Nosecone Mold?

[jim fustini]

Is there any reason why you can't make a nose cone mold out of Kiln fired/ glazed ceramic? I was thinking if you made a two part mold thick enough to hold it's shape, (Using a "4 to "7.50 plastic nosecone to make the mold) Then using fiberglass/ epoxy to make the nosecones. What problems might I run into?
Distortion of the mold. shrinkage. ect, I don't know anything about ceramics.

[hornet driver]

Really not a bad Idea but your putting in a bit of extra work. Typically you could make a two piece mold(female) and put the part you want to mimic inside(male)--pour in some plaster and let dry. Split the mold--finish the inside of both mold halfs to take out any imperfections and paint with a superior paint---I use AUTOMOTIVE -when finished coat inside of mold with release agent-- apply glass--clamp together--let dry---With a nose cone it might be a good idea to blow up a balloon inside to hold the shape a push out unneeded resin-- building the molds are really the most time consuming part but you'll never need to buy another cone--and you can sell them too!!

[Handeman]

I've never used ceramics, but don't you have to fire them. I know they change size/shape during that process. I think it would be hard to keep the two halves sized right and aligned during the firing process.

The other draw back I see with ceramic is that they are fragile. If you have to pry your part out, I would think the ceramic would break before the fiberglass part. If you happened to drop one half, you're done.

[jim fustini]

I've never used ceramics, but don't you have to fire them. I know they change size/shape during that process. I think it would be hard to keep the two halves sized right and aligned during the firing process.

The other draw back I see with ceramic is that they are fragile. If you have to pry your part out, I would think the ceramic would break before the fiberglass part. If you happened to drop one half, you're done.

That is why I stated "If you make them thick enough" the two parting halves of the mold could be 2 inches thick. And glossy type fired ceramic paint is as slick as you can get. Sprayed with a release agent I don't think that would be an issue. That why I said Kiln fired ,to get the the hard slick surface. I have some ceramic pottery from my niece, she made in a class. They charge about $10.00 per object to make whatever pots, bowls, scuptures.

[gpoehlein]

I dunno - my family did ceramics for a LONG time (my aunt still has a ceramics shop). But I'm kind of thinking that it just isn't the best material for the job. Our local Hobby Lobby sells a number of Alumalite products, and I'm thinking that using something like that (RTV two part mold, then slush cast resin nose cone) is probably the best way to do it.

You might be able to pour a mold using slip (liquid clay), but if the piece is very thick, I don't know if it will completely dry inside. And if it isn't fully dry, I'd be concerned about it firing properly - at best you just won't get a good strong piece, at worst, the moisture inside vaporizes and the piece will explode in the kiln. Same thing happens if there is any air pockets inside (that risk is minimized using slip).

So for resin casting nose cones, I think an RTV mold would really be your best bet. However, I can see this idea, if you could make it work, being useful for something like a home made blow-mold machine. Ceramic molds, once fired and glazed could be pretty tough, and the heat-insulate properties of ceramic are well known. For a small home workshop blow-molder, this might be a viable alternative to cut steel molds.

[Micromeister]

I'm with Greg:
The Better 2/3rd is greatly into Ceramics, and we've talked about similar things for other projects. while most Ceramics or even denser porcelain clays can be size and shape controlled unless the walls are poured very very thick such molds would be subject to chipping and damage during seperation.

RTV silicone rubber is a much better choice and fairly easy to use Mold making material that while not as permanent as a fired ceramic can last a good long time if kept in airtight double baggies
Resin cast, even slush hollow resin cast nose cones it's really the only way to go, other then vacuum forming...a whole nother level LOL!!!

[mkadams001]

It is fairly easy to make a fiberglass mold. There are some great how to videos on u tube and Fiber Glast has some great videos. http://www.fibreglast.com/category/Learning_Center