Fibreglass hollow spheres

[Davethebuilder]

Hi, I'm working on a project and have done a lot of experimenting with fibreglass but am not satisfied with the results so far.

What I need are some moulded hollow fibreglass balls of various sizes but I couldn't find any manufacturers apart from Christmas decorations.

As I will be needing various sizes balls I thought I would research and see if it would be viable to make them myself... Ideally the balls would be smooth outside so I believe they would have to come out of a mould... I'm new to fibreglassing but I believe there is a type of resin/glass mix that is cooked in an oven and maybe I could combine that idea with a mould... Any help would be greatly appreciated. Dave

[yurvalentine]

Yikes. Best bet is to use some kind of rubber ball (like a dog toy) and make two halves, then adhere them and possibly add a second layup, though if they are put under much stress it will likely delaminate.

As for oven curing, you can cure just about any type of resin you want with heat. With polyester it's generally a good idea to let it cure for a day at room temperature, and then post cure it in an oven. Usually 150-200F for several hours will get you the best results (it mostly helps with stiffness)

[Davethebuilder]

Yeah, kind of hoping for something with a faster curing time so that multiple balls can be made ... A few seconds maybe?

[yurvalentine]

SMD Sunflash then. Oven curing is 3hrs minimum for all resin types I know of.

[Davethebuilder]

Oh... But it would have to cure inside the mould, where there's no sunlight... Just wondering if the mould could be made of clear plastic and if so would it still work with sunlight?... Alternatively, artificial uv light inside of a mould??... I'm kind of thinking that the mould would have to be either rotated as the resin cures or pressurised... Any ideas as to how they make the fibreglass Christmas ball decorations? Thanks so far

[KiKaZz74]

Lay over a foam ball like for crafts. Let it cure one layer at a time. Cut it in half when you are done.

[SnowDrifter]

Could you use a balloon or maybe the bladder out of a soccer ball or something? Glass over, deflate, then remove?

[Davethebuilder]

Just thinking about the Christmas balls... From memory some were like a thin glass and others were a foam ball wrapped in some type of material which might be glass fibre... I need it to be smooth and uniform on the outside though, so some kind of a mould would be needed.

[yurvalentine]

Oh... But it would have to cure inside the mould, where there's no sunlight... Just wondering if the mould could be made of clear plastic and if so would it still work with sunlight?... Alternatively, artificial uv light inside of a mould??... I'm kind of thinking that the mould would have to be either rotated as the resin cures or pressurised... Any ideas as to how they make the fibreglass Christmas ball decorations? Thanks so far

In the industry I imagine they would use a 3 piece mold, one center ball and two outer pieces that you can bolt together to get some pressure on the layup. But unless you have access to a machine shop that won't be easy at all. If it were me I would skip the outer mold and just use a ball to get the inside round, then be very careful about how you lay the glass. Generally in the pro industry they would have the specially woven pieces which makes things a lot simpler.

[never knows best]

get a Styrofoam ball from a crafts store and cover with as many layers of fiberglass needed. let cure then cut/drill a hole the size of the driver needed. use acetone to dissolve the Styrofoam ball. your left with a spherical "pod"