gramaton cleric wrote:
well what kinda of stuff are you blanking on, i'll help with design but the art i'll leave to you.
Well, here's a quick history.
First Nosecone (NC) blank attempt (could also be called a positive) - Manta Mark I.
Used Papermache to build a hollow cone and then used plaster to bulk it up to the right proportions. It failed. Reasons
On something this size, you need plaster to be at least 1 inch thick - and I had to quite when the blank hit 45lbs.
Second attempt - Manta Mark II
I used press board and cut it into "ribs" of a nose cone. Imaging the nose of a blimp. If you were looking down on it from above, it would look like a big pie with the ribe being 16 "cuts". Anyways, I filled between the ribs with spray insulation foam and then trimmed it to shape with an electric knife (wish I had pics to show ya - they are in storage - aarrgg). I then skinned the ribs with plaster and then bondo. It looks like it would work - I haven't totally given up on it yet, but the real problem is making it "perfect" - and here is why:
Orginally, I was going to use the NC I made as a jig for Fiberglass. Under these conditions, I would put the glass and resin on the NC and then shape the outside. Once dry, I would pop the jig out and have a hollow nosecone. My father has much more FB expirence than I and told me not to do this. He said, it nearly impossible to get the FB exposed surface right and what I should do is use the NC to make a negative (a mold) and use the negative as the jig. Especially since I need at least two that are nearly Identicle in outside dimentions. The problem is, its almost impossible to get the blank perfect in shape (as I would have discovered if I had followed my original path) - and thats required to mak a good jig. Its turning out to be a lot of work - and one of the worst parts is, that I have no way of "checking" the shape. I may keep at it - but making a near perfect cone is a task. So Mark II is stuck.
Suggestions I have heard:
Use a lathe: Well, I don't have access to one and what would be the material?
Start over and use foam core in "layers" to build a cone that is more perfect than the ribbed one: This is an idea I am pursuing - I already have a program that tells what each layer should be in diameter. Problem is, the layers must be exactly 1/5th of an inch thick - where am I going to find that kind og material??
Vacuum Form it: I could do this - but I don't have a big enough oven or vacuum former - and I don't have a shop to build a large vacuum former.
Any ideas or sugestion? Does the layer method sound good?