hi all,
this is my first casting project, so any feedback is appreciated! i'm interested in casting a beer bottle shape for a game called polish horseshoes*. a quick search online shows that a typical (US) 330 mL bottle is about 225 mm tall, 58 mm diameter at the base, and weighs around 237 g. while i'm not too particular about the precise shape or reproduction of details, i would like to get the weight fairly close.
still working out the details, but after a bit of reading i think this is a good way to proceed:
- make a solid silicon mould around an empty bottle, probably with a dowel to plug the mouth. cut the mould down the middle to allow removal of the bottle.
- put the mould back together (i assume these will need to be housed in a wooden form). the hole from where the dowel stuck out will allow for filling.
- weigh out proper mixture of polyurethane resin (say, 100 g total) with aluminum trihydroxide filler (the rest, 137 g), and possibly some coloring. pour this mixture into the mould and continuously roll it around.
i have a few concerns though, before i take the plunge and buy materials:
- is polyurethane resin going to be strong enough? since all the materials will drive the cost to around £5 per bottle, it'd be a shame if they just shatter on the first hit. the mixture will be less dense than glass, and therefore the bottle will have thicker walls, so my intuition tells me it might be alright. however, i havent worked with this stuff much, so my intuition may just stink in this case.
- is silicon the best way to go with this? it seems that one of the big advantages to silicon is very good feature reproduction. since there are no real features to reproduce, this isnt a big issue for me. i'd probably need 2 kg to have enough for a bottle (assuming i need 20 mm or so at the thinnest parts of the mould).
- the whole rolling bit might be a pain. i'd have to make a rig for it (or else turn it myself for an hour!) and then i'd be worried that the neck would be very thin or nonexistent. one idea is to plug the top and then i can roll + tilt to cover all sides a bit more evenly. the other option would be to fabricate a core, but then that has to be very precise if i want to hit the weight tolerance. that would also require gluing two halves together, which maybe isnt so bad.
anyway, hoping to get started on this very soon, but thought i'd throw it out for any suggestions from veterans before i take the plunge. thanks in advance for your help!
-p
*the goal of the game is to knock an empty beer bottle off of a pole with a frisbee. i had a place in boston that was already littered with broken glass, but now that i've moved i need to find something a little more park friendly (ie, doesnt occasionally explode into hundreds of tiny sharp fragments). there's not a ton of info about this game that i've found online, so i can post more elaborate rules for any who are curious!