Raw Glaze Materials Suppliers/Materials analysis

[DBPottery]

I'm now starting to get into making my own Cone 6 glazes. I've had enough issues with commercial glazes sold for cone 5/6, and even more so now that I've been convinced I need to fire my clay to Cone 6 (originally I was told to do cone 5, but for vitrification purposes, Cone 6 is needed). 

I'm based in Tampa, FL. Ideally trying to get my raw materials locally vs. shipped in. I see plenty of places to buy the raw materials. I just seem to be hitting some road blocks when requesting a materials analysis. 

I've been using Hessberth's and Roy's Mastering Cone 6 Glazes and John Britt's Mid-Range Glazes book for guidance. Additionally, I'm using the Glaze Master software to help make some conversions for materials now unavailable.  Based on these, I've been convinced a good materials analysis is necessary. 

How much is it worth fussing over a good materials analysis? For example, one supplier lists a "typical analysis" on their website and Glaze Master has some pre-populated. I get the feeling I might have received some old analysis docs from one supplier, rather than the current lot #. 

Most of the analysis docs I've received, are close to what is already in Glaze Master (with 1% or less), so I'm thinking I might be fussing over it a little too much, but need some opinions. 

Any recommend suppliers?

Thanks in advance.

[glazenerd]

DB

www. ronroy.net. Ron has several analysis pages that he keeps up to date. In the USA, the Feds only require the original analysis when the MSDS sheet was released. Some clays, spars, silica, etc are decades old. Using higher purity grades of spars, silica, and clays do help to ensure more consistent results. Glazemaster does allow you to update individual material analysis for materials. 

Axner Supply is somewhere down in Florida. Well stocked, large inventory. Individual analysis would be costly and  would still not produce consistency. Old Hickory Clay updates every 2 years, Christy minerals just upgrades their fire clays last year. Sent these to Tony at the end of last year, do not think he has had time to look them over.

T

[neilestrick]

Any glaze formula is just a starting point, regardless of the accuracy of the materials analysis. There are so many other variables in the process that the materials accuracy will only get you so far. I always use the stock analyses in my glaze software, and it doesn't slow me down any.

[DBPottery]

Thanks for the replies. I feel much more confident moving forward now. Hoping for the best, but I know a lot of testing is to be had.