New To Kiln Firing And Need Help
Posted 27 July 2013 - 12:25 AM
Posted 27 July 2013 - 07:47 AM
Kiln wash is simple there are several recipes. 50 silica and 50 ball clay and if you want to dress it up add 5% alumina.
You probably wouldn't need that if you are firing low temperatures.
Make sure you have the proper wiring as described in the manual. Every else should be fine.What temperature is the slip you are firing?
Get cones for that temperature. You should have a little plate to set the kiln setter. It may be on the kiln setter possibly for stability during shipping. Nice hubby!
Marcia Selsor, Professor Emerita,
Montana State University-Billings
Marcia Selsor Studio in Brownsville, Texas.
Posted 27 July 2013 - 07:58 AM
As for the other older mystery kilns... Do you have any idea as to their names and model and model numbers? I think that knowing that might help the more knowledgable here help you with them. If they don't have a cone sitter or controller I would get some cones and place them where you can see them through the peep holes so you can see them and when they bend to the right degree you will know you have reached the correct temperature. There is also something called a pyrometer that you can get that you slip through the peep hole again to measure the temperature inside.
As for your previous disasters I know it's disappointing and makes going forward even scarier for you. With your first attempt it sounds like you started heating up the kiln and then put your pots inside, is this correct? If so they all blew up because you shocked them going from cold to hot too quickly. Think of bisque ware as frogs, if you place a frog in boiling what it will jump out but if you put it in cold water and slowly ramp up the heat it will sit there and boil to death because it does not realize it is getting hot. So next time put your pots in when the kiln is cold and then slowly ramp up the heat so they don't know they are getting hot. This will also give them time to burn off any remaining water they might have inside as well as burn out any impurities. Bisque ware needs to be done slowly especially until you learn what your clay can handle heat wise. For bisque you can prop open the top for awhile then close it. You can also leave the peep holes open until when you place a mirror in front of it it no longer steams up that lets you know all the remaining moisture has burned off and it's safe to close up the peep holes. My kiln is very small 18x23 inches and a bisque cycle takes around 15 hours to do including a 2 hour candling (its been very wet here and I am having humidity issues) so maybe you went too hot too fast the first time and then the second time maybe not long enough? It's really hard to tell since you don't know what temperature you went to. The popping and cracking after you removed them from the kiln is most likely dunting which is caused by thermal stress, you can look it up online and there are much better descriptions as to what causes this and how to prevent it.
I really think you would benefit from getting a couple basic books on ceramics they would fill in so many of the holes in your knowledge and I think make you more confident in what you are doing. I'm not sure if I helped at all but hopefully I haven't confused you even more! The real pros here I am sure will chime in with better answers.
Don't give up pottery is amazing and when you open your kiln for the first time and have fired a load successfully you will forget all about the trials and tribulations that got you there.
Posted 28 July 2013 - 12:15 AM
Posted 28 July 2013 - 08:14 AM
Kiln wash, I asked this question just a little while back and got lots of helpful answers. You can do a search for kiln wash here on the forum and I it should show up. A quick overview of what i was told and did is:
Mix your dry kiln wash with water to a chocolate milk consistency. Lay your shelves out face up. Use a large flat brush to brush on the wash. It will soak in very quickly and you have to kind of try different things to get it to go on as evenly as possible. Some people said they liked to use a roller so you might want to try different rollers or brushes to see which you like. I ended up using my biggest Japanese flat brush.
You do NOT put any on the sides or bottoms of your shelves and if you get any on those locations use a clean wet sponge to wipe it off before it dries completely since its easier to do so. On the inside floor of you kiln you can carefully brush on a coat of wash. Do NOT get any on your elements ( the metal wires in the walls and possible floor of you kiln) as this will make them burn out. I put a coat on the floor of my kiln and I also keep a whole shelf on 1/2 inch posts sitting in the bottom of my kiln. Doing this helps to protect the floor of your kiln. Do NOT put any wash on the walls or lid of your kiln.
Yes your shelves will have a powdery look to them and if you rub them the wash will come off, or at least mine do. I think this is normal so that if you have glaze get on them you can easily remove the glaze spots. Once you have run all the shelves through the kiln, this kind of seems to fix it on better, you can store them by placing them face to face. This protects the wash and keeps it from getting on the bottoms of the other shelves.
Good luck on finding out the mystery kilns name.
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Posted 28 July 2013 - 09:52 AM
hey, everybody else!!! look what asking a few questions last month did for pugaboo! aren't we all proud of what she has learned and is sharing. keep it up, terry.
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