Crazing seems to always be somewhat of a debated topic among potters. I have always been a fan of it whether on functional work or not. Never one for safety it seems, I never really worried about it. Now that I'm selling my pots and people are (hopefully) using them on a regular basis, I need to focus on the safety of my wares.
The way I understand it, crazing is cracks in the glaze due to poor fit that can make the pot somewhat weaker and can also harbor bacteria in these small cracks. I have also been told that if your wares are not fully vitrified, they can allow moisture to absorb into the clay body and either get hot when microwaved or even break. They can even make otherwise safe glazes leech.
With that said, I use many pots daily (both pots made by me as well as other potters--some of them very well known) that have crazing and go through the dishwasher at least weekly and make their way into the microwave on a regular basis. I've never had any trouble and I never really worried about it. But then again, it's not me that I'm worried about. The way that I see it is that my pots are fully vitrified (I use cone 5 clay and bring it to almost a full cone 7--it slumps if too large of an unsupported span is made) and the crazing seems to largely be on the outside of pots where the two glazes overlap. The only exception to this is a few new bowls that I made where the overlapping glazes crazed some on the inside as well. The weird thing is that things have been crazing more than they used to--same clay, same glazes, same application. Here's one of the heaviest crazed pieces:
I know that a lot of woodfired and atmospheric fired work crazes, particularly shinos, and these pots are used regularly. I've even seen commercial wares with crazing that are said to be food safe and such--hell, some old plates we got for wedding gifts are crazed pretty severely.
So...what should I do? Should I try some new clay bodies with my existing glazes, or try to reformulate the glaze to get it to fit my clay body. Or, should I just not worry about it and keep on doin what I'm doin? I'm finally getting some really good glaze affects and I'm not super excited about changing things up, but I know that I should get it sorted out now rather than later. Any input is really appreciated. Thanks!!!