Making a Hollow Rotor Boot Cone Part 3
Well the north winds are back so I am able to get more work done on the boot cone. Here is the finished mold box:
Those metal angle brackets made it easy to get the corners square and help keep the box sturdy. The duct tape is just to help hold the temporary bottom in place and to help prevent leaks when I pour the plaster.
I used some modeling clay around the edges of the cone. Because the foam block did not have a perfect square edge, some of the plaster would leak under and form an unwanted lip in the mold. Hopefully the clay will give me a nice strait edge. The clay I'm using gets real soft when you heat it, so I used a heat gun to warm it up. It will get hard again when it cools. I'm pretty sure the plaster will stick to the clay so I will have to paint on some liquid mold release before pouring.
Here is a close up of one of the edges. All the wrinkles will in the tape will show up in the mold. Usually you would want to make the part 100% perfect before making the mold because any imperfections in the part will show up in the mold. This, however, is somewhat of an exception because the foam is flexible and there is not much I can do aside from hand carving another boot cone from a different material. I will have to clean up the imperfections on the surface of the mold.
The good thing is that I am using Plaster of Paris which is suppose to be pretty sandable once its dry. I will fill in the gaps with Bondo and sand it smooth so my final composite parts will have a smooth surface finish. And speaking of composites, my buddy Joel hooked me up with a bunch of scrap Carbon Fiber cloth so my first part or two will be Carbon Fiber. That's way over kill for what I'm doing, but what the heck, I won't have to buy cloth to get me started. I will have to buy some epoxy though. I just checked on the stuff that I have had sitting for several years in my garage and there is no way that stuff is going to work.
I'm seeing north winds for tomorrow too, so I should be able to get some more work done.
Those metal angle brackets made it easy to get the corners square and help keep the box sturdy. The duct tape is just to help hold the temporary bottom in place and to help prevent leaks when I pour the plaster.
I used some modeling clay around the edges of the cone. Because the foam block did not have a perfect square edge, some of the plaster would leak under and form an unwanted lip in the mold. Hopefully the clay will give me a nice strait edge. The clay I'm using gets real soft when you heat it, so I used a heat gun to warm it up. It will get hard again when it cools. I'm pretty sure the plaster will stick to the clay so I will have to paint on some liquid mold release before pouring.
Here is a close up of one of the edges. All the wrinkles will in the tape will show up in the mold. Usually you would want to make the part 100% perfect before making the mold because any imperfections in the part will show up in the mold. This, however, is somewhat of an exception because the foam is flexible and there is not much I can do aside from hand carving another boot cone from a different material. I will have to clean up the imperfections on the surface of the mold.
The good thing is that I am using Plaster of Paris which is suppose to be pretty sandable once its dry. I will fill in the gaps with Bondo and sand it smooth so my final composite parts will have a smooth surface finish. And speaking of composites, my buddy Joel hooked me up with a bunch of scrap Carbon Fiber cloth so my first part or two will be Carbon Fiber. That's way over kill for what I'm doing, but what the heck, I won't have to buy cloth to get me started. I will have to buy some epoxy though. I just checked on the stuff that I have had sitting for several years in my garage and there is no way that stuff is going to work.
I'm seeing north winds for tomorrow too, so I should be able to get some more work done.
posted by David Aldrich at
9:41 PM
1 Comments:
You may still be able to use the Epoxy you have stored. They can be used way longer then the manufacturer says. Even if it crystallizes out just warm it up a little. This isn't a structural part, so I wouldn't hesitate to give it a try. Just make a little test part to not waste too much cloth. The only thing I'd watch out for is Tg on your Epoxy. But you know all about it I'm sure.
By
Holger Selover-Stephan, at 9:57 AM
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