Today, I'm going to show you how
make a two-part mold from a glass bottle.
The first thing to do is to find and mark the line of
division, and when you look at a a product that is in glass, often the
division line is marked. Then, we just have to take our felt pencil and come and mark it all the way around. Once that's done, have the setting in scope put in reach. We use a small clay cake, and then we'll sit down
our model on. We will take our square. What is important is to
to put our prototype squarely to avoid undercuts. Then, after that, our dividing line.
Here, I plugged the bottom of the bottle with plaster. Because our
video is to make a mold of parts, more later there will be one in 3 parts.
Then, what is important here is to use a level, then put our
line really at the level of our dividing line must be at the level. Once that's done, Once that is done, we check again with our square, then my bottle is installed on a small clod of clay.
She is at the square, then my division line here is really at the level.
So, I continue to put clay around my bottle. I put clay up to my dividing line. I will finalize with a wooden tool to really put it just at the right height, and I put a slight slope in
at the bottom of the dividing line. You will understand why later. I went to the stopper any bottle
it takes a casting hole. For my mold, I shot a
plaster cap, but for those who have no plaster tower they can
use a funnel. A shape asymmetric, then it'll do
the opening for the mold chimney. I'm going to use my cap, so I put on my cap. I check
so that it is right at the square that my line of division arrives opposite that of the bottle, so I have to put some clay here because my plaster cap goes inside the bottle, and it creates an undercut. So, to remedy that I take clay, and I really come to plug the undercut with clay. Now, my setting-in-scope is made,
so for the dimensions of the mold, I recommend 1 inch of plaster of the
part of the widest part. Then, I make a mark at 1 inch
on each side, 1 inch for the bottom, also. I use my square to trace
the size of my mold. I will mark on clay with a sharp tool. I do the same thing on the other side. On the side of my fireplace, I put my
square on the chimney, then I just come trace to my side, so I just have to remove the excess clay. It is always better to cut the clay downhill like this to be sure that our board adheres well. Do you see, there? I created a small void here. It's wanted here because when I'm going to put my veneer board, she'll be sitting on the clay. Once the operation is over.
Glass, it is not obligatory to soap, but I have a plaster cap, so I'm just going to give it a little bit of soap to make sure it does not stick. And the plaster I had put on my back. Now for my boards, I
am going to measure my square. I have 12 inches length, so 12 inches in length
we must always add the thickness of the plywood which is 3/4 inch, so that's going to give me planks of 12 inches and 3/4 each.
I have 5 and 3/4, 6 1/2. Do you see? 6 1/2 there. My board goes over a little bit. My other board will go here, then I'll go around like this, so I have my boards. As you see, it goes a little bit and it's normal like that. I do the same thing here, so I put my boards all the way around
my clay. I take a strap I put a belt to secure the boards, and I'm going to install my boards to the square. and as you can see my clay he
there is a little gap between the clay and my box. Clay. I just just pressed
clay along the wall to avoid leaks, and the trick is played well here. And the thickness of my mold is always an inch, so I use a square, and I just make my mark to an inch. For the preparation of the plaster
in quantities we can weigh our water. If we have 10 pounds of water and multiply by 1.5 for the amount of
plaster or put the plaster to the water in the container it's okay. After about three minutes of mixing
my plaster is ready to pour. Important to properly equalize. After a dozen minutes, my plaster
is solid, then it's time to remove my box.
That's why I take off a strap, but before removing my two belts, I will put elastics. Because of the way I do my
boxes, we do not have to undo our box. We just take off
the planks of the molds then it's extensible boxes. We give small blows to the ends like that and that's it. We just have to clean it, then there. We equalize our mold because in the boards there are always imperfections It makes. You just make it a little bit Smooth. There was a little leak here. It is unimportant. These are things that happen frequently. Then, I use a plane to make my chamfers. I still work my plaster before it heats up. I do the work that's on it, then there. Before unmolding my pieces or
take out my glass pieces, I'm going to wait for it to heat up so that everything is done. Here I go. In about five minutes, my plaster will heat up, so I'm going to turn it upside down, remove my clay and then work my mold. so my plaster has hardened a bit so that I return my mold, and I'm going to remove my clay.
I'll leave, I'll wait a little bit that my plaster heats before unmolding. I will use a truscan to mark
my line division all round the mold. As I had mentioned to you earlier, I slightly put my clay on a slope a little bit lower than my line of
division. So, by flowing my plaster well it allows me to remove the excess plaster. So, I make a mark on my
plug to be sure to put it back exactly in the same place, and I'm going to unmold. And here I have to plane my mold,
the plane I use also. We did that. I also use one called an over-shape or a finishing plane, and it's important to remove the plaster to the dividing line. After that, I use a scraper to make a
finish before sanding. After that I use a soft sand paper,
Sandpaper number 220. Good my sanding is
almost finished, then I will mark where I'm going to do my keys. Then, I
go make one here, one there, two here and one here. Very important to thoroughly clean
our mold before replacing the model
prototype inside. Then, we will put our cap. So, the soap, the plaster has never been soaped. Must give at least 3 layers of soap on the mold part. Good. Here is my third layer of soap, and after that, I'll prepare my plaster,
then do exactly the same thing as I did for the first part. Good, my
third layer is complete. Then, as for the first part being
given that my cap comes in to inside the bottle,
it's a little against that's what I'm going to put back clay as I did at my first casting to remove the
undercut, then I finished putting my clay to remove the undercut. I'm going to get ready, I'm going to put my box, that is to say before I measure all around the thickness of my mold. For
my second such part, I have 68 millimeters. The advantage of having boxes that you do not have to undo every time. 68 millimeters. Here I always put a strap
to make sure my box does not open. So, I have to prepare the plaster, then I will cut my second mold part. Well, my plaster is mixed about 3 minutes, so always equalize. About 10 minutes later, my cast is solid enough
that I am able to remove my box. then, I take off my belt I take off my plywood from the mold and that's it. I do the same operations. only for the first casting,
I smooth. I will use my planer to make chamfers because, once dry, plaster left sharp like that, it's quite
brittle. So, all you have to do is wait a few
minutes until my plaster heats to unmold my second part, and
the initial mold will be finished. I will have sanding to do inside the mold, then after that, I'm going to make mother mold. That mold I'm going to show you how to make a mother mold. Good. The final touch: Given
that I am a person who likes to do things well, I take a big sand paper, and I'm really going to smooth the 2 parts. Good. Ten minutes were
elapsed, then I'm ready for the release. My plaster heats. Here is a part. You see my keys that I dug just now. I take off my cap. There you go. This is the initial mold of this
bottle I still have some finishing to do, and then I will show you how to make
the mother mold. At this time, I still have some finishing. Well, I trim the end of the keys, because when we make a production by casting often small pieces of clay can enter or other things in that,
and then creating a small gap.
Well, we are sure that our mold will always close well. I use sandpaper, number 220, there I go. I just come sand around, or if I see a little
defect, I will remove it. Here, I have a kind of little ridge that I'm just going to go through with a small scraper. There. The same thing here. Here, we see that there is a small infiltration of soap. That is not so important because we do not have to clean it. Right now, I'm going to make a mother mold, and I'm going to soap.
Completed. Our initial mold finished. We begin the stage of making
a mother mold. A mother mold is used to make production molds,
make some molds in series. So that's what we must make. First, always soap.
I will use 3 coats of soap for my box. Redo another box, and here I go
to cast a plaster that is different from "Pottery Plaster"
it's called "Ultracal 30." It's a kind of gypsum. It's hard
like cement. So, I will start my soaping. Okay, finished. Then I will use the same steos that I took to do my
initial mold then, I have my boards for making the second box like I
have already explained to you. The length of my mold plus the thickness of my
board to make boxes removable. For the thickness of the mother mold, I would go about 1 3/4 inches. It's enough. So here, I am going to prepare my plaster, so I'm using Ultracal 30 to make the mother mold. And the quantities are the amount of water multiplied by 2.6 for the Ultracal 30 versus 1.5 for Potery Plaster.
It's a plaster that is really very very hard Good I mixed my Ultracal 30 about 8 minutes. It is ready to pour in my initial mold. As you can see, the color is different. Always think of levelling. Good my Ultracal 30 plaster is on the line. To be ready, watch the water get absorbed. In five minutes, I'll be able to
to remove my boxes and then smooth the mother mold ten minutes later.
My Ultracal 30 is ready. I will remove my boxes, and I'm doing exactly
as with my initial mold. I smooth the sides of my mother mold. After my initial. Well, my Ultracal 30 is very hot. It has hardened, so the time has come to take off the 2 parts. it often happens that pieces, pieces of the initial mold remain stuck or breaks but because Ultracal 30 does not matter
there is no problem for that, do you see? because you have to massage when even strong enough. We will do the same thing on this one There you go! the mother molds. So, to make production molds: light sanding, remove imperfections, always
soap, put back our boxes, prepare our plaster and make our production molds.
