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dipping glaze leaves large bubbles on ware


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I am glazing some pieces for a charity auction so time is of the essence so I am hoping someone can help me. I am using a mayco dry mixed glaze. Have used it

before without this problem. Cone 6. I am gently stirring my glaze before I dip or pour not agitating it. I am getting very large bubbles that are all over my

pots. These are not pin size that I can just rub down. Honkers! and lots of them. This is the second coat glaze. I've tried dipping slowly in and out, shorter dip time,

one to two seconds instead of three. I don't think any of the pieces had a long first dip (2-3 seconds). It is too late to get tech help from Mayco so maybe this happens

to others and someone can suggest a solution. I have already had to wash off glaze completely on several pieces because after I popped the bubbles It was a

mess. Let me know If you need any more info. I hope to glaze these this eve. Thanks!!!!! Yes, I am a newby.

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You said that you used the glaze before, did you do anything differently? Has the ware been bisqued to at least cone 04 and is it clean? Did you mix according to the exact manufacturer's directions? Did you wait for the dry particles to 'slake' in the water before glazing? Did you use clean water? Have you rinsed the bisqued ware in clean water prior to glazing? It could be possible that the batch has been misformulated.

If the glaze is reacting differently, the company should be notified.

Also you can try brushing on the glaze instead of dipping.

This glaze requires testing before you commit this glaze to important pieces.

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Thank you for your reply. This is a batch of glaze is a month old and I have used it 5 times, and it is 3/4 full. It is not a new batch I am comparing it with just the same bucket of glaze.

Bisqued between 05-04. I followed directions and this batch has not done this in previous dips. I wiped down the pots with a damp sponge cleaning it from dust. The first coat dried about 30 minutes

before the second coat was applied. I took it out of the kiln around 100 degrees F., and outside temp. is around 90 degrees. Glazed an hour later after wiping down the piece. I keep my glaze

bucket covered while dipping other glazes so water has not evaporated out. I stir before each dip and do not agitate it so as to not create bubbles but mixing it very well. I get about 10-15

large blisters and many small ones. I wiped over the small ones with my finger when dry (1 min. later) but the big ones collapsed leaving unsightly holes when I ran my finger over. Pop goes the

bubble. Two pieces I rubbed down any way and put in the kiln last night hoping the glaze will smooth out and not show the irregularities . Probably will show up in the finished piece.

Did I glaze too soon after pulling it out of the kiln? Maybe I am stirring the glaze too much? I don't think I am. Let me know any other thoughts. Thanks!

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Have you checked the viscossity of your glaze? I keep mine covered also but it slowly gets thicker and I have to check viscosity all the time with a viscosity cup

 

When I check mine I have a small window where everything works well. It's about 19 seconds (time it take fore viscosity cup to empty) if it gets to 20 seconds or longer I start having problems so just small amount amount thickness makes a big difference

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Have you checked the viscossity of your glaze? I keep mine covered also but it slowly gets thicker and I have to check viscosity all the time with a viscosity cup

 

When I check mine I have a small window where everything works well. It's about 19 seconds (time it take fore viscosity cup to empty) if it gets to 20 seconds or longer I start having problems so just small amount amount thickness makes a big difference

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Just a thought, but what about the ph balance of your water-is it really soft causing the glaze to be sudsy? One other though, did you thoroughly wash the pot with a damp sponge before glazing?

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I have been pondering this problem and wondering if you may have removed the vessels from the kiln too soon or did you rush the firing causing cracks to form in the bisque. You will find many schools of thought on this one but, it is overall best to let the kiln cool down before removal of the vessels. Let the vessels cool all the way down to room temperature, without propping.

I realize you are in a hurry. But firing and cooling down clay cannot be rushed. Hence the term 'haste makes waste'.

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First, thank you all for pondering my post. Mayco dry glazes do not have instructions for viscosity of glaze. I always wonder what it should be. You just add water and mix, pretty basic. I called them

today and a tech. was to get back to me but I guess he forgot, and viscosity was on my list of questions. Our water is pretty normal no suds. There are no visible suds or bubbles on top of the

glaze, save one or two. When I dip or pour its like the glaze hangs on the side and a bubble magically appears. If I pop a large one it leaves the bubble intact like a collapsed pot just sitting there with the

first layer of glaze with it. I washed the pots down last night and reglazed this am. No honker bubbles, just many pin hole bubbles that I rubbed out. I let the kiln cool down in bisque until it was 100 degrees and out

side temp was 90. One full day of cooling. I usually wipe the pieces down with plenty of water but this time I just wiped down with a damp sponge , and do not glaze for several hours after removing from bisque unlike

this time only waiting an hour. I probably needed to get the piece wetter and maybe thats why the bubble took the first coat of glaze with it. When I open the kiln tomorrow I will report back and the pieces I just

rubbed over with my finger. I hope its not like Christmas with no presents! Juli

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file://localhost/Users/julilong/Documents/IMG_0953.jpg

 

file://localhost/Users/julilong/Documents/IMG_0926.jpg

 

file://localhost/Users/julilong/Documents/IMG_0890.jpg

 

file://localhost/Users/julilong/Documents/IMG_0879.jpg

 

file://localhost/Users/julilong/Documents/IMG_0864.jpg

 

file://localhost/Users/julilong/Documents/IMG_0858.jpg

 

file://localhost/Users/julilong/Documents/IMG_0844.jpg

Not all were disasters some were worse than others. Tried to get photos of bubbles. Hope they uploaded.

Juli

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Please take this with a grain of salt as I mainly spray my glazes. I have found that with some glazes I get bubbles in the glaze coat that go right through to the body if the first coat(s) are fairly dry when I apply another coat. If the first coat is still so wet that I am not game to touch it, then I don't get bubbles when I apply the second( or more) coat(s). Timing is critical.

The solution may be to use one long dip or to ensure that the first glaze coat is still quite wet at the second dip. Worth an experiment or two methinks.

I suspect the cause is the body absorbing water and thereby expelling the air that it replaces. That air can bubble through a very wet coat but not through a semi dry "elastic" coat. Moz.

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Totally agree with Moz. Don't let those coats dry out. Big time bubbles = Posh Pet Bowls <_< . I go for a long count on the dip and make notes about the count in my glazing journal for interesting combinations for future reference. I've had pleasing results from layering and so forth but only in "damp" time. Don't revisit dipping or spraying when ware is dry. Heartbreaking.

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I will try your ideas about not letting the glaze dry out between dips. I always wonder how other potter organize their glazing process since I have not

watched others glaze. Since all my glazes are about the same color I does get confusing as to which pot has been dipped in what gaze and when. When I

start making notes and finding the piece in my journal by the time I look back for the next piece Im not sure where it is or what I was doing.blink.gif I would

love to watch other to see how they organize the whole process!! Do most of you use tongs, or fingers to hold pieces and if you use your

hands what do you use to get rid of finger marks? Brush, finger ect..? juli

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Ditto on the double dips. The first dip should be dry to the touch, but not completely dry. If the first coat dries completely, all sorts of funky things can happen with the second coat, like bubbling or falling off the pot. In my studio, I keep the glazes about the thickness of chocolate milk, and dip for a 6 count. Second dips go for a 4-6 count.

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So I spoke with a tech a Mayco. They have never heard of bubbles on bisque from glaze.ohmy.gif I know in fact i'm not unique! In the free gift/free download we received yesterday from

Emily Reason on this site "Ceramic Tool Techniques; Bringing the ceramic surfaces to life" she quotes, A matte or semi-matte surface suits the character of the

 

pieces. Each pot is dipped in a single glaze.

 

A narrow, deep groove will cause air bubbles to form

 

 

when the pot is dipped in glaze.

So I am not alone in this dilemma. I mentioned the suggestions given on this site, as well as asked about the viscosity of the glaze and measuring it in case that might be the problem, and he said

measuring was not necessary since you just mix the right amount of water to dry mix.dry.gif But I should have used distilled water. I must have missed that in the instructions. Not! He said I

must have contaminated the glaze somehow. I must have gotten some soap or something into the glaze from soap on my hands or from washing the bucket but the glaze must be contaminated. I did not get

soap in the glaze! Any girl knows from taking bubble baths the one way to ruin a good bubble bath is to drop a bar of soap in the bath! BUBBLES disappear!!! Instantly!

So its my fault, and every suggestion I mentioned from this site was not the cause.angry.gif I am going to try all your tips and remix the glaze batch with my electric mixer like I did when I mixed the glaze the first time.

I did not use the elec. mixer in subsequent batches just used a slotted spoon. Clean, but just rinsed in water not soap. Juli

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Ok, start again. Make new 'test' vessels be sure they are fired to cone 04 bisque. Cool them down completely in the kiln, to room temperature. Do not prop open to hasten the cool down, before removing the vessels from the kiln. Be sure to dampen the vessel before glazing. Mix the glaze the way you did the first time. Try dipping the glaze and see what you get. Let us know the results.

 

Here is something else you can try- if you have any unglazed bisqued vessels from that last firing, pour some water inside don't let any water get on the exterior of the unglazed bisqued vessel(s) and see if you notice any bubbles rising up from the vessel like you would see in a champagne filled glass. And also if the vessel begins to leak in spots on the exterior. Let me know what you see.

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  • 2 weeks later...

So I spoke with a tech a Mayco. They have never heard of bubbles on bisque from glaze.ohmy.gif I know in fact i'm not unique! In the free gift/free download we received yesterday from

Emily Reason on this site "Ceramic Tool Techniques; Bringing the ceramic surfaces to life" she quotes, A matte or semi-matte surface suits the character of the

pieces. Each pot is dipped in a single glaze.

 

I'm sorry to hear you are having this problem. I am a new potter myself, only 4 mos old. I wanted to just share this with you in case you haven't gotten your problem figured out, and to tell you of my dilemma with my first dipping glaze. I was on a schedule myself for an Empty Bowls project I was doing and I got tired of brushing on the clear glaze I was using. I purchased the same clear I was brushing on but in a dipping form which was Duncan's Pure Brilliance Clear. I bought a gallon of it and shook it up really well but I could see inside that it was thick looking. I shook and shook the container until I finally got it all out. I then mixed it with a paint mixer attachment to my drill. Mixed about 2-3 minutes. I thought it looked pretty smooth. I proceeded to dip my 04 bisque fired bowl in the glaze and immediately I knew something was wrong. The glaze looked rather thick, and not only that, it had BIG bubbles popping out everywhere. I stirred it up again, dipping the other side of the bowl, it did the same thing. I called my ceramic supplier where I bought the glaze and he told me I needed to check the Viscosity of the glaze. What??? I was sorta aggravated as like I said, I was on a time limit. So since it was too late, I had to drive an hour away again the next morning to purchase a viscosity cup. It's just over 5.00 for the cup. The owner showed me how to use it and I was so happy for the lesson. He had told me the night before I definitely didn't need to go any further until I got this cup. So I came home, mixed the glaze with (distilled water is what I was told to use) 1 cup of water at a time. Put the viscosity cup in the mixture and started my stop watch and when the glaze stopped dripping from my viscosity cup, I clicked my stop watch to stop. This is how you tell what the viscosity of your glaze is. If it was 22 seconds, I added another cup of water and did the test again. I did this until I got it down to 19 seconds. Like someone else said, if it's over 20, it just doesn't work for me either. I was shown that you dip the piece in and right out really quickly, give it a shake, and once that dries, you dip the other side. Since the glaze wasn't so thick, it didn't take long for it to dry. I just finished my first glaze firing in my kiln, and m bowls look beautiful. I plan to do a YouTube video on this soon so maybe I can help someone else. I hope this helped you.

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One thing that really helps my glaze application is wetting my bisque prior to application. I wet the pot in the process rinsing off all the particulate matter which will cause crawling or other glaze malfunction. I allow the pot to dry partially and then dip the pot in the bucket for a good long count depending on the thickness of the pot, maybe 3 for a thick pot, 8 for a thin pot. Consistency is a huge part of dipping glaze I like to have a heavy cream consistency. Something that hangs on my finger, but doesn't coat heavily. Having wet the pot prior to dipping allows the glaze to slide across the pot instead of making a coating instantly. It makes for a more fluid application and a provides a bit of leeway in glazing.

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Oh I forgot to mention that I also have started using witness cones to fire off my ware instead of relying on the kiln setter. I use the large Orton cones in cone packs that I make with clay and grog. The idea here is to allow myself some margin at the top to soak the kiln and then fire it back down slightly to allow the glaze to stop bubbling and heal over. This also allows me to shut down the kiln manually, allow it to cool and the turn it back on at 1900 or so and hold it for certain effects like the growth of crystals in iron red glazes.

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  • 1 year later...

I am glazing some pieces for a charity auction so time is of the essence so I am hoping someone can help me. I am using a mayco dry mixed glaze. Have used it

before without this problem. Cone 6. I am gently stirring my glaze before I dip or pour not agitating it. I am getting very large bubbles that are all over my

pots. These are not pin size that I can just rub down. Honkers! and lots of them. This is the second coat glaze. I've tried dipping slowly in and out, shorter dip time,

one to two seconds instead of three. I don't think any of the pieces had a long first dip (2-3 seconds). It is too late to get tech help from Mayco so maybe this happens

to others and someone can suggest a solution. I have already had to wash off glaze completely on several pieces because after I popped the bubbles It was a

mess. Let me know If you need any more info. I hope to glaze these this eve. Thanks!!!!! Yes, I am a newby.

 

 

Here is the answer to your problem. I just became a member in order to be able to reply. Make a very fluid glue of wall paper glue or potatoe flour glue. One teespoon in 200 ml water, disperse, heat gently, ready.

Now you can dip the shard (green or prefired) in the glue and with a brush make it even. Let dry. In this way you havec closed the bigger holes where normally the air comes out. During dipping, the water enters more slowly the shard and you give more time to the compressed air to get out. The screen of glue prevents also the air to come out. On YouTube you can see what happens. Go to Piet Reijnen on YouTube or air bubbles in glaze dipping. Greetings from France.

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  • 7 years later...

I've been having bubbles form on my pots during glaze application as well. Sometimes they seem to heal during the firing, sometimes not. During my last firing I tried a slow cool down from cone 6 to 1400F. This seemed to help but I'd rather eliminate them during application. I usually try to brush the most egregious ones with my finger before firing but that is time consuming and sometimes I brush too much leave bald spots on my pot. 

I've been bisquing to 05 so I'll try 04 and see if that helps 

I generally wipe the pots out with a damp sponge to get rid of dust but it sounds like I should try washing/wetting the pot more before application. 

Have folks experimented with/ have more info about this potato starch glue method? 

On 12/25/2012 at 5:08 AM, Keramos said:

 

Here is the answer to your problem. I just became a member in order to be able to reply. Make a very fluid glue of wall paper glue or potatoe flour glue. One teespoon in 200 ml water, disperse, heat gently, ready.

Now you can dip the shard (green or prefired) in the glue and with a brush make it even. Let dry. In this way you havec closed the bigger holes where normally the air comes out. During dipping, the water enters more slowly the shard and you give more time to the compressed air to get out. The screen of glue prevents also the air to come out. On YouTube you can see what happens. Go to Piet Reijnen on YouTube or air bubbles in glaze dipping. Greetings from France.

 

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Are there bubbles on surface of glaze after stirring in the bucket? If so these bubbles can appear on pot when dip glazing.

If so you can dissipate them by spraying  the surface of glaze in bucket with hairspray.

You can also fettle the bubbles after glazing prior to firing.

Have you tried a thinner application of glaze?

Test with a thinner application.

Measure Specific gravity when got where you like it.

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