Mike Jordan
05-13-2008, 00:56
I have been doing a lot of searching for molds since I started playing with the Freeze and Fuse technique. While hopping around the internet one eveing looking for more molds that would make good candidates I ran across one that I had to jump right on. Although I did almost croak when I estimated how much the powder would cost to do this one. :D
So I ordered the mold and when it came in, picked up a couple of different types of green powder frit from Bulls Eye. I bought some Spring Green and Dark Forest Green. I already had the yellow and white that I was also going to use. After I finished packing the mold (more about that below) I put it in the freezer to firm up for about 75 minutes. I normally go an hour, but since this was so big, I decided to give it more time. That got it good and frozen and it slid out of the mold pretty easy. I did get a couple of small spots that stuck to the mold, but I didn’t think they would be too bad once fused.
Although the frozen part looks ok, I'm wasn’t sure how it would turn out. I did this one a bit different than the others and I didn’t know if I was breaking new ground or breaking the mold so to speak. My main concern was if it would hold together until fused.
This was also my biggest FnF so far. It took almost 3 pounds of green powder frit. I knew this one was going to take awhile to cook and anneal. I thought it would be about 40 hours but it wasn’t that long. The annealing was 6.5 hours itself though, plus the time going up and coming down. It's at times like these that I would really like to have a window in my kiln. :D
I almost always take pictures of the stuff I do and doing this was no exception. I took some just out of the freezer, which shows just how dull it looks in the frozen state.
http://www.sitnprettyphoto.com/display/glass/frog/frog8377.jpg
The frog is 8" tall from the top of it's head to the bottom of it's feet. It's widest area, the tip of the feet to the back end, is also about 8". The mold is about 1 3/8" deep at it's deepest but I didn't fill it totally to the top (it would have been over 3 pounds and increased the anneal time). From the frozen state, there will be about 20% to 35% shrinkage during firing. I treated this as being half way between 1.5" thick and 1.75" thick piece for annealing purposes because of the non-uniform thickness. I think I could have used 1.5" but I added a bit more to the annealing time just to be sure.
I said I did this one a bit different... What I did was not use wet frit to begin with. I started with dry. I put the Spring Green in several of the spots (I wish I'd put a few more but they were up on the vertical slop of the mold and wouldn't stay), a bit of white around the feet and mouth and eye. I did put wet yellow in the eye before I put white around it. After I got these colors in, I then sprinkled in enough Dark Forest Green to put a protective cover over it all. I then started adding the wet Dark Forest Green as done in a normal FnF mold. I went heavy with the water at first to allow it to soak down into the dry powder, hoping that that would do the same thing as it would had I put wet frit there to begin with and allow it to be packed down tight.
Another thing I did, since the body of the frog is so big, is after I'd put a good layer of green down, I then spooned in a bunch of dry white powder (I have a lot of white powder) into the middle from the head area to just away from the feet. This was probably 1/3 pound of white, but it let me save using all of my Forest Green. I then went back to putting wet Forest Green around it until it was encased and the white had soaked up enough of the water from the Forest Green to make it smooth out. I then put on more Dark Forest Green on top of this and took it up to within 1/4" of the top. I wasn't getting any bubbles from water soaking down and I had about 1/4" of water on top so I then started packing down with my packing tool. After it looked like everything was packing down ok, I bloated up some of that water and added another layer of wet green powder. Then I started packing and bloating and packing some more. I wanted to make sure that this was well packed together before I froze it. I finally quit getting standing water on top and it felt pretty solid when I held it. So into the freezer it went.
When I popped it out of the mold, I thought about trying to repair the couple of disturbed places and adding a bit more white around the mouth, but decided to leave well enough alone and go with what I had. I did get a chance to take a peek when it reached it’s top temp of 1320 before I went to bed and saw that it had held together, so I was relieved. After that I didn’t peek again till it was below 300.
Here is a picture of the mold:
http://www.sitnprettyphoto.com/display/glass/frog/frogmold8379.jpg
After the long wait for it to anneal and cool down, here is a picture of it fused:
http://www.sitnprettyphoto.com/display/glass/frog/frog8391.jpg
As you can see, the spots didn’t go down the back far enough. I wish I had tried getting a bit more Spring Green along the back. The white could have been put on a bit thicker as well. But it held together and showed me that large molds could be used with the freeze and fuse technique. It’s a lot easier than creating a plaster mold and either doing a open faced packed casting or a closed faced casting. And a lot faster as well. With a plaster mold around the glass, the fusing time and annealing would have been a lot longer, since the mold would have to be considered as part of the calculations.
I do have another mold that I really want to try, but I estimate it will need over 6 pounds of powder. Because it’s so big, I might try a combination of powder and larger size frit to save money. I have a lot of medium and coarse size frit from other projects and though I have tried a bit of fine grade frit, I’ve not used anything larger mixed with the powder when freezing it yet. It’s something to think about though.
Mike
So I ordered the mold and when it came in, picked up a couple of different types of green powder frit from Bulls Eye. I bought some Spring Green and Dark Forest Green. I already had the yellow and white that I was also going to use. After I finished packing the mold (more about that below) I put it in the freezer to firm up for about 75 minutes. I normally go an hour, but since this was so big, I decided to give it more time. That got it good and frozen and it slid out of the mold pretty easy. I did get a couple of small spots that stuck to the mold, but I didn’t think they would be too bad once fused.
Although the frozen part looks ok, I'm wasn’t sure how it would turn out. I did this one a bit different than the others and I didn’t know if I was breaking new ground or breaking the mold so to speak. My main concern was if it would hold together until fused.
This was also my biggest FnF so far. It took almost 3 pounds of green powder frit. I knew this one was going to take awhile to cook and anneal. I thought it would be about 40 hours but it wasn’t that long. The annealing was 6.5 hours itself though, plus the time going up and coming down. It's at times like these that I would really like to have a window in my kiln. :D
I almost always take pictures of the stuff I do and doing this was no exception. I took some just out of the freezer, which shows just how dull it looks in the frozen state.
http://www.sitnprettyphoto.com/display/glass/frog/frog8377.jpg
The frog is 8" tall from the top of it's head to the bottom of it's feet. It's widest area, the tip of the feet to the back end, is also about 8". The mold is about 1 3/8" deep at it's deepest but I didn't fill it totally to the top (it would have been over 3 pounds and increased the anneal time). From the frozen state, there will be about 20% to 35% shrinkage during firing. I treated this as being half way between 1.5" thick and 1.75" thick piece for annealing purposes because of the non-uniform thickness. I think I could have used 1.5" but I added a bit more to the annealing time just to be sure.
I said I did this one a bit different... What I did was not use wet frit to begin with. I started with dry. I put the Spring Green in several of the spots (I wish I'd put a few more but they were up on the vertical slop of the mold and wouldn't stay), a bit of white around the feet and mouth and eye. I did put wet yellow in the eye before I put white around it. After I got these colors in, I then sprinkled in enough Dark Forest Green to put a protective cover over it all. I then started adding the wet Dark Forest Green as done in a normal FnF mold. I went heavy with the water at first to allow it to soak down into the dry powder, hoping that that would do the same thing as it would had I put wet frit there to begin with and allow it to be packed down tight.
Another thing I did, since the body of the frog is so big, is after I'd put a good layer of green down, I then spooned in a bunch of dry white powder (I have a lot of white powder) into the middle from the head area to just away from the feet. This was probably 1/3 pound of white, but it let me save using all of my Forest Green. I then went back to putting wet Forest Green around it until it was encased and the white had soaked up enough of the water from the Forest Green to make it smooth out. I then put on more Dark Forest Green on top of this and took it up to within 1/4" of the top. I wasn't getting any bubbles from water soaking down and I had about 1/4" of water on top so I then started packing down with my packing tool. After it looked like everything was packing down ok, I bloated up some of that water and added another layer of wet green powder. Then I started packing and bloating and packing some more. I wanted to make sure that this was well packed together before I froze it. I finally quit getting standing water on top and it felt pretty solid when I held it. So into the freezer it went.
When I popped it out of the mold, I thought about trying to repair the couple of disturbed places and adding a bit more white around the mouth, but decided to leave well enough alone and go with what I had. I did get a chance to take a peek when it reached it’s top temp of 1320 before I went to bed and saw that it had held together, so I was relieved. After that I didn’t peek again till it was below 300.
Here is a picture of the mold:
http://www.sitnprettyphoto.com/display/glass/frog/frogmold8379.jpg
After the long wait for it to anneal and cool down, here is a picture of it fused:
http://www.sitnprettyphoto.com/display/glass/frog/frog8391.jpg
As you can see, the spots didn’t go down the back far enough. I wish I had tried getting a bit more Spring Green along the back. The white could have been put on a bit thicker as well. But it held together and showed me that large molds could be used with the freeze and fuse technique. It’s a lot easier than creating a plaster mold and either doing a open faced packed casting or a closed faced casting. And a lot faster as well. With a plaster mold around the glass, the fusing time and annealing would have been a lot longer, since the mold would have to be considered as part of the calculations.
I do have another mold that I really want to try, but I estimate it will need over 6 pounds of powder. Because it’s so big, I might try a combination of powder and larger size frit to save money. I have a lot of medium and coarse size frit from other projects and though I have tried a bit of fine grade frit, I’ve not used anything larger mixed with the powder when freezing it yet. It’s something to think about though.
Mike