Washing Bisqueware Before Glazing?

[eloiseceramics]

I saw someone say that washing bisqueware before glazing can prevent dripping in the glaze fire because it makes it less absorbent when dipping in the glaze? Does anyone else do this? I'm worried it will make the glaze crawl or something weird.. Thoughts?

[oldlady]

your question sounds as if you are recalling two things and thinking they are one.  the term 'washing bisqueware" sends a message of someone with a sink full of suds scrubbing the pots.   and i do not get "dripping in the glaze fire", do not understand what is meant.  i am getting really old and language changes, i know.

 

to reduce some problems with glaze application and smooth out the results so crawling is not as likely, you merely dampen the bisque.  an example is to quickly dip each piece of bisque into a bucket of clean water and remove it.  set it aside until you are finished with all of them. then do whatever preparation you need to glaze them all, start with the first one you dipped and apply the glaze.  judgement is called for as you would not dip 100 pots and expect the last one to not be dry by the time you get to it.

 

this works well, especially in dry climates.  if you attempt to glaze a very dry bisque pot, the glaze will grab the dry surface and form cracks instantly.  that is the main reason for dampening the work.  those cracks become crawling if you go ahead and fire the pot.  sometimes, you cannot actually see the cracks and other times they are so pronounced you will immediately know you are in trouble.  no matter what application method you use, the dry bisque will grab the glaze if you brush it on, dip it or spray.

[GEP]

This advice is not something that applies universally to all glazes, but might apply to some glazes. Such as glazes that tend to run when thick, or glazes that are mixed up too thick in the bucket.

 

Like oldlady said, dampening bisque pots is a common technique. I do it when I want a thinner application of glaze. I run the bisque pots under a running faucet, and make sure they sit at least 15 minutes before glazing. You don't want the pot to be soaking wet or unevenly wet, so the 15 minutes allows the water to distribute itself and the surface to dry.

 

I have never seen this technique result in crawling glazes, just a thinner application of glaze.

[Marcia Selsor]

I do it too. I agree with Mea and Old Lady that it 1. just cleans any dust off the surface--which avoids crawling problems from dirt and 2. does not suck the glaze into a dry surface so there is more control when dipping in the glaze. You can use a damp sponge or rinse in a bucket of clean water or under a faucet and let it dry a bit.

Marcia

[Mark C.]

I rarely do it-only if I need to wash off glaze or want to have less glaze thickness.

If my pot is dusty I blow it or soft brush it clean.

Most of my bisque ware is glazed dry as I know what the glaze thickness will be at that state. When you wet the wares they absorb less and you will need to learn what this thickness will be.

[Marcia Selsor]

Mark, I guess that all depends on knowing your glazes and knowing your usual consistency of your glaze.

Knowing your materials is the key to how you work.

Marcia

[Mark C.]

The last point is what Oldlady said about 100 pots except I'm processing (glazing ) way more than that on glaze day. 

When you glaze up 35 cubic feet of wares in a day washing pots would bankrupt me time wise.

I keep them clean as the stay in bisque kiln until the day before glazing or come out on glaze day. If they hang in studio I cover them with paper. Or store them glazed as the dust burns off clean-this tip works well.

[rakukuku]

When I was a student a zillion years ago we were taught to rinse off our pots before glazing. It was a dry climate due to winter heating.   When I moved to norther cal, everyone thought I was nuts when I asked about rinsing.  I do sponge off my pots to get rid of dust but no reason to rinse them to decrease absorption of glaze.    May be climate issue.   rakuku

[curt]

I rinse mine under a running faucet briefly, then let them sit to dry for 30 mins or so.  Unlike Mark, my pots are often out on shelves for weeks at a time gather dust, being handled, etc. so rinsing restores the original bisque surface somewhat.  And also unlike Mark, my pots are going to face glazes whose consistency, thixotropy, specific gravity, etc, (rheology!) are all over the map from glaze to glaze, so the rinsing helps stop "over-application".  If I feel like I need more glaze, I can always double dip, but once it is one there, if it is too thick, you really just have to wash it all off and start agan.   For those in a "club studio" situation, getting people in the habit of rinsing also compensates for those beginners putting on too mucy glaze, double or triple dipping, which just leaves glaze running all over the kiln shelves. 

 

Rinsing can also help address one problem that people seem to have, which is air bubbles popping out from the clay body through the wet glaze just after they have dipped it (one reason to spray everything?)  Since rinsing fills many pores with water, it is essentially pushing out air in pore pockets and replacing it with water.  This can be helpful...

[Pres]

I don't run my pots under a faucet, but have large bucket ow water that I use a large shaped sponge to sponge the inside and outside of the pots. Set them aside for about 5 min. before base dip glazing. I find that I have evener surfaces of glaze coverage, less pin hole bubbles in the unfired surface, and evener absorption of glaze around joins like handles and textural decorations in the pot. This helps me with the first coat of glaze, as the others are dribbled, sponged, splattered or sprayed over top with brushwork afterwards.

 

best,

Pres

[oldlady]

thanks, all for agreeing with me somewhat.  one other thing that happens if you dip into a clean bucket of clean water is that when it is all over, there are usually tiny crumbs of clay in the bottom of the bucket.  i never know where they come from but i am glad they are in the bucket and not on my pots.  maybe some come from signing on the bottom or bits that were carved off but the tiny bits did not fall away from the pot.  but that is the time to make sure that whatever you glaze is what you want.

 

years ago i found the results of many potters dipping into a large communal trash can size bucket when i sieved the glaze.  for the first time in ages, apparently.  there was even a whole bisque cup that must have fallen into the bottom and stayed there with all the crumbs.  about a cupful that time.

[Marcia Selsor]

old lady,

I have found those crumbs in the glaze buckets in the classroom glazes when routinely sifting them. Who knows where they come from, but better in a bucket of water than the bucket of glaze.

Marcia

[Rae Reich]

I don't run my pots under a faucet, but have large bucket ow water that I use a large shaped sponge to sponge the inside and outside of the pots. Set them aside for about 5 min. before base dip glazing. I find that I have evener surfaces of glaze coverage, less pin hole bubbles in the unfired surface, and evener absorption of glaze around joins like handles and textural decorations in the pot. This helps me with the first coat of glaze, as the others are dribbled, sponged, splattered or sprayed over top with brushwork afterwards.

 

best,

Pres

Yes! Dipping in water eliminates those pesky bubble voids at handles and attachments and intricate do-dads. Especially useful when dipping tall pieces to lessen glaze build-up on the part that's immersed longest.

[Harvest]

Hello. Has anyone heard of microwaving your  wet bisque pot to dry it a bit before glazing? Side affects of this if any?

[Benzine]

I rinse all my bisque, under hot tap water.  It seems to get all the "kiln dust" off.

I also advise my students to do the same, because there projects can sit around for a while, and get covered in dust, clay, other glazes, etc.

[Mark C.]

5 hours ago, Harvest said:

Hello. Has anyone heard of microwaving your  wet bisque pot to dry it a bit before glazing? Side affects of this if any?

well thast a bad idea as it could cuase it to  fail(explode or crack) if on to high-steam is a powerfull thing-you could test it out on something small 1st.

[Callie Beller Diesel]

@Harvest if you’re worried about the amount of water a pot will absorb in a rinse, you could always just wet sponge your pieces down rather than immersing anything. 

I would not microwave anything to dry it out. Oven or bbq on the keep warm setting, maybe.