Dinnerware plates are driving me nuts!

[DMCosta]

So I'm on the quest to make proper dinnerware plates. I first tried handbuilding them using the G R Pottery forms and when I fired them almost all warped in firing. I recently made some nice thrown plates and just finished trimming them. I go to check on them today and every one is already warping. They're all ovaling or what I call lemon-ing out. They're basically at the middle of leatherhard now. I had them about 80% wrapped last night and intending on drying them to leatherhard slow and steady.  I'm using cone 6 Standard 710 brown clay and compressed them very diligently with my rib when throwing them. I'm far from a plate expert but have made others using various clay bodies and never had this issue. Do you think it could be this 710 clay?

I appreciate any help you can provide! 

[liambesaw]

Maybe the clay? How do you handle them once you've made them?

I let mine get to leather hard on the bat, and then pop them off and trim them.  Don't have issues with warping.  

 

[DMCosta]

I'm throwing them on the bat as well. I only 

3 minutes ago, liambesaw said:

Maybe the clay? How do you handle them once you've made them?

I let mine get to leather hard on the bat, and then pop them off and trim them.  Don't have issues with warping.  

 

I'm throwing them on the bat as well. I only move them off the bat when ready to trim. 

[Pres]

Could be the caly, but how do you turn them over for trimming? I have been throwing plates for several years, and find that if I lift with my hands at anytime they can warp in that direction. So I have a tendency of putting a clean bat over top of the cheese hard plate, and flipping it. I do not allow the plate to get leather hard on the bat, as the rim will be stiff enough even though the center is cheese hard. 

 

best,

Pres

[DMCosta]

27 minutes ago, Pres said:

Could be the caly, but how do you turn them over for trimming? I have been throwing plates for several years, and find that if I lift with my hands at anytime they can warp in that direction. So I have a tendency of putting a clean bat over top of the cheese hard plate, and flipping it. I do not allow the plate to get leather hard on the bat, as the rim will be stiff enough even though the center is cheese hard. 

 

best,

Pres

Good point that's a possibility I have seen a ton of videos where people flip the piece onto a clean bat. I didnt do that, I just lifted them off the bat which could have caused this problem.  I was able to flatten them back again since they're leatherhard but because of the clay memory I feel like when I fire them they'll resort back to bring warped. Sigh. 

[Bill Kielb]

7 minutes ago, DMCosta said:

Good point that's a possibility I have seen a ton of videos where people flip the piece onto a clean bat. I didnt do that, I just lifted them off the bat which could have caused this problem.  I was able to flatten them back again since they're leatherhard but because of the clay memory I feel like when I fire them they'll resort back to bring warped. Sigh. 

Just an add a good way to think about memory is most creases stretch the clay on the outer portion of the crease. Even put back in shape the particles are spread apart more than the rest of the clay. Sometimes putting it back works but often firing it makes its reflection come back. If it’s on the wheel and you can recompress everything with a rib or tool you stand a good chance of making all the particles even again.

[DMCosta]

30 minutes ago, Bill Kielb said:

Just an add a good way to think about memory is most creases stretch the clay on the outer portion of the crease. Even put back in shape the particles are spread apart more than the rest of the clay. Sometimes putting it back works but often firing it makes its reflection come back. If it’s on the wheel and you can recompress everything with a rib or tool you stand a good chance of making all the particles even again.

Thanks for the advice 

[DMCosta]

1 hour ago, liambesaw said:

Maybe the clay? How do you handle them once you've made them?

I let mine get to leather hard on the bat, and then pop them off and trim them.  Don't have issues with warping.  

 

I basically did the same, I let them get leatherhard on the bat then only removed them for trimming. 

[Mark C.]

I only flip plates or platters using a clean bat so they always stay flat-if you do not do this the clay will remember you warped them and warp again.

Never had issues  as they always are flat

Ceramics can get you in the details and its ALL DETAILS

step 1 throw plate on bat-cur off after throwing-leave on bat

step two once dry enough to flip -flip onto new bat. -when dry enough trim.

I tend to then let plate dry right size up on foot slowly until ready to bisque

More plates than I can recall done just this way-no warping-all porcelain  since 1985 stoneware before that-no warping

[DMCosta]

16 minutes ago, Mark C. said:

I only flip plates or platters using a clean bat so they always stay flat-if you do not do this the clay will remember you warped them and warp again.

Never had issues  as they always are flat

Ceramics can get you in the details and its ALL DETAILS

step 1 throw plate on bat-cur off after throwing-leave on bat

step two once dry enough to flip -flip onto new bat. -when dry enough trim.

I tend to then let plate dry right size up on foot slowly until ready to bisque

More plates than I can recall done just this way-no warping-all porcelain  since 1985 stoneware before that-no warping

That's great advice thank you.  So after trimming to get it right side up again do you flip it again using a bat?

[Mark C.]

When its dry enough to trim its stable enough to not warp-if you are trimming when its wet enough to warp you are trimming to wet.

so not I do not use a bat after trimming to flip it. I just pick it up.Its not wet then -just leather hard

[DMCosta]

48 minutes ago, Mark C. said:

When its dry enough to trim its stable enough to not warp-if you are trimming when its wet enough to warp you are trimming to wet.

so not I do not use a bat after trimming to flip it. I just pick it up.Its not wet then -just leather hard

Ok yeah makes sense it does keep it's shape after trimming. I'm not new to pottery but apparently new to making dinnerware plates haha

[neilestrick]

If you're not trimming them evenly-uneven between the center and the foot ring- they will warp/cup as they continue to dry past leather hard.

When I throw plates, I immediately cut the plate loose from the bat, and cover the rim with plastic strips (caution tape works great). This prevent the lip from drying faster than the center of the plate and raising. I leave them totally uncovered except for the rim for 2-3 days, however long it takes for them to firm up enough to flip.

[Mark C.]

My porcelain dries fast and evenly so its usually a two day deal from thrown to trimmed unless I cover them to slow them down.

[DMCosta]

Thanks everyone it seems my issue is likely that I'm not transferring the plate properly from the original bat to the wheel for trimming. I wasn't doing the flip technique mentioned I was just lifting it off the bat manually which may have been why I had the warping. I'm going to have to give it another go and hope I yield better results with your advice! 

[DMCosta]

2 hours ago, neilestrick said:

If you're not trimming them evenly-uneven between the center and the foot ring- they will warp/cup as they continue to dry past leather hard.

When I throw plates, I immediately cut the plate loose from the bat, and cover the rim with plastic strips (caution tape works great). This prevent the lip from drying faster than the center of the plate and raising. I leave them totally uncovered except for the rim for 2-3 days, however long it takes for them to firm up enough to flip.

This is really helpful thanks. They're trimming super well and even.  The way you only tape/cover the rim and leave the rest exposed is interesting I never thought of that. 

[Mark C.]

Here are some of my plates for an old post

They are all porcelain and have glazed bottoms and trimed feet-I also have some newer posts with photos of plate bottoms-They may be in my gallery if you want to see them there.

[Sorcery]

I reckon the tops are drying as the bottom is stuck to the bar, so the top has no where to go.

Sorce

[Roberta12]

In addition to all of the great advice given previously, if I think there is a chance a plate or tray will warp while drying, I have a selection of brown and white rice in their bags to place on the middle of the plate/tray while drying.  I have found that helps.  And in case of a pandemic where there might be shortages of beans and rice, you will have a supply!! 

Roberta