long Should A New Batch Of Glaze Sit Before Sieve And Use

13 December 2013 - 02:09 PM

When I started mixing glazes I always made it a habit to mix the water in then let it sit overnight before re-mixing and then filtering before using.


Its been a number of years now and I'm not sure where I got this piece of advice but it is getting in the way sometimes. How long do you let a glaze sit before filtering it and using?



Multiple Test Batches On Same Base

06 December 2013 - 12:29 PM

OK I keep backing off and doing it the hard way because I am paranoid about skewing my results. The hard way is mixing each individual color in 400g batches one at a time even though I am working on the same base. I'm pretty sure this is silly and its making it very tedious to do 10-12 test batches at a time.


Tonight I am going to make one large 10000g batch of a semi-matt base I'm trying and then split it into 20 or so test batches and add oxides.


Is this how most of you do it?


Should I mix the dry ingredients and split out or should I add water and filter it first and then add the oxides to the mixed base?


I expect that I will end up making dozens of test with this base trying different percent's of oxides and other possible adjustments so this would speed up my work considerably.

Studio Glazes And Commercial Glazes

14 November 2013 - 12:13 PM

I would like to know if many professional shops that mix a house line-up of glazes also purchase commercial glazes as well. Is this a common thing or do most shops go one way or the other?  If you do augment your glazes with commercial ones, are you happy with that decision or do you feel trapped by it now? 


Any explanations of why and how you approach this would be really appreciated.