clear glaze developes milky spots in place???

Zander,

I see what you mean.

My immediate reaction is a tad under-fired

Are you firing with cones or just a controller?

Either way I suggest a 30 minute soak at the end, or if you can't do that the next cone up.

I know it supposed to be cone 6, but, like the man said, this can be a problem with off the shelf glazes. In the end you are far better off making your own glazes if you can; you can adjust them to suit your kiln and way of firing because you KNOW what's in 'em. With bought glazes the ingredients are often a mystery and you are groping around in the dark!

Steve Bath UK

In article , Zander writes

Steve,

newbie question: If I soak the kiln for 30 minutes will that move the cones beyond cone6 or will they stop moving at the peak temperature? I do normally soak the kiln but only for 5 or 10 minutes until I see a cone6 at about 3 o'clock or so.

I'm a new controller owner (bartlett v6-cf) so I'm still adjusting to that but it's already a huge help in shelf to shelf consistency.

The shelf those clear pots were fired on showed a cone6 slightly overfired (about 100degree on the orton scale, just past the top of the plaque).

Do you think refiring those clear pots could help?

Thanks,

Zander

Steve Mills wrote in news: snipped-for-privacy@mudslinger.demon.co.uk:

Steves answer could be right, otherwise, haven't seen anything like it myself. The commercial clear glaze I use can turn slightly milky over dark clay if thick, but not nearly as noticably as this, and it is when it is really thick. Firing to reach cone 6 in my electric kiln I set to 1200C and soak for 30 minutes For what its worth I don't think it ruins the pots at all, they look good.

"annemarie" wrote in news:VTAjd.376$ snipped-for-privacy@news02.tsnz.net:

Thanks Annemarie, I think maybe I'm not soaking long enough based on yours and Steve's comments as well as tips read elsewhere. I fire with a controller but base my program end temp on when a regular cone6 is just touching the top of the plaque it's in. I have been holding for about 5-

10 minutes normally, I guess I'm worried if I up this to 30 min I'll just be overfiring?

I'm confused about the effect of soaking on cones... I have to remember that most of the ware is coming out fine. But this milky spot problem has ruined about 10 large bowls in the last while, it's getting very frustrating. I think I'm going to dump that glaze or save it for experiments only.

Thanks,

Zander

OK,

Cones measure accumulated heatwork, controllers/pyrometers measure the temperature prevailing at the exact moment you look at the readout, so cones behave like clays and glazes. A long slow firing will achieve the right amount of heatwork at a lower INDICATED temperature. It's exactly the same as using a slow cooker. You are doing absolutely the right thing checking your Controller against the cone. So following on from above; yes the cone will soften more. I fire my cones until the tip touches the kiln shelf it is stood on. By all means re-fire your work, and in the future glaze a little thinner, and fire a little higher, or as I suggested a good soak. I like to think of glaze firing as like putting on an overcoat; if you rush out of the door putting the coat on as you do it takes about 25 yards or more to get it comfortable, and even then it not really right. Better to put the coat on slowly and carefully and THEN walk out of the door in a relaxed fashion.

:-)

Steve Bath UK

In article , Zander writes

Just to add - the blistering is another issue that might be dealt with by doing a soak at the right temperature. Two sites that I recommend

I think your pieces are quite lovely with or without the milky spots. With the style I can see why you might want it not to happen but then there are those who will like it because they do make each piece more unique...

Thanks Dkat,

I've already ordered the mastering... book! So I will wait for that to come, We (my wife and I) are still very inexperienced with glazes/firing etc.) so hopefully with all the great advice we've received and a little more experience we will start having more success.

BTW, do you have any idea where to go to buy bulk sieve mesh? I want to build my own but have struck out finding the mesh.

Thanks,

Zander

of places on the net but I have not bought any so could not recommend anyone. I recently read a really cute way of making a strainer though - Take a 5Gallon bucket and cut off a ring from the top of a few inches. Then take the bottom that is left and drop it through the ring (think of the wider part of each as being the top side). Where it catches mark the top and bottom and cut off this second ring. Now put your screen on the inner ring so that it is on the outside of the ring and covering the bottom (think sock on a foot). Drop this screened ring into the outer ring and force it down tight.

In article , W_D_Great_Divider writes

OR:

get an off-cut of plastic drainpipe or a heavy duty plastic bucket with its bottom cut off, heat up a hot-plate to about 300F put a piece of cooking foil shiny side up on it, your mesh on that, and press the piece of pipe or bucket onto that until you see it melting around the edges. lift it off, put it on a cold surface for a few moments then peel off the foil. Viola!

Steve Bath UK

I got mine from McMaster-Carr. They are a huge industrial supply operation but they sell to individuals and have great prices. I got "type 304 stainless steel woven wire cloth" in 1ftx1ft squares for about $7.50 each last year. Here are the part numbers to look for on their site. (Forgot their URL, but Google on McMaster-Carr to find it): 20 mesh 85385T851 40 mesh 85385T864 60 mesh 85385T866 80 mesh 85385T869 100 mesh 85835T872

Total for all 4 pieces was $34.59 plus 4.25 shipping... and delivery was in only 2 days! They also have larger sizes as well.

Best regards,

Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis

I have this happen all the time with commercially made clear glazes...and I have tried three or four. I'm not quite ready yet to make my own glazes...but I found, by doing test tiles that I can sometimes get the clear glossy sheen I am looking for by using only 1 0r 2 coats. Try some test tiles for yourself and see!