Would dipping the nails in wax solve the size and surface tension issues? I work in beeswax mostly, but paraffin would coat the nails. Or perhaps a silicone spray on the nails would work also and be cleaner.
I was thinking of rubbing wax on them. Silicone spray is an interesting idea! I want to move away from the nails to some heavy gauge wire to get the right size, so finding a coating for that would be useful.
@@PotterybyKent @Nighthawkinlight "A Better Way to Waterproof Fabric" has a recipe for water resist that work exceptionally well on fabric (paraffin wax with mineral oil). I reckon it can be tweaked to a thinner consistency that sticks a, well, thin conformal coating on those nail so that can be retracted w/o clogging the left-behind hole with slip.
@@PotterybyKent It just popped up in my mind that wooden things (bamboo skewers, pencils ends, dowels - round or shaped in a prism), could work better than metals with the paraffin wax + mineral oil, as long as you impregnate them while the mixture is warm/hot. I'd try to sand them with a fine grit then let them soak in molten wax/oil for a couple of hours, get them out while hot, wipe the excess wax then hang them to cool, pointing down the end meant to go inside the pot/slip (a cloth pin or a paper binder clip may do the hanging trick)
I like the idea of the wax plug through the mold wall. I think that you could push in the plugs from the outside so they would protrude farther than your wall thickness, and come time to de-mold, you could just push the plugs all the way through to the inside. It would be interesting to see the result of such a method on the inside surface... I wonder if the hydrophobia of the wax plug would create the opposite result as you found with the nails (a sink rather than a mound) The plugs could be solid wax, waxed candle wick, or some wood dowel soaked in molten wax. I'm not sure silicone spray wouldn't also soak into the adjacent plaster affecting its performance. There might be a source for wax rods for use in jewelry investment casting.
It’s clear from your experiment that plaster surrounding the clogged areas is pulling moisture from more than just the slip directly above where it contacts. It pulls the closest moisture which is at times where the waxed areas have slip. My thought would be to use wax discs slightly thicker than you wall thickness and melt apply them to the mold wall. That way, there’s no slip there to pull. And you can just melt that wax off on bisque. Problem is, the piece won’t pull with the wax melted to the mold wall, so you’ll need to put the whole mold (piece and all) into an oven the release the wax from the mold before you pull. You’ll probably know where the piece was from residue for putting on the next discs for the next casting.
I think that's a good observation! The water is migrating through the deposited clay into the plaster. The wax disk idea is an interesting one. However the slip cast piece can't be left in the plaster mold that long - it will end up cracking. I'm guessing extra heat wouldn't help on that front either. It needs to be pulled relatively quickly so the moisture in the wet clay can homogenize and the water can evaporate from both sides more evenly.
Perhaps multiple deposits of the factory wax to build up their height would make actual holes. But that would be labor intensive to an extreme. It's a definite challenge.
Perhaps a waxy plastic such as polyethylene or polypropylene could be used to make the pins, rather than using wax itself. If it works, the pins would be rugged enough to be reusable, and you could make a set of a specific length. Finding plastic rod made of these materials might be tricky, though you could test to see if it would work by using glue sticks for hot glue guns, or maybe resin filament for small holes...
@@PotterybyKent You're right that teflon rods would be good, but they're much too expensive. Something ultra-cheap that might work would be plastic straws cut to an appropriate length. I suspect these are made from either PE or PP (most cheap disposable products are), but you'd need to test to see if the slip would drain from the plastic as well as it does from wax. The obvious problem with a straw is that it is hollow, but you could fix that by filling it with another substance before cutting it into pieces. Many things might be suitable, but silicone caulk or perhaps expanding polyurethane foam (supplied in aerosol cans and used for filling cracks) would do the job. In fact, a plastic straw might function as a very good mould to make rods of pure silicone! Fill one with caulk and then carefully score the straw lengthwise, and you have a silicone rod that probably won't stick to anything.
@@PotterybyKent Another thought would be that if you use a straw to create silicone rods, but the result is too flexible, you could likely fix that by putting a steel core at the centre of the straw before filling it with silicone. Straight sections of steel taken from a cheap metal coat-hanger would be suitable for this, and if the steel isn't perfectly centred, it wouldn't really matter as long as it is fully coated. Numerous other metal objects (brass rod, etc.) could also be used for this, though it would be needlessly expensive unless you already have some on-hand.
@@PotterybyKent No, I agree that metal alone likely wouldn't work, but if it is surrounded by a layer of cured silicone, the results would probably be good. A steel coat-hanger has a diameter of about 1/16th of an inch, and the internal diameter of a typical straw is at least twice that (1/8 - 1/4"). Using a plastic straw as a mould, with a central core of steel (coat-hanger), and surrounded by silicone, should give you a reasonably rigid but clay-repellent rod that could be cut into pieces to provide what you need. You'd need to check that the silicone doesn't bond too tightly to the plastic straw, but if it does that problem could likely be fixed by coating the interior with Vaseline or talcum powder.
![[#2024MAMA] G-DRAGON - 무제(Untitled, 2014)+POWER+HOME SWEET HOME+뱅뱅뱅+FANTASTIC BABY | Mnet 241123 방송](http://i.ytimg.com/vi/Ox29z5Nf1Uk/mqdefault.jpg)
Would dipping the nails in wax solve the size and surface tension issues? I work in beeswax mostly, but paraffin would coat the nails. Or perhaps a silicone spray on the nails would work also and be cleaner.
I was thinking of rubbing wax on them. Silicone spray is an interesting idea! I want to move away from the nails to some heavy gauge wire to get the right size, so finding a coating for that would be useful.
@@PotterybyKent @Nighthawkinlight "A Better Way to Waterproof Fabric" has a recipe for water resist that work exceptionally well on fabric (paraffin wax with mineral oil). I reckon it can be tweaked to a thinner consistency that sticks a, well, thin conformal coating on those nail so that can be retracted w/o clogging the left-behind hole with slip.
Thanks for the tip @col0342 - I'll need to look
@@PotterybyKent It just popped up in my mind that wooden things (bamboo skewers, pencils ends, dowels - round or shaped in a prism), could work better than metals with the paraffin wax + mineral oil, as long as you impregnate them while the mixture is warm/hot. I'd try to sand them with a fine grit then let them soak in molten wax/oil for a couple of hours, get them out while hot, wipe the excess wax then hang them to cool, pointing down the end meant to go inside the pot/slip (a cloth pin or a paper binder clip may do the hanging trick)
I like the idea of the wax plug through the mold wall. I think that you could push in the plugs from the outside so they would protrude farther than your wall thickness, and come time to de-mold, you could just push the plugs all the way through to the inside. It would be interesting to see the result of such a method on the inside surface... I wonder if the hydrophobia of the wax plug would create the opposite result as you found with the nails (a sink rather than a mound)
The plugs could be solid wax, waxed candle wick, or some wood dowel soaked in molten wax. I'm not sure silicone spray wouldn't also soak into the adjacent plaster affecting its performance. There might be a source for wax rods for use in jewelry investment casting.
Looking in the jewelry space for wax rods is an interesting thought!
It’s clear from your experiment that plaster surrounding the clogged areas is pulling moisture from more than just the slip directly above where it contacts. It pulls the closest moisture which is at times where the waxed areas have slip.
My thought would be to use wax discs slightly thicker than you wall thickness and melt apply them to the mold wall. That way, there’s no slip there to pull. And you can just melt that wax off on bisque. Problem is, the piece won’t pull with the wax melted to the mold wall, so you’ll need to put the whole mold (piece and all) into an oven the release the wax from the mold before you pull. You’ll probably know where the piece was from residue for putting on the next discs for the next casting.
I think that's a good observation! The water is migrating through the deposited clay into the plaster.
The wax disk idea is an interesting one. However the slip cast piece can't be left in the plaster mold that long - it will end up cracking. I'm guessing extra heat wouldn't help on that front either. It needs to be pulled relatively quickly so the moisture in the wet clay can homogenize and the water can evaporate from both sides more evenly.
Perhaps multiple deposits of the factory wax to build up their height would make actual holes. But that would be labor intensive to an extreme. It's a definite challenge.
It's tricky for sure!
Perhaps a waxy plastic such as polyethylene or polypropylene could be used to make the pins, rather than using wax itself. If it works, the pins would be rugged enough to be reusable, and you could make a set of a specific length. Finding plastic rod made of these materials might be tricky, though you could test to see if it would work by using glue sticks for hot glue guns, or maybe resin filament for small holes...
TPFE would be best. But for the number of holes I had, it was too much $ to justify.
@@PotterybyKent You're right that teflon rods would be good, but they're much too expensive. Something ultra-cheap that might work would be plastic straws cut to an appropriate length. I suspect these are made from either PE or PP (most cheap disposable products are), but you'd need to test to see if the slip would drain from the plastic as well as it does from wax. The obvious problem with a straw is that it is hollow, but you could fix that by filling it with another substance before cutting it into pieces. Many things might be suitable, but silicone caulk or perhaps expanding polyurethane foam (supplied in aerosol cans and used for filling cracks) would do the job. In fact, a plastic straw might function as a very good mould to make rods of pure silicone! Fill one with caulk and then carefully score the straw lengthwise, and you have a silicone rod that probably won't stick to anything.
@@PotterybyKent Another thought would be that if you use a straw to create silicone rods, but the result is too flexible, you could likely fix that by putting a steel core at the centre of the straw before filling it with silicone. Straight sections of steel taken from a cheap metal coat-hanger would be suitable for this, and if the steel isn't perfectly centred, it wouldn't really matter as long as it is fully coated. Numerous other metal objects (brass rod, etc.) could also be used for this, though it would be needlessly expensive unless you already have some on-hand.
Metal didn't work as I thought it might
@@PotterybyKent No, I agree that metal alone likely wouldn't work, but if it is surrounded by a layer of cured silicone, the results would probably be good. A steel coat-hanger has a diameter of about 1/16th of an inch, and the internal diameter of a typical straw is at least twice that (1/8 - 1/4"). Using a plastic straw as a mould, with a central core of steel (coat-hanger), and surrounded by silicone, should give you a reasonably rigid but clay-repellent rod that could be cut into pieces to provide what you need. You'd need to check that the silicone doesn't bond too tightly to the plastic straw, but if it does that problem could likely be fixed by coating the interior with Vaseline or talcum powder.