Slip casting a cup from a one part plaster mold — Transcript

Full transcript

1. 0:02okay in this video
2. 0:03we are um we have our our
3. 0:06um one part mold here and um we're gonna
4. 0:09start
5. 0:10pouring some cups and so i'm gonna walk
6. 0:12you through a couple of things to think
7. 0:14about here
8. 0:16first you want to make sure that you
9. 0:18have your casting slip mixed up really
10. 0:20well
11. 0:21um as it sits for a little while you'll
12. 0:23see it'll kind of
13. 0:24start to stiffen at the top so just make
14. 0:27sure you have your
15. 0:37and then the other thing that i do is um
16. 0:40i try to keep the side of this bucket
17. 0:43you know as clean as you can because
18. 0:45what you don't want is you don't want
19. 0:46things um you know little little bits of
20. 0:49the slip
21. 0:50uh drawing on the side of the bucket and
22. 0:51then falling in to the bucket
23. 0:53so i try to keep that as clean as
24. 0:56possible and um
25. 0:58okay so now that i have this stirred up
26. 1:01i'm going to
27. 1:02um pour the casting slip
28. 1:05into both of these and what you want to
29. 1:08do is you want to try to make sure that
30. 1:10you can pour it in one go so you don't
31. 1:12want to have to stop
32. 1:13and refill in the middle of the pour
33. 1:15because then you'll get a line
34. 1:17you know wherever you stop on your mold
35. 1:18so what i like to do is have a sponge
36. 1:20handy
37. 1:21i'm gonna get a full scoop of this and
38. 1:24then i'm just gonna
39. 1:25um kind of take the sponge and kind of
40. 1:28clean this
41. 1:29the sides up a little bit so it doesn't
42. 1:31drip as much
43. 1:32you know the cleaner that you can be
44. 1:34with this the easier
45. 1:36and so i'm just gonna kind of pour this
46. 1:40all the way in and now as soon as i said
47. 1:42that i'm dripping across the back
48. 1:45and what i'm going to want to do here is
49. 1:47i want to pour this right
50. 1:48up to the top i want to um
51. 1:52you know i want to try to get it as
52. 1:53close to the top without going over
53. 1:56as i can you know
54. 1:59just like that okay now that level will
55. 2:03will sink a little bit as i as i wait
56. 2:06here so
57. 2:07i'm going to then try to or i'm going to
58. 2:09get another scoop here
59. 2:11and then i'll pour this one here
60. 2:19okay so now and do the same thing i'm
61. 2:22going to bring this right up here to the
62. 2:23top
63. 2:25and try not to go over
64. 2:28so then i will empty this
65. 2:32set this aside and um
66. 2:36now i'm gonna wait 10 minutes uh for
67. 2:39both of these so i'm going to set this
68. 2:41timer um
69. 2:42and uh i'm going to set the timer for 10
70. 2:45minutes
71. 2:46and then um while i am waiting for that
72. 2:49um
73. 2:50the layer is going to go down a little
74. 2:51bit sometimes you have to top this off a
75. 2:53little bit
76. 2:54um but in these particular ones i
77. 2:57haven't been
78. 2:57having to do that but um so we'll stop
79. 3:00the camera here and then we'll come back
80. 3:02in 10 minutes
81. 3:06okay so now uh these two
82. 3:10molds have been sitting with a slip
83. 3:11inside of them for 10 minutes
84. 3:14and what's happening is is that the
85. 3:17plaster is uh
86. 3:18is absorbing moisture and so what that
87. 3:21does is it sort of wicks
88. 3:22um the moisture to the edge of this
89. 3:26uh of the cup that's in there and is um
90. 3:28you know creating a thickness here
91. 3:30that you can kind of see the thickness
92. 3:32of the vessel
93. 3:34now the longer you leave it in there the
94. 3:35thicker it's going to be
95. 3:37and so you might find that after 10
96. 3:39minutes your particular mold
97. 3:41might be too thick or too thin and also
98. 3:44that time will change as the mold
99. 3:47um you know gets really saturated with
100. 3:49with moisture
101. 3:51really when you're casting like this
102. 3:52you're you know it's pretty good if you
103. 3:54can get maybe
104. 3:55three to four casts a day and so and
105. 3:58then overnight you might want to let it
106. 3:59dry out
107. 4:00you know just uncovered or put a fan in
108. 4:02front of it or something so
109. 4:04so now that we have a good thickness
110. 4:05here i can kind of see this
111. 4:07um you know the edge here on both of
112. 4:09these now it's time to pour them out
113. 4:11so i have my my slip here my casting
114. 4:13slip
115. 4:14and um what i want to do is i want to
116. 4:16have some two little pieces of wood that
117. 4:18i'm going to put here
118. 4:20you want to make sure that uh you don't
119. 4:22have any drips of the plaster or the um
120. 4:25uh the casting slip from the last time
121. 4:27you did this because you don't want to
122. 4:28have
123. 4:29uh little chunks of dried uh casting
124. 4:31slip fall into your
125. 4:33your nice casting slope that you have
126. 4:34already mixed here and so what you want
127. 4:36to do is kind of space them apart like
128. 4:38that
129. 4:38now when i pour these i'm gonna do
130. 4:40something a little unusual and i'm going
131. 4:41to roll
132. 4:43the mold so that it pours out over the
133. 4:44whole surface here
134. 4:46usually you can just pour it out of one
135. 4:48side but
136. 4:50what i'm with these particular cups i'm
137. 4:52finding that it's working pretty well to
138. 4:54do that because then i'll
139. 4:55i'll take a rubber rib and i'll just
140. 4:56kind of
141. 4:58cut off the top of the of the cup and
142. 5:00i'll do that in the next
143. 5:01video so just keep in mind that you
144. 5:05don't always roll it like i'm going to
145. 5:06do this here but
146. 5:08so generally what you want to do is just
147. 5:09like what happens is when you pour this
148. 5:11out
149. 5:12you know all the wet slip from the
150. 5:13inside pours out and the
151. 5:15the vessel is then kind of stuck to the
152. 5:17side of the
153. 5:19of the plaster so
154. 5:24okay so now i'm going to want to set
155. 5:27this in here
156. 5:29so that it can just drip
157. 5:33and i'm going to leave it um
158. 5:36i'm going to leave it like this for um
159. 5:39you know probably 15-20 minutes even to
160. 5:42make sure everything is dripped out
161. 5:44and then i'll flip it upside down and
162. 5:46i'll show you how to cut off the rest of
163. 5:48it so
164. 5:48so now i have my other one here i also
165. 5:51want to try to get
166. 5:52this loose stuff off the edge here you
167. 5:54know basically you just don't want any
168. 5:55of that stuff falling in there
169. 5:57uh into this lip so here you can kind of
170. 6:00see also
171. 6:01um you know a little bit more defined
172. 6:04here the rim here
173. 6:16okay so now that that's done i'm going
174. 6:19to let that
175. 6:20sit and make sure that all the drips are
176. 6:23out if i take it out too early it'll
177. 6:25flow back down into the foot and it'll
178. 6:27make the foot really thick
179. 6:29also if i take it if i flip it over too
180. 6:31early
181. 6:32i'm going to see drip lines on the
182. 6:34inside of the vessel
183. 6:36so you know right here on this if i flip
184. 6:39the mold over
185. 6:40then it's going to start dripping back
186. 6:41down and i'm going to see these lines
187. 6:43down here and so that's what i don't
188. 6:44want to see
189. 6:45so that's why i'm going to leave it
190. 6:46upside down so long um
191. 6:49because what i'm gonna do is i'm gonna
192. 6:50let those drips almost start to get
193. 6:52leather a little bit leather hard on the
194. 6:54on the bottom here so um so that's it
195. 6:57for pouring it out
196. 6:58and just make sure again just make sure
197. 7:00that your sticks are clean here
198. 7:02um you know and then if you do splash
199. 7:05any up on the edge here
200. 7:07when you take these off that's when i
201. 7:08would clean this out the the side of the
202. 7:10bucket again
203. 7:11so that i don't have any dry um you know
204. 7:14dry
205. 7:14casting slip on the edge of the bucket
206. 7:17so uh that's it for this video and then
207. 7:19when we come back i'll cut the tops off
208. 7:25okay in this video uh i'm gonna um take
209. 7:28the pick these up and i'll show you how
210. 7:29to cut the
211. 7:30tops off of them they've been sitting
212. 7:32there for upside down like this over the
213. 7:34bucket for about 20 minutes
214. 7:36again that's a little longer than is
215. 7:37necessary but i want to make sure that
216. 7:39the
217. 7:40slip doesn't drip back down and also
218. 7:44i wanted to make sure that the top is uh
219. 7:46stiff enough where
220. 7:48i can cut through it with this so um so
221. 7:51what i'm going to do is carefully pick
222. 7:52these up and then you'll see
223. 7:54all of the drips here which i'll i'll
224. 7:57cut off here in a second
225. 7:59and so um pick that one up
226. 8:02set it over here i'm going to take these
227. 8:05up
228. 8:05and set them to the side at this point
229. 8:08i'm going to just
230. 8:09kind of wipe down the inside of the
231. 8:11bucket here
232. 8:12and try to get kind of close to the
233. 8:13surface of the slip
234. 8:16so i make sure that everything is wet
235. 8:18here and i'm not
236. 8:19getting any chunks that are falling in
237. 8:21then i'll
238. 8:24put the lid back on and i'm just going
239. 8:26to kind of roll this over to the side
240. 8:28and um so now i have
241. 8:31um i have these cups here
242. 8:34and what i'm going to do is i'm going to
243. 8:36take this
244. 8:38rubber rib here this is a really
245. 8:40flexible
246. 8:42rib from mud tools the reason why i want
247. 8:45to use this
248. 8:46as opposed to a fettling knife is that
249. 8:48the fettling knife
250. 8:50could damage the the top of the mold and
251. 8:54um and since the top of the mold
252. 8:56dictates that line
253. 8:57it would change the way that the the
254. 9:00finished cup looks
255. 9:02plus it it could dig into the plaster
256. 9:04and chip off little pieces of it then
257. 9:06the chip
258. 9:06plaster gets into um you know into my
259. 9:10cup
260. 9:10so what i'm going to do here is i'm
261. 9:12going to kind of just hold this at an
262. 9:14angle
263. 9:15and i'm just going to cut in like that
264. 9:18and
265. 9:19and just sort of slowly kind of go
266. 9:21around
267. 9:22and you can kind of see what that does
268. 9:26is that it makes a really nice sharp
269. 9:28line there you can also see the
270. 9:30thickness of the vessel
271. 9:31now it's going to be a little bit
272. 9:32thicker right on the rim there
273. 9:34than the rest of it but um but that's a
274. 9:36pretty good thickness here
275. 9:39and so i'm just going to kind of go
276. 9:40around
277. 9:42and clean all this up now i'm going to
278. 9:45um you know eventually i'm going to
279. 9:48clean up the
280. 9:50the rim anyway with a with a soft sponge
281. 9:53um so i don't i'm not too concerned with
282. 9:55these little burrs right here
283. 9:57um mainly just trying to want to you
284. 9:59know i'm trying to get a nice good cut
285. 10:00there
286. 10:01and make sure that i'm not um
287. 10:05you know peeling off the cert the the
288. 10:08object from the
289. 10:09from the mold okay so that's that one
290. 10:13and then uh let's cut this one off
291. 10:22the inside of the cup is still pretty
292. 10:23wet right now so i am trying to be
293. 10:25careful not to drop any of the
294. 10:27little pieces and that's why i'm i'm
295. 10:29taking all the little pieces off over
296. 10:31here
297. 10:32so
298. 10:42okay so so now we have our
299. 10:46our two cups there are a couple little
300. 10:48tiny pinholes so what i'm going to do is
301. 10:50i'm going to just
302. 10:51um take a little tiny bit of slip on the
303. 10:53brush and i'm just going to dab it
304. 10:55on the edge there um and then otherwise
305. 10:59then what i need to do is now i
306. 11:01want to let this sit um you know and
307. 11:04this part really varies depending on how
308. 11:06dry your
309. 11:07your molds are um and what i what i'm
310. 11:10looking for is i
311. 11:11will look for the edge to start to
312. 11:12separate here so that the
313. 11:14cup on the inside is shrinking from the
314. 11:17mold
315. 11:18now this it depends a lot on the mold
316. 11:21how thick it is how dry it is how many
317. 11:23times you cast that day
318. 11:26off the top of my head i'm guessing this
319. 11:27will be about a half an hour to 45
320. 11:29minutes
321. 11:30uh could be longer because this is i've
322. 11:32done several casts on this to this
323. 11:34object today
324. 11:35um but what we'll do is i'll stop the
325. 11:38camera and then we'll come back
326. 11:39when that is separated and we can pull
327. 11:42the
328. 11:43pull the objects out so um main thing
329. 11:45with this part of it is just to make
330. 11:47sure you use something soft
331. 11:49to cut that surface off do not use
332. 11:52anything
333. 11:52hard like a fettling knife because it
334. 11:55will very easily
335. 11:56chip that surface and cut into it so um
336. 12:00i think that's it for this video
337. 12:07okay so now we have our our two molds
338. 12:10here
339. 12:11and um in the last segment i said that i
340. 12:14thought it was going to be about 30 or
341. 12:1545 minutes
342. 12:16and it turned out it was much longer it
343. 12:18was about an hour and a half
344. 12:19now um i did mention that that time
345. 12:23uh you know 30 45 minutes does change
346. 12:26depending on
347. 12:27you know how thick your mold is but also
348. 12:30um
349. 12:30how saturated the mold is so these same
350. 12:33objects were taking 30 to 45 minutes
351. 12:36earlier in the day and now they just
352. 12:37took an hour and a half so
353. 12:39what you're looking for is you're
354. 12:41looking for there to be
355. 12:43separation um all the way around
356. 12:46from the mold and so each of my objects
357. 12:49here
358. 12:50has separation um you know it's starting
359. 12:53to shrink away
360. 12:54and so um that's what you're looking for
361. 12:57the way to do this to take them out is
362. 13:00can be a little challenging you kind of
363. 13:02have to practice a little bit but um you
364. 13:05know
365. 13:06basically what you're going to do is
366. 13:06flip this upside down and you're going
367. 13:08to
368. 13:09put your hand on the inside of the cup
369. 13:11and kind of jiggle it just a little bit
370. 13:13and if it's ready to come out it should
371. 13:15just drop right out
372. 13:16now this is a good example of uh the
373. 13:20importance of not making your mold too
374. 13:22heavy
375. 13:22or it's you know too big um
376. 13:26you know so if i can hold this it's much
377. 13:28easier you know if i can hold this in
378. 13:29one hand it's much easier for me to get
379. 13:31this cup
380. 13:31out so um so i'll try to kind of turn
381. 13:34over here so you can see a little bit
382. 13:35i'm going to put my hand on the inside
383. 13:37and i'm going to kind of just sort of
384. 13:39wiggle this just a little bit and then
385. 13:41really carefully
386. 13:43just pull that cup out and so now you
387. 13:46can see
388. 13:48the um you know these are the lines from
389. 13:50the 3d print
390. 13:52um and so i might smooth those out a
391. 13:54little bit but um i do sort of like the
392. 13:57the quality of those lines now the rim
393. 14:00is um you know it still needs to be
394. 14:03touched up
395. 14:04but when they come out of the mold
396. 14:05they're going to be a little bit too
397. 14:06soft
398. 14:07to handle too much so what i do is i
399. 14:10will fix
400. 14:11something major that's on the rim but i
401. 14:13will let this sit for
402. 14:14you know another 45 minutes to an hour
403. 14:17before i go
404. 14:18around and and clean up the the rim here
405. 14:21and i'll i'll make another
406. 14:22um video a little segment with that so
407. 14:25so now i have that one out let me just
408. 14:27try to take this other one out i'm going
409. 14:28to put my hand in here
410. 14:30and kind of move that and
411. 14:34you can see the inside of the mold is
412. 14:36clean and
413. 14:38you know before i cast the next one i'll
414. 14:39clean up this edge here
415. 14:42but here you can see you know the
416. 14:45the detail in this one you know so
417. 14:48um for now don't worry about this kind
418. 14:50of stuff here
419. 14:51um you know if i tried to clean that up
420. 14:53now i would likely deform this
421. 14:56you can kind of see it's really it's
422. 14:58actually soft enough where it's just
423. 14:59deforming
424. 15:01on its own weight for me holding it so
425. 15:04so they're too wet right now to
426. 15:05to do the final cleanup um but
427. 15:09you know so that was the i guess the
428. 15:11third of the fourth cast from this
429. 15:13object today
430. 15:14i think that's good for today if it's
431. 15:16showing me that it's been
432. 15:17three times as long sitting in the mold
433. 15:20then these molds are saturated and they
434. 15:22really should dry
435. 15:23um overnight so i'll wait to cast those
436. 15:26again tomorrow
437. 15:27so um but again just make sure that you
438. 15:30um see that they're separating from the
439. 15:32edge
440. 15:33if you have to feel like you're pulling
441. 15:35on the cup to get it out of the mold and
442. 15:37it's not ready just
443. 15:38you know if you if you have made your
444. 15:40mold or your object correctly and made
445. 15:42your mold correctly
446. 15:43it should just separate on its own you
447. 15:45shouldn't need to
448. 15:46you know um you know push it or pull it
449. 15:49or anything like that
450. 15:51so just remember that every time you are
451. 15:53doing that you're pulling it or anything
452. 15:55you're
453. 15:55you're um you know changing you know
454. 15:58you're you're likely to damage the
455. 16:00edge or the rim of the cup um and also
456. 16:03remember that porcelain
457. 16:05cast slipcast porcelain has a a really
458. 16:08big
459. 16:08plastic memory so if you kind of move it
460. 16:11and manipulate the
461. 16:12shape of this uh very often when it
462. 16:14fires
463. 16:15it it can it will go back into that
464. 16:18shape so
465. 16:19um so just try to keep it keep the shape
466. 16:21as as
467. 16:22you know as as as as perfect as you can
468. 16:27and that's another reason why i'm gonna
469. 16:28wait until these are a little bit
470. 16:30more stiff to clean the rims up so i
471. 16:32think that's it for this video
472. 16:39okay so um what i'd like to talk to you
473. 16:42about
474. 16:42in this quick video is uh just um a
475. 16:46few pointers about cleaning up the rims
476. 16:48so this is the cast
477. 16:50that came out of this mold here and
478. 16:52there's a few little things that i would
479. 16:54touch up some
480. 16:55imperfections right there but the main
481. 16:57thing is the the rim here so you can
482. 16:59kind of see
483. 17:00you know the rim still has the marks
484. 17:02from when i
485. 17:03cut off the extra casting slip and so
486. 17:06what i'm going to do here is i have a
487. 17:07little thing of water here
488. 17:09i have a natural sponge which is
489. 17:12much smoother and easier to work with
490. 17:15than
491. 17:16than these these will work uh but
492. 17:18they're just a little rougher so they
493. 17:20they do leave a little bit of texture
494. 17:22uh and you can also use a chamois if
495. 17:24you're working on the rim too
496. 17:25so what you want to do is um try to get
497. 17:27this at
498. 17:28uh kind of just shy of leather hard you
499. 17:31know um
500. 17:32just enough where you can kind of hold
501. 17:33it without um you know bending the mo
502. 17:36the the mug or anything and so what i'm
503. 17:38going to do is i'm just going to kind of
504. 17:40go around and work on this on this rim
505. 17:44here
506. 17:44now if you take care when you're pouring
507. 17:47so that's one of the reasons why when
508. 17:48you pour these you want to get it right
509. 17:49up to the edge there
510. 17:51you know if you take care in making sure
511. 17:54that you have a good pour
512. 17:55and that when you pour it out
513. 17:59you know you you're doing a good job in
514. 18:01terms of keeping it clean
515. 18:02then you sometimes you don't have to do
516. 18:04very much here with this you know so
517. 18:06this is a good example of one that
518. 18:07is already pretty good but i just want
519. 18:11to clean up i want to soften those edges
520. 18:13you know if i don't do this those really
521. 18:15sharp edges can
522. 18:17can be extra sharp after the glaze you
523. 18:19know if the glaze kind of splits a
524. 18:21little bit around that rim
525. 18:22you know you want that to be uh soft and
526. 18:26you know not too sharp and so
527. 18:29you know basically you just kind of keep
528. 18:31dipping it in water and then clean up
529. 18:33you know anything any of those little
530. 18:35burrs if you have any little hole
531. 18:37pin holes or anything like that you can
532. 18:39work on that at this point too you can a
533. 18:41lot of times you can just kind of
534. 18:42put a little bit of moisture on your
535. 18:43finger and reach in there and kind of
536. 18:45clean up
537. 18:46you know anything inside that might need
538. 18:48to um
539. 18:50you know any marks or drips or anything
540. 18:52you know you see here there's a little
541. 18:53bit of a drip so
542. 18:55you know i could just put a little bit
543. 18:56of moisture on that the casting slip is
544. 18:58actually pretty forgiving so you can
545. 19:01uh you know just just a little bit of
546. 19:03water uh really
547. 19:05rehydrates it pretty well and then i can
548. 19:08if i want to i can come back
549. 19:10here with this really soft chamois and
550. 19:12um
551. 19:13you know just kind of run it around a
552. 19:14few times and that'll give it a really
553. 19:17nice sort of
554. 19:18rounded almost like a thrown rim kind of
555. 19:21look here um so
556. 19:25so that's what you want to do you'll do
557. 19:27the same to the bottom if you have any
558. 19:28any uh marks or anything that you want
559. 19:30to clean up on the bottom
560. 19:33and then you know once you do that then
561. 19:35you're ready just to let it dry
562. 19:38you know just let it dry out in the open
563. 19:40too you don't need to
564. 19:41put it in the damp box or anything like
565. 19:43that so
566. 19:45so that's it for cleaning and fine
567. 19:47tuning
568. 19:48your cup from your one part plaster mold