Pottery beginnings

HorseloverFat

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I tend to keep a pot of slip per clay I use.
Yes sir... same here.

I strain it to remove the grog.. and any non-soluble particles in the suspension... Clay shrinks.. grog doesn't.. so If i'm ADDING a moisture layer.. I want to be ALL water.. to keep the distribution even.. and drying consistent.

So now I strain the slip, treat it like brush-on water, and actually go a touch lighter than I used to.
 

sorce

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Biggest pot I've made so far. (10x8 inch)
Left it to dry a bit over night in a plastic bag before attaching the feet and a hairline crack appeared on one if the corners! 😬

Smoothed it over. Here's hoping it survives the bisque... (any tips on how to handle cracking while drying? First time its happened to me. I dry as slow as i possibly can most of the time)

This one's destined for a nice grey or orange/brown glaze.

Is the crack visible in the back right corner?

There is something to be said about how "slow drying" isn't just "slow drying".
When enclosed, there is also a redistribution of water, depending how tightly (footless on what type of surface?), this can mean a bottom slab that was already properly shrunk, expanding again, then pulling the walls apart when it reshrinks.

For all the no good reasons people believe in "s-cracks" at the bottom of thrown rounds, it is truly caused by the middle staying wet longer than the edge.
When the edge dries/shrinks first, especially in the strong shape of a round, the center can't shrink wholly, so it relieves it's stress and gets it's shrink.
20220206_093917.jpg

This is to say, it is APPROPRIATE to have the edge of our pots the last thing wet, so it is slightly backpedaling to redistribute that water.

Appropriate drying isn't necessarily slow OR even.
Appropriate drying is what we must find for ourselves.

When all of our slabs are "dry", or mostly shrunk leather hard, and our joints are the last thing to shrink, we are in a *good physical position as far as clay action and avoiding "drying" cracks....
20220206_094914.jpg

But it does open up the easy possibility of handling cracks, especially when applying feet, which tends to rewet the joints.

It could be something as simple as one drop of water running down that spot, but I think these considerations may help you figure it out.

The shape of that particular corner and how it would want to shrink both in and out is slightly contradictory to "*a good physical position as far as clay action and avoiding "drying" cracks".

Nice.

Sorce
 

penumbra

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I actually seldom use slip. I just add a tiny bit of water to the areas, scratch it up and join. If clay is too dry it can cause problems. Then I dry the entire piece slowly and I use a hand sprayer on the areas where joining takes place. I may spray the area a few time during the drying time, not to point of run off but just a gentle spray to prevent drying too fast.
When I do use slip for joining, I like to thin the slip with vinegar instead of water.

BTW, very nice looking pot.
 

HorseloverFat

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When I do use slip for joining, I like to thin the slip with vinegar instead of water.
Whoops! should've mentioned this as well.. this is what I usually do for STRONGER bonds.. OR for structures where I won't be able to apply as much pressure.

:)
 

sorce

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I'm anti slip too, like that black shit they put on skateboard decks.

Especially if made a different consistency then what is being joined.
Truth. .I don't even trust the difference in bacterial numbers between out clay and jarred slip, let alone all the stuff that actually matters.

Plus it's a waste of time.

Sorce
 

andrewiles

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I like to thin the slip with vinegar instead of water.

I just ran into a comment by Phil on this. He wasn't a big fan, though I think he admitted to just hypothesizing rather than knowing for sure. Starting at 12:48:

Also, there's something about the word "flocculating" that's... disconcerting.
 

CodeMonkey

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Is the crack visible in the back right corner?

...

Sorce

Only just found time to get back to this thread.
Thanks for the detailed info as always Sorce. The crack wasn't visible in the photo, as I had already "fixed" it.

I think the most likely culprit is as you allude to. Some parts drying slower than others.
Also of note, that I hadn't considered. While this pot was drying I started some refurb work which resulted in a lot of dust in the adjacent rooms. Concrete and plaster dust. Although the pot was loosely covered most of the time, this stuff get's everywhere.
 

CodeMonkey

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Managed to find time to do a glaze firing this weekend.
Here's a few photos.

Some things went well. Others not so much.
  • I had stained the feet of a couple of the pots (in particular the large grey one) pretty dark, which doesn't seem to have taken. Kind of disappointing as the buff conflicts with the grey
  • One of the grey ovals glaze completely crawled off one side of the pot! My working theory is it was too thick. I noticed this when applying it but hadn't expected this result. Does this seem likely?
  • Running on the red pot has hidden the feet.
  • Attempted to wax the internal edges to get a crisper glaze line. This didn't go well. Any tips?
Does anyone have any constructive criticism on things I could improve? It would be much appreciated as always!
 

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sorce

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I think they're wonderful.

The buff grey works fine.

Is the crawler a combo that was perhaps applied backwards? Seems one rejected the other and somewhat flaked off before melt?

I think glaze on the inside of a rim is overated in total. You never see a tree potted proper for show not having that quarter inch occupied by moss. Crisp shmisp.

Sorce
 

CodeMonkey

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Is the crawler a combo
It wasn't. Seems odd that half of it stayed on. It was a glaze I tested previously on the same clay and was fine. I'm guessing I should have adjusted for water evaporation though.

The thickness is the only thing I can think of that was different.
 

CodeMonkey

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Wax works, tape, sponge it off after application. Are you spraying or brushing the glaze on?
These were all brushed.
I might try taping before the wax next time.

I kind of agree with Sorce about it not being that important as you won't see it, but at the same time think it adds a nice finishing touch to the unused pot.
 

mwar15

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These were all brushed.
I might try taping before the wax next time.

I kind of agree with Sorce about it not being that important as you won't see it, but at the same time think it adds a nice finishing touch to the unused pot.
I do it sometimes, I like the fade look you get with spraying
 

CodeMonkey

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I do it sometimes, I like the fade look you get with spraying
I've not tried spraying and it's not a technique I've really looked into.
What do you use to spray the glaze?
 

sorce

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Why is this significant in your mind?

The context was meant to define it as insignificant.

I don't even trust the difference in bacterial numbers between out clay and jarred slip, let alone all the stuff that actually matters.

The way I see it, if you have all the insignificant things buttoned up, mistakes with significant things become easier to identify and it keeps them from being fatal mistakes.

It's like the mechanical working definition of @Carol 83 quoteline.

Sorce
 
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