We are loading the kiln- but take a break from the Pottery Blog and go enjoy some of our favorite recipes on our cooking blog. I love to cook and I love to use fresh ingredients and as local as possible. enjoy! http://yearsofcooking.blogspot.com/
Hello, I am catching up on some of my blog reading and see that you have recently been posting about specific gravity: There are lots of other ways to test glaze thickness most of these things rely on having had a positive result and then measuring that and being able to repeat it. The cuticle thing is simple and works for me - after mixing the glaze up, dipping a dry hand in and immediately looking at your cuticle and seeing a faint ridge. also I just watch how the slurry moves as I stir. Some people mix up the glaze, wash and dry their hands and then stick a dry thumb in - glaze sticks well to the skin but drips off the nail. Others stick their arm in as they are stirring and as they pull out the arm expect the glaze to cover the skin on the arm but are able to make out the hair... it's all very much by 'feel' but that's when measuring the specific gravity method is more scientific. There is also the method people in the paint industry measure paint thickness: there is a little plastic graduated cup you can buy ( I have one that came with my compresser and airsprayer - it's called a paint viscometer) that has a hole in the bottom of it and you count how long your glaze/paint takes to drain through the hole and start adding or subtracting water from there - keeping notes all along the way of course. Here's how to measure specific gravity, remember to use this once you find something that works well for your needs and then run these tests so that you have "a plan " for the next time you mix the glaze or when it dries out ect. -Mix up your glazes with water and sieve them. You will need something to put your liquid glaze in, I use a clear plastic cup that holds about 8 oz., put this on the scale and weigh it. fill it with 100ml of glaze and weigh it again. The difference in weights divided by 100 is the specific gravity . here's what was in my notes on my glazes - 100 ml of glaze that likes a thin application will weigh about 145 grams, or has s.p. of 1.45 A thicker glaze will weigh about 165 grams. You may want to start with a sample of your glaze and try to get about 165 grams, dip in a test bisque piece, then thin it out so 100 ml weighs 155 grams then thin it out again so it weighs 145 grams. So you'll have 3 tests to try in your firing and the one you like will be repeatable since you'll know what 100 ml should weigh.
Every now and then I make lots of test blanks and then keep them in a plastic bag so that I have bisqued clay pieces for my next flurry of testing.
Mary and I enjoyed our first fresh tomatoes from our garden for lunch yesterday. We made flatbread sandwiches with guacamole, basil leaves, parsley leaves, tomatoes and a squeeze of lime.
mmm, Michaels' sandwiches sound good too. while we were celebrating the new grill, our neighbor brought over a fresh green salad with the greens from her garden! the freshness combined with friendship were the perfect ingredients to our informal BBQ.
Sounds delicious! So great to be able to go out to your garden and harvest most of a dinner. You have green beans already? We are still in the middle of the June Gloom and my vegetable plants are just dying for some sun.
Thanks Ladyofclay for the good information. And Michael you have ripe tomatoes already!!!! I have bread what time should I stop over? Cindy I know you have to be in love with your new grill- Lucky You! and what great timing. Barbara- yep green beans and squash and basil. The lettuce and spinach just finished up. I do love eating from the garden. It just does not get any better.
5 comments:
Hello, I am catching up on some of my blog reading and see that you have recently been posting about specific gravity:
There are lots of other ways to test glaze thickness most of these things rely on having had a positive result and then measuring that and being able to repeat it. The cuticle thing is simple and works for me - after mixing the glaze up, dipping a dry hand in and immediately looking at your cuticle and seeing a faint ridge. also I just watch how the slurry moves as I stir. Some people mix up the glaze, wash and dry their hands and then stick a dry thumb in - glaze sticks well to the skin but drips off the nail. Others stick their arm in as they are stirring and as they pull out the arm expect the glaze to cover the skin on the arm but are able to make out the hair... it's all very much by 'feel' but that's when measuring the specific gravity method is more scientific. There is also the method people in the paint industry measure paint thickness: there is a little plastic graduated cup you can buy ( I have one that came with my compresser and airsprayer - it's called a paint viscometer) that has a hole in the bottom of it and you count how long your glaze/paint takes to drain through the hole and start adding or subtracting water from there - keeping notes all along the way of course.
Here's how to measure specific gravity, remember to use this once you find something that works well for your needs and then run these tests so that you have "a plan " for the next time you mix the glaze or when it dries out ect.
-Mix up your glazes with water and sieve them. You will need something to put your liquid glaze in, I use a clear plastic cup that holds about 8 oz., put this on the scale and weigh it. fill it with 100ml of glaze and weigh it again. The difference in weights divided by 100 is the specific gravity .
here's what was in my notes on my glazes
- 100 ml of glaze that likes a thin application will weigh about 145 grams, or has s.p. of 1.45
A thicker glaze will weigh about 165 grams. You may want to start with a sample
of your glaze and try to get about 165 grams, dip in a test bisque piece, then thin it out so 100
ml weighs 155 grams then thin it out again so it weighs 145 grams.
So you'll have 3 tests to try in your firing and the one you like
will be repeatable since you'll know what 100 ml should weigh.
Every now and then I make lots of test blanks and then keep them in a plastic bag so that I have bisqued clay pieces for my next flurry of testing.
Happy Glazing - Colleen
Mary and I enjoyed our first fresh tomatoes from our garden for lunch yesterday. We made flatbread sandwiches with guacamole, basil leaves, parsley leaves, tomatoes and a squeeze of lime.
Michael
mmm, Michaels' sandwiches sound good too.
while we were celebrating the new grill, our neighbor brought over a fresh green salad with the greens from her garden! the freshness combined with friendship were the perfect ingredients to our informal BBQ.
Sounds delicious! So great to be able to go out to your garden and harvest most of a dinner. You have green beans already? We are still in the middle of the June Gloom and my vegetable plants are just dying for some sun.
Thanks Ladyofclay for the good information.
And Michael you have ripe tomatoes already!!!! I have bread what time should I stop over?
Cindy I know you have to be in love with your new grill- Lucky You! and what great timing.
Barbara- yep green beans and squash and basil. The lettuce and spinach just finished up.
I do love eating from the garden. It just does not get any better.
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