Spherical Mold...

[chroniccodez]

How difficult would it be to create a spherical mold about 18-24" in diamater? I need two half spheres for casting an acrylic mold (i know this is for metal casting but i figured the technique is some what the same). I have an acrylic sphere that is the exact same diamater for what I need, but it is two brital when cut in half.

Is this something that I could do myself? If not, should I pay to have a mold made? How much do you think it may cost if I did have it made? I know this is hard to determine, but can anyone give me a general idea like $100-$200. I have a very low budget for my project.

Oh btw, the sphere needs to be hollow.

[keebler303]

does the mold need to be metal?
If not, use fiberglass. You can use your acrylic sphere as a pattern, coat it with a release agent, and make a mold off of it.
Any glass shop could do this easily or I can give more information on how you would do it if you want to do it yourself.

Matt

[chroniccodez]

Forgot to mention that I want it to be casted w/ an acrylic mold. I haven't done any calculations yet, but the walls will need to be 3/4-1" thick around the sides. I would also like the inside to have molded brackets. I do not know the technical term for this. I will be fastening aluminum inside the case.

I would prefer to do it myself, is this feasible? Any suggestions? I have never casted anything before so if you know of any helpful sites please link'em. Thank you.

[ltmquik]

This sounds like a perfect application for rotomolding. You can have a mold cast using aluminum and then finish machine the detail for your shere. This is probably going to cost you between $12k-$30K. I hope you are wanting to make more than one.

[tobyaxis]

Originally Posted by chroniccodez How difficult would it be to create a spherical mold about 18-24" in diamater? I need two half spheres for casting an acrylic mold (i know this is for metal casting but i figured the technique is some what the same). I have an acrylic sphere that is the exact same diamater for what I need, but it is two brital when cut in half. Is this something that I could do myself? If not, should I pay to have a mold made? How much do you think it may cost if I did have it made? I know this is hard to determine, but can anyone give me a general idea like $100-$200. I have a very low budget for my project. Oh btw, the sphere needs to be hollow.

Just a Soild CAD Model or the Actual Sphere.

I'll do a CAD Model for you for $50.00 US. The Actual Part will cost a lot more than that.

[spider]

i'm not sure....would 3d printing work???

[chroniccodez]

Originally Posted by ltmquik This sounds like a perfect application for rotomolding. You can have a mold cast using aluminum and then finish machine the detail for your shere. This is probably going to cost you between $12k-$30K. I hope you are wanting to make more than one.

...yeah I do not have that sort of budget

[DSL PWR]

Do you need a solid sphere or 2 domes? If you need domes use a vac press like they have on mythbusters and do one half at a time.

[chroniccodez]

Originally Posted by DSL PWR Do you need a solid sphere or 2 domes? If you need domes use a vac press like they have on mythbusters and do one half at a time.

I need two domes that when placed together, create a perfect sphere. I love mythbusters, but I can't remember the vac press. Will I be able to make a perfect sphere?

[holbieone]

what tolerance are we talking here ?

[chroniccodez]

Tolerance?

diameter: 18-24"
thickness: approx. 1"

[holbieone]

Originally Posted by chroniccodez Tolerance? diameter: 18-24" thickness: approx. 1"

what tolerance on roundness

also do you have any pics or drawings of what you want to mold
or is this what you want to mold