I am finally able to make the molds for the fuselage. The heat was preventing the rubber from curing properly-- it was curing too quickly and not flowing through the jacket. Actually, I should say the problem was discovered on a different project, thus these molds were never done until now.
I have documented the process of making these molds using my still camera. I started using my DV camera, but the resulting video would have been way too long. And this way, everyone can view the process without having to fuss with the video! All that will be missing will be my witty banter and bad lighting. There are a LOT of photos in here, so this will take a while to load. I've used high resolution photos in case anyone wants to download them for later study.
The first half of this process is documented here and I will be adding the rest as I get to it, in the next couple of days. This will take you from mounting the model to pouring the first half of the jacket.
The pattern is mounted to the smaller block with a screw from the underside. This block represents the space where the flange of the mold core fits-- don't worry about that now. This block is mounted to a 'background' plate, used in place of just using the table. The right-hand image shows the start of the parting board. A line is traced around the master and that area will be removed.
On the left, you can see that the master has been covered by plastic wrap. This will keep the clay from sticking. On the right, the parting board has been cut out and mounted to the base.
As you can see here, supports have been added to the back side of the parting board, allowing the master to sit level. Also, walls have been constructed to contain the resin when it is poured. A wax release agent has also been brushed over the parting board, walls and base so that the jacket won't stick. Any gap between the master and the parting board can be ignored as it will be covered with the clay.
This and the following 3 photos show how the clay is cut to the proper thickness for this project. Since the clay represents the volume of rubber that will make up the mold, it defines how thick or thin the rubber will be when the mold is finished. In this case, we need the rubber to be about 1/2 an inch thick. String is used to cut the clay. Starting on the back of the block, the string is pulled slightly into the far corners, seating it. The free ends of the string are then brought to the front and exchanged from one hand to the other.
When they are pulled taught, the string bites into the clay--
--and continued tension will draw the string through the body of the clay, cleaving a slice cleanly--
--as seen in this final shot of the sequence. I should also add here that this is not ordinary ceramic or pottery clay. This is called WED clay. It contains lanolin so that it won't dry out as quickly as regular clay. And, yes-- that is WED, as in Walter E. Disney.
Covering the master with the clay.
Edges are trimmed straight. This makes it easier to mate subsequent pieces of clay.
Pieces should fit as closely as possible.
Once the master is covered, the seams have to be blended and the whole thing has to be smoothed out.
The 'cocoon' is spritzed with water to wet it down and smoothed over using a piece of clay.
A rim and rib are added so the final mold will register properly to the jacket.
The jacket can be made using a variety of materials. Some people use plaster, some use fiberglass. I use a filled resin and cheesecloth. The cheesecloth is laid over the cocoon. The first batch of resin is poured and brushed into the cheesecloth using care to get all the bubbles out.
This photo was taken after the second (and final) coat of resin and cheesecloth was done. Note how the small block at the base of the pattern has been covered.
This is only the first half of the jacket. I'll finish it tomorrow and post the rest of this coverage in the next day or so. Getting to this point took most of the day today!
I have documented the process of making these molds using my still camera. I started using my DV camera, but the resulting video would have been way too long. And this way, everyone can view the process without having to fuss with the video! All that will be missing will be my witty banter and bad lighting. There are a LOT of photos in here, so this will take a while to load. I've used high resolution photos in case anyone wants to download them for later study.
The first half of this process is documented here and I will be adding the rest as I get to it, in the next couple of days. This will take you from mounting the model to pouring the first half of the jacket.
The pattern is mounted to the smaller block with a screw from the underside. This block represents the space where the flange of the mold core fits-- don't worry about that now. This block is mounted to a 'background' plate, used in place of just using the table. The right-hand image shows the start of the parting board. A line is traced around the master and that area will be removed.
On the left, you can see that the master has been covered by plastic wrap. This will keep the clay from sticking. On the right, the parting board has been cut out and mounted to the base.
As you can see here, supports have been added to the back side of the parting board, allowing the master to sit level. Also, walls have been constructed to contain the resin when it is poured. A wax release agent has also been brushed over the parting board, walls and base so that the jacket won't stick. Any gap between the master and the parting board can be ignored as it will be covered with the clay.
This and the following 3 photos show how the clay is cut to the proper thickness for this project. Since the clay represents the volume of rubber that will make up the mold, it defines how thick or thin the rubber will be when the mold is finished. In this case, we need the rubber to be about 1/2 an inch thick. String is used to cut the clay. Starting on the back of the block, the string is pulled slightly into the far corners, seating it. The free ends of the string are then brought to the front and exchanged from one hand to the other.
When they are pulled taught, the string bites into the clay--
--and continued tension will draw the string through the body of the clay, cleaving a slice cleanly--
--as seen in this final shot of the sequence. I should also add here that this is not ordinary ceramic or pottery clay. This is called WED clay. It contains lanolin so that it won't dry out as quickly as regular clay. And, yes-- that is WED, as in Walter E. Disney.
Covering the master with the clay.
Edges are trimmed straight. This makes it easier to mate subsequent pieces of clay.
Pieces should fit as closely as possible.
Once the master is covered, the seams have to be blended and the whole thing has to be smoothed out.
The 'cocoon' is spritzed with water to wet it down and smoothed over using a piece of clay.
A rim and rib are added so the final mold will register properly to the jacket.
The jacket can be made using a variety of materials. Some people use plaster, some use fiberglass. I use a filled resin and cheesecloth. The cheesecloth is laid over the cocoon. The first batch of resin is poured and brushed into the cheesecloth using care to get all the bubbles out.
This photo was taken after the second (and final) coat of resin and cheesecloth was done. Note how the small block at the base of the pattern has been covered.
This is only the first half of the jacket. I'll finish it tomorrow and post the rest of this coverage in the next day or so. Getting to this point took most of the day today!
