#molding shrinkage

[gudmould]

Introduction to plastic classification and molding process

Plastics and Molding Process2.2 Processing properties of plastics I. Processing performance of thermoplastics 1. Shrinkage After plastic part is taken out of mold and cooled to room temperature, dimensions of each part of plastic part are smaller than original dimensions in mold. This property is called shrinkage.Forms of molding shrinkage(1) Linear dimensional shrinkage of plastic parts(2)…

[blueiscoool]

1,500-Year-Old Christian Ivory Reliquary Box Discovered in Austria

Archaeologists have discovered an exceptional Christian ancient ivory reliquary box in Austria that is thought to be around 1,500 years old.

Innsbruck archaeologists have been excavating in an old hilltop settlement in southern Austria since the summer of 2016. They made the incredible discovery of a Christian reliquary concealed in a previously unknown church two years ago. This reliquary contained an ancient ivory box, richly decorated with Christian symbols.

The incredible artifact was discovered on August 4, 2022, in an early Christian church on the Burgbichl hill in Irschen, southern Austria, by a team headed by archaeologist Gerald Grabherr. A marble shrine measuring around 20 by 30 centimeters was hidden under the altar in the side chapel area.

The artifact in question is heavily fragmented, but researchers said the pieces once formed a type of round container known as a “pyx” that in this case was made of ivory and richly decorated with Christian motifs.

The shrine contained a heavily fragmented ivory “box” (pyx) richly decorated with Christian motifs – a reliquary that is normally taken away as the “holiest” part when a church is abandoned. In this case, however, it was left behind. It is the first such pyx to be found in an archaeological context in Austria.

“We know of around 40 ivory boxes of this kind worldwide and, as far as I know, the last time one of these was found during excavations was around 100 years ago – the few pyxes that exist are either preserved in cathedral treasures or exhibited in museums,” explains the finder, Gerald Grabherr.

While the archaeologists initially assumed that the remains of a saint – i.e. a relic in the classic sense of the word – were also found in the marble box, the layering of the fragments found in the shrine indicates that the ivory pyx was already broken in late antiquity and was buried in the altar.

“The pyx was presumably also seen as sacred and was treated as such because it was in contact with a relic. The archaeological and art-historical significance of the pyx cannot be denied,” emphasizes Gerald Grabherr.

At one end, the pyx shows a figure at the foot of a mountain – the man depicted is turning his gaze away and a hand rising out of the sky above him, placing something between the person’s arms.

“This is the typical depiction of the handing over of the laws to Moses on Mount Sinai, the beginning of the covenant between God and man from the Old Testament,” says Gerald Grabherr. This is followed by depictions of biblical figures. At the end, you can see a man on a chariot with two horses harnessed to it – and here, too, a hand coming out of the clouds pulls this figure up into heaven. “We assume that this is a depiction of the ascension of Christ, the fulfilment of the covenant with God. The depiction of scenes from the Old Testament and their connection with scenes from the New Testament New Testament is typical of late antiquity and thus fits in with our pyx; however, the depiction of the Ascension of Christ with a so-called biga, a two-horse chariot, is very special and previously unknown.”

Since its discovery, the 1,500-year-old ivory pyx has been conserved at the University of Innsbruck.

Ivory stored underground absorbs moisture, making it very soft and easily damaged. Uncontrolled drying can lead to shrinkage and cracks.

Ulrike Töchterle, head of the restoration workshop in Innsbruck, said, “The high humidity in the marble shrine meant there was a high risk of condensation and mold, so we had to ensure a careful and prolonged drying process.”

Over the past two years, the individual pieces of the ivory pyx have been conserved for scientific analysis. The larger parts are deformed, so the pyx cannot be restored to its original state. However, researchers are working on a 3D reconstruction.

By Oguz Buyukyildirim.

[holyscreamingintothevoid]

Still working on my Frank pin. 💚 I’m doing gravity pewter casting in a silicone mold and as you can see, even after a double-digit number of attempts I still haven’t figured out the correct amount of pewter to pour while also trying to account for the shrinkage happening in the middle. Tremor is not helping either (lol) but it’s going a lot better than I expected!

Pin design is based on nostalgebraist-autoresponder’s avatar, which is itself an edited version of the painting Horse in Analogous Color Scheme by doni19.

[0m3g4skanohiforge]

Just realized I hit a proper milestone a while back and never celebrated - a successful version of what my very first attempt was, a Red Komau

The first attempt was messy. Filled with tiny bubbles, a big hole in the forehead, mouth lacking definition, soft, and transparent/inaccurate colour. It hardly fits in the mouth properly, the original mold did not get those precise shapes accurately. Nowadays, while my Komau mold isn't 100% perfect and current resin has ever-so-slight shrinkage, I've got a good match for Red and the shape is near-indistinguishable without careful examination or tools.

As with any art form, it's easy to see others doing it and think it must be easy. But by far, the most important thing is dedication and perseverance. (Second most important is safety!) I wanna thank everyone in this community for all their kind words while I developed the skills and experience needed to produce casts like this.

[anonymusbosch]

it's cool to have my parts come in and test them out and see the phenomena from my injection molding textbook play out in front of me. look at that! it breaks right at that stress concentration! or when overloaded here, it breaks right at the weld line! there's shrinkage here and here! even stuff like anisotropic strength due to the orientation of the glass fibers and the polymer strands is right there in front of my eyes. yes!! yes!!

[cneasteel]

When Is The Investment Casting Employed?

A wax pattern is used in the industrial process of Investment casting China, sometimes referred to as precision casting or lost-wax casting, to create a disposable ceramic mold. The exact shape of the object to be cast is captured in a wax pattern. A ceramic substance that is refractory is applied to this design. After the ceramic material solidifies, it is heated and flipped upside down until the wax melts and runs out. The ceramic shell hardens into a disposable investment mold. The mold is filled with molten metal, which is then allowed to cool. After that, the metal casting is broken out of the used mold.

When to employ investment casting

Investment casting is a rather expensive technique because of its labor needs and intricacy, but the advantages frequently exceed the drawbacks. Almost any metal may be cast for an investment. 

Excellent as-cast surface finishes may be achieved in complicated items produced by investment casting. Since the ceramic shells of investment castings break away from the part when it cools, a taper does not need to be incorporated to extract the components from their molds. With the use of this manufacturing feature, castings with 90-degree angles may be created without any shrinkage allowance and without the need for further machining to achieve such angles.

Parts made using the investment casting technique by Investment casting Supplier have excellent dimensional precision, are readily net-shaped, and are frequently produced without the need for further machining. To create wax patterns, a new die is needed for every distinct casting run. 

The time and effort saved by reducing or eliminating secondary machining more than offsets the expense of new tools for high-volume orders. Lesser casting runs will probably not pay for itself. 

A new wax pattern to a finished casting typically takes seven days, most of which is spent making and curing the ceramic shell mold. To make castings more rapid, certain foundries can quick-dry. Cost is not the only factor affected by investment casting's time- and labor-intensive process. Longer lead times for the investment casting process are typical at foundries because of their restricted production capacity and equipment.

More Information: Mastering the Art of Investment Casting: A Deep Dive into the Process

[k00242882]

Making clay handles for a saw.

*I wanted to make ceramic handles for a saw that has been hanging on the wall at the back of my house for years now.

*I took the idea from Artist Richard Slee who did a full exhibition on Futile Utilities.

The tricky part of this is making the handles that can fit on over the saw and look like it's part of it.

I got a lot of help from Elaine, with ideas and teaching how to actually cut a straight edge in clay, how to hold a knife and score, score then cut.

I hope that with the shrinkage in the kiln, the handles will fit🤞

I also did some porcelain clay on my ready made mold.

It was a bit sticky taking it off so Elaine guided me, once again through the process, trying two different types of porcelain paper clay

[faux-phallus]

Safe Sex Toy Materials

Why Silicone…

There are a lot of things that go into making a quality product. 

But first and foremost it starts with quality ingredients/materials. That is why we at Faux Phallus will only ever use bodysafe Platinum Cured Silicone and we'll explain why...

Unfortunately the industry to date is still unregulated. This is never more apparent than in the case of adult toys. Not worried yet? You should be, as long as sex toys are labeled as 'novelty items' big corporate companies can get around using questionable materials.

There are a long list of materials in sex toys that are a cause for medical and safety concern, even if your favorite toys are made of materials known to be safe. Some of these products can contain chemicals or oils that soften the material to make them more pliable.

There are still sex toys being produced that contain phthalates even though these have been known for years to cause issues, but phthalates aren’t the only harmful chemical being used. 

There are sex toy materials that have never been proven toxic yet are still softened with oil (grades and types unknown), these materials can still break down and become unstable, and can still be porous enough to harbor bacteria, mold and transmittable viruses. 

Even if the material is non-toxic when you first buy it, that may change over time as the material breaks down. Chemical changes can occur, oils can be released along with new odors, and more. 

If your toy is not made of the materials listed below, then it can be potentially unsafe or downright toxic. Although some people may not notice any issue with using them, the larger majority can notice burning, stinging or other medical issues.

The list of the safest materials for adult toys would be...

Silicone Toys These come in two categories that refer to the curing agents used. they are either...

Platinum Cured Silicone “compatible for skin contact”

Tin Cured Silicone “is not compliant with food or skin”

If a company tries to call their silicone a “Blend or Mix”, be very cautious and ask yourself what its blended with?

Some of the other benefits of silicone are that it's allergy-friendly, nonporous, hydrophobic, phthalate free, durable, easy to clean and sterilize. It's odorless and doesn't suffer from shrinkage.

I myself have bought toys in the past that have shrunk in size (I'm talking inches in length and girth have been lost) when you buy a 9" toy and a couple of years down the track it is 7½" you know its deteriorating.

Wooden Toys can be very safe, if the finish is medical grade. 

Stainless Steel Toys as long as they are medical grade stainless they're very safe. 

Austenitic 304 and 316 stainless steels are considered surgical or medical-grade stainless steels

Glass Toys as a material is safe, but be aware of cheap brands that don't anneal, annealing is a long process that makes the glass extremely tough. Un-annealed glass won’t be overly fragile, but it needs to be handled with care. Cheaper brands may also paint glass which needs to be avoided unless you can verify the paint is safe.

Ceramic Toys are safe, so long as they are glazed and kiln-fired. The glaze keeps the toy non-porous. Although it is worth noting if the surface has a crack it can be porous and harbor bacteria so care needs to be taken with use and storage.

Out of all these materials silicone is the only one that is flexible, making inserting into the body the most comfortable experience, but by all means the other materials have their place in the industry. It'll all come down to your personal preference.

Casting…

It is defiantly worth noting... Silicone is a 2-part mix that needs to be well combined, after mixing a lot of air bubbles are trapped within the viscous material. To this end a reputable toy maker will use a vacuum chamber to draw all the air out of the silicone before it is poured into their respective molds.

In days past some makers would cure their silicone in a pressure pot, under 60psi of pressure to make these bubbles shrink down in size. Some have and still do unfortunately, let their toys cure without either of these precautions. But without these basic procedures, these air bubble pockets are somewhere bacteria and mold can be trapped and grow.

It’s worth doing your research to make sure your toy has been degassed. 

[thegeekyartist]

Got my mugs back from that class I took!!

They're all lumpy bumpy because I molded them to my fingers and I'm thrilled to report that it worked! (I had to account for clay shrinkage in the kiln).

That brown was unfortunately supposed to be blue but otherwise I love them 😭💖

[the-bjd-community-confess]

A bit of info for collectors: sometimes when companies/artists refuse to re-release an old model it’s not because they don’t want to, but because they just can’t. Molds have a set amount of casts they can produce and if the master head is lost, all they could do is recast one of their own heads, which leads to a new set of issues including but not limited to shrinkage and loss of detail. It may be also that they just want to move forward to different sculpts.

~Anonymous

[marsbookstore]

Well my pressure pot works!

It's outputting some nice bubble free dice

I gotta make new molds though. I didn't cure my molds in the pressure pot and so i got all these little beads on the surface and the wells for shrinkage weren't big enough

I'm so close to being able to make dice good enough to sell though!

[gudmould]

What are factors that affect plastic shrinkage?

(1) Influence of raw materials Plastic Shrinkage OverviewShrinkage rate of plastic refers to percentage difference between size of plastic part at molding temperature and size after it is removed from mold and cooled to room temperature. It reflects degree of size reduction of plastic parts after they are removed from mold and cooled. Factors that affect shrinkage rate of plastics include…

[tache-noire]

am i the only one who's like. really bothered by the popularity of resin crafts in the past few years.

Like, I've seen maybe one person on youtube EVER address the fact that Absolutely Anything You Make With Resin Will Turn Yellow In 2 Years (And Probably Crack).

It depends on the type of resin, how fast it goes and how yellow it gets, but ALL resin will turn eventually. Like, there's a reason why most snowglobes are made from glass or injection-molded plastic! There's a reason why the tried-and-true pre-DIY processes for producing these things ARE tried-and-true. Because they LAST. Resin just doesn't. Within a few years, your snowglobe or shaker charm will be yellow and it may even crack and leak.

What bothers me the most about resin crafting is the people "preserving" things in it. People starting businesses preserving keepsakes in resin.

It breaks my heart to know that people are handing off their wedding bouquets to be coated in resin, thinking they'll be beautiful forever. But then in a couple years, it'll be ugly and yellow. Nobody tells them this.

I literally have 2 bottles on my desk of resin base and hardener that I bought in 2020, with the intent of using it to make a costume piece (I never did.) The hardener is piss-yellow now and appears to have shrunk somehow (the bottle is dented as if there's negative pressure inside). That will happen to anything you make with it. And that shrinkage will cause cracks and weaken connections if you've used it to glue pieces together.

[pbandjesse]

Happy new year!! I am so glad you are here in this new year to read this post.

Last night me and James wore matching jammies and laughed and watched tiktoks until right before midnight. I found a live stream for us to watch. James had put together our first footing basket. This was the first time I let James do the whole thing. I was sad that there was not CNN drunk anchors this year but we had a good countdown. James was in the hall. We had our shoes on. And at midnight I was holding Sweetp. I kissed James's. I kissed Sweetp. James kissed Sweetp. And we got ready to go to bed. Happy new year to us.

I slept really well. James left for work a lot earlier then me. And when no I woke up they had made biscuits. Excellent news. I got washed and dressed and felt really cute and good. I packed up my temp blanket and headed out. It was very warm today. Way to warm for January first. I didn't even wear a jacket today.

I drove to the museum. And was there a little early. I was happy to see James.

I Wisconsin lottery today just working on sewing down the edges and weaving in the ends of my temperature blanket. And it just felt so nice to be able to lay it out on the big table and look at it and see everything that I worked on. There are some funny spots. There's a fold in the middle where the loom wraps around. And a couple spots that are a little wonky but nothing is a huge deal and I think over time it'll settle. And I was just having a great time working on that.

After about an hour James came and found me because someone wanted a tour. I didn't have my phone on me because the stress doesn't have any pockets so I didn't get their text. But they came and got me and we called for the tour and it was a lovely family.

I wasn't sure they were really enjoying the tour though because they made no sounds or facial expressions the entire hour. At the end of the garment loft portion the mom told me that she owns a mill where they make yarn out of alpaca wool. But that was the most they said the entire time. It was really cool to learn that though good to know that a mill is around.

But apparently they really enjoyed it because afterwards like an hour later, the dad came and found me and he was all smiles and told me how much he loved the tour and thoroughly enjoyed himself and has decided that this is his new favorite museum and because I spent so long with them he gave me $20. I could have cried he was so sweet. I hope he knows how important that was to me because it wasn't about the money. It was definitely about how much his like actual heartfelt thanks was. It was great.

And really all the conversations I had today were wonderful. At the end of my first tour, my only tour, there were three guys that had wandered into the exhibit. And I told them if they had any questions to please let me know as well. I knew that they were there just because of Beth steel exhibit because James had told me. And they were like oh yeah that's what we're here for and I said have you seen the machine shop yet. And they didn't so I was like well let's go check it out and they were so jazzed. I ended up spending almost an hour with them not even doing a tour just talking. They were three guys from the south and it was a guy a little older than me his dad and his grandfather maybe. I'm not really sure who the third man was but they all were so nice and they had very fun accents. And they had lots of really good stories. They knew a lot about steel work and because I love bringing this up, I talked about my bronze casting past and all of the welding I know how to do. It always gives me cred with guys like this. And the youngest guy was just like oh my god you're married You're an amazing woman What a catch. And it was very funny and we talked about shrinkage and how you make sand casted molds and the different properties of patina. And it just felt really good. We also talked about coal towns and their family's history with that and how people got script and company coins. And I had a lovely time talking to them. I took them over to see the car because the oldest guy said that he was really an antique car building and didn't even know we had the 53 clipper. And eventually I did have to leave them because James was texting me about a lunch break. But they were so sweet and I really enjoyed every conversation I had with people today.

James went to 7-Eleven and I stayed at the desk. And when they got back I went back to the garment loft to finish my stitches. It was getting a little bit later in the day. Sundays are quiet for me and short. But I finished the last of my weaving and I just felt so excited. Two women came in and I got to talk to them about my blanket and they made jokes about saying how well I guess they went to an art museum today. And they had all kinds of questions. And I was just feeling really good.

We finished up the day and I hung out at the desk with James while they finished up everything they needed to do. And then it was time to go. As we were leaving a few women came to the door from the sailing center and they set out loud and wonder if the museum had even been open today. And I opened the door and I said we had been but we just closed. And they said oh that's a shame but can we please use the bathroom. And James, out of the goodness of their heart, let them go use the bathroom while we set up a shot to take a picture and video of my finished blanket.

The way that I had originally wanted to do it was me standing on the bench but the way that the sun was there was no good way to do it. So we ended up just doing it on the stairs and I'm surprised no one has yelled at me yet about getting the blanket on the ground but I don't care so it's fine. And I just felt so happy.

We said goodbye to the ladies and lock the door. James put the alarm on and we went home.

When we got back here James insisted on carrying the blanket inside because they want to practice putting weight on their arm. I am afraid they're going to hurt themselves. I think they're trying to do too much too soon. But I'm trusting them. And they would hang out for a while because they were going to go to football game tonight with their family.

I laid in bed for a little while. James made me a quesadilla because they love me. And after I ate I went to go work at my desk and that is where I spend the next 4 hours. With one small break to take a bath. The bath was great but now my back is on fire.

And while I have been having the best time because I'm making, I am in pain!! I have complained before that my arms and back ache after multi hour art sessions. And my doctor's just tell me, gently, that I shouldn't do that. But I have to do it??

Today was a good making day. I feel kind of low because of money. I hate thinking about money. I just want to work and be able to live comfortably and buy nonsense sometimes. But money is on my mind. I am doing a no buy month. Best I can. I made rules and everything. But one of the ways that I think I will be able to accomplish this is by really throwing myself into making stuff with the materials I already have.

And so I've been working on squares. I think this is going to be another blanket, maybe a gift for someone, but I'm making it just of all the leftover yarn I have in the weight that I used for my temperature blanket. And so far it's going great. I made a number of squares yesterday and today I may even more. I think I have 18 squares now? I'll have to count again but I'm really excited. I'm not great at crochet mostly because I have trouble holding numbers in my head. And I get very confused by that. But I am attempting to make them approximately 11 rows across but they're all around the same size at least.

And I finally stopped working and went to go eat some leftovers. And now me and sweep here hang out in bed. James is still at the football game and will be home probably by midnight if not later. But that's okay. I hope they are having fun with their family. And I'm having a nice time here alone. It's nice to be on my own sometimes.

Tomorrow I go to the doctor where I hopefully will get my first injection of my new medication. I'm still not sure how much the copay is and that makes me very worried that no one has talked to me about that yet. But it will be a good day either way. I hope you all have a really good night. And here's to a happy new year.

[ariaste]

Ok since i saw this yesterday I have grown fascinated and gone on a deep dive. First of all, Kim Beaton invented that concrete-and-rubber-fibers stuff she mentions. It is called Pal Tiya Premium, and there is a whole youtube channel with all the information about how to mix it and use it. https://www.youtube.com/@PalTiya She makes a giant sculpture of The Great A'Tuin and Discworld with it!!!

Secondly, it cures in air alone, no oven or kiln required, and unlike clay it has microscopic shrinkage between wet and dry, so you can pack it around glass or whatever. When she says you can stand on this stuff, yes, you can (though for very large sculptures or very narrow sections of a sculpture, she recommends adding a metal armature for extra strength). It is impervious to water, so it can go outside in any weather, and any metal armature encased inside it won't rust

Additionally, Pal Tiya Premium can be added to at any point in the curing process, even weeks or months later, so you can make a sculpture in several pieces and, like with a mold, remove the foil core you sculpted on so you can use it again and again (though you have to add a sacrificial layer of foil between the core foil-sculpture and the Pal Tiya (see the videos on the youtube channel about it). You can color it with oxides, concrete stain, inks, or acrylics, including exterior-grade house paint so your sculptures can go outside.

Holy crap. My only question now is what am I going to make with this stuff, what do i need to have in my garden, aaaaaaa

[k00242882]

The ups and downs of ceramics and glazing.

I made the plate with the mold yesterday.

I left it overnight on the mold.

When the clay starts to dry, it shrinks and because it was on the mold it had no room for shrinkage so it broke

Lesson learned.

I'm determined to get this process down.

Mary gave me a great lesson today .

Every part of the process is very important.

From rolling out the clay, to handling it.

Placing it on the mold with the cotton

Leaving the cotton on top while smoothing it out with the plastic kidney

Cutting the edges with a harp.

Letting the banding wheel do the work while you keep your hand, arm and elbow static.