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17 hours ago, shawnhar said:

I just cut holes in the side at the bottom. Going to pick up a hole tool tomorrow, I tried to use one of my drill bits and they came out terribly messy. 

 

@shawnhar, if the clay is isn't too dry you can use a straw to cut the holes with. Snip the end of the straw at an angle, the clay you are removing stays in the straw which you can cut off after you've finished punching holes. (milkshake straws are a good size or for bigger holes bubble tea straws)

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7 minutes ago, Min said:

@shawnhar, if the clay is isn't too dry you can use a straw to cut the holes with. Snip the end of the straw at an angle, the clay you are removing stays in the straw which you can cut off after you've finished punching holes. (milkshake straws are a good size or for bigger holes bubble tea straws)

Brilliant!

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52 minutes ago, Min said:

@shawnhar, if the clay is isn't too dry you can use a straw to cut the holes with. Snip the end of the straw at an angle, the clay you are removing stays in the straw which you can cut off after you've finished punching holes. (milkshake straws are a good size or for bigger holes bubble tea straws)

I use a short piece of dowel or stick to clear the straw when punching multiple times. 

Saving any size plastic straws I come across now....an endangered species ;)

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I really like the Kemper hole cutter more than the brass ones. I also use various size bamboo skewers and knitting needles, depending on applicability.

 

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I'm using drill bits for holes - drains, and particularly, hollowing out knobs; I like the clay spiraling out! ...if the clay is a bit damp, then the chips stick in the flutes, hence a hole may take a few steps... from there, a larger bit makes a nice chamfer. I'll start with pilot hole, then move up to a larger bit...

Cutting fluid, that's a good idea Chilly!

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Drill bits are less likely to crack the piece, since they remove material as they make the hole. Hole cutters force the clay to expand to make room for the wall thickness of the cutter. If the clay is too firm, or the hole is too close to an edge, it will crack.

The biggest problem with all holes, and one that many, many people do not address, is the sharpness of the edge of the hole. Rubbing out the edge with a sponge or finger takes forever. The simplest solution I've learned is to use a countersink LIKE THIS ONE. Just twist it lightly in the hole once it's just past leather hard, and it will knock off the sharp edge. I use this on all my colanders, and I can do all the holes in a matter of a minute. It puts a nice little bevel that looks rounded once it's glazed.

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I've used countersink on small holes - the angle is steeper, hence I prefer a larger drill bit to chamfer larger holes...

Edited by Hulk
specific-ity, specificity, I'm just loaded with that, In this one word is the epitome of the aristocrat!

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Engineering alert!

Just a crazy add here and this has happened to several folks drilling holes in flat clock faces. Our best theory thusfar: It turns out clay acts like many materials with stress developing as  result of the drilled hole. I had a friend that made clock faces, very flat and often thin for their overall size. On several occasions the faces split completely in half during the glaze firing (Like 1/2" apart as the stress ejected each half). This can be common and present itself in flat faced items and likely presents itself similar to the stress and strain we find on other drilled materials. Our solution was to thicken the slab in the area of the bored hole one to two diameters larger than the hole …….. (reinforce with a washer over it, how original we are!))

The hard lesson: always chamfer and smooth any hole cut in the clay so as not to provide an easy path for the material to begin cracking. The forces around it will be real and will appear, so always do your best. Kind of like concrete shrinkage cracks developing at an inside corner.

Kind of geeky but good clay construction practice likely will help avoid disappointment later. Nice to see everyone has a favorite way to chamfer these.

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cracking can also occur in flat slabs with deep indentations.  picture the typical cookie cutter with a shape that has sharp angles, like the deep notch in heart shaped cutters.   if you cut something like this, a rounded dowel or the used pencil eraser that is rounded over, can be pressed into the angle to compress the clay.  

Edited by oldlady
clarity

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21 minutes ago, oldlady said:

cracking can also occur in flat slabs with deep indentations.  picture the typical cookie cutter with a shape that has sharp angles, like the deep notch in heart shaped cutters.   if you cut something like this, a rounded dowel or the used pencil eraser that is rounded over, can be pressed into the angle to compress the clay.  

Could you compress from inside the cookie cutter instead?  Kind of like a hamburger press?  Would probably give neater lines with less hassle

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sorry i was not clear.  i do not mean pressing down vertically on the whole clay surface, i mean forcing the sharp indentation into a curve, not a sharp angle.  that means shoving the dowel horizontally along the work surface  into the deep angle to round it.

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Snow day--working on turning the Meet Mr. Hammer bin (by the window) into shards for drainage in the bottom of pots, the  inventory/photo task bins, set up for my helper to process,  & green smalls, dry and ready to add to my pending bisque load.

 

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Been firing some more tests soluble salts and consecutive followups on good leads from tests. Pots on the left were fired at various temperatures in saggars and foil saggars. pots on the right were retired at 1700F. Additional coats on salts were added.

 

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Nice holder!

Just catching up on custom orders for mugs and underglazed stuff. Also working through fixing an existing Bristol glaze for the studio . Arrrrgh dislike these glaze recipes  but almost done, I think.

After spraying countless ornaments  and now these little mugs, cups, treasure boxes I think  I need a throwing break from this stuff! Took a picture of myself spraying and I do not appear to be excited. LOL

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Running conduit under the house today, WHAT A CHORE.  24 inches of clearance and I'm a big 220lb 6'2" monster so not a whole lot of room to work.  Hopefully this pays off in the next few weeks and I'll be firing an electric kiln!!!

Wire arrives via UPS sometime next week and I can run the wire and call the inspector if everything goes swell.  Fingers crossed I did everything OK, it looks good anyway.

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Aaah, memories! Our first home had a low crawlspace - get between joists to roll from front to back.

The word "swell" reminds me - suggest long shirtsleeves and pants, both secured with rubber bands (plural), and pants tucked in socks, collar fully buttoned up, and look look look before entering. I find both black widows an' fiddlers (brown recluse) in the oddest places, e.g. in the garage/studio, right where I'd put my hand; tucked up in the garbage can hand hold; outside the front door, between knee and forehead level. 

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For folks happy to be rolling in the mud, or rolling mud,  you wouldn’t think they wouldn't be so sensitive to the great outdoors and it’s inhabitants.

looks like these electric quotes are going higher.  Here is to hard working trade people everywhere!

LOL

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