nathan wrote:thedugan wrote:THAT is the information that I needed. A "foot wide cube" is like 7.48 gallons IIRC....that's a BUTTLOAD of resin, and answers my cost question. Unless the diestones are totally unsuitable for the model in question, I'm thinking that they are much cheaper for the given volume, given what you and Jim have said.
I just want to say that I wasn't being in any way accurate with that foot cube comment. For all I remember, it could have been 9 or 10 inches (though I think it was bigger). That makes quite a big difference once you're working out volume. I'd ask for the dimensions/volume and mix ratios from any seller. Find out exactly how much you're getting in true casting volume.
If it's 6 inches on a side, then it's a bit less then a gallon. A gallon is four times as much as the resin retail. Three quarts is about 39$ - about what I'm paying for 50 pounds of Excalibur sans shipping.
No worries, If it's as big as what you're thinking, then it's WAY better.
It's just a hassle to order and ship it...
As for mix ratios, one reason I picked Excalibur was that it mixes more like plaster does. Only production will tell the tale as to whether or not it will work out volume-wise.
nathan wrote:One of the problems with filling a slush/roto-cast resin piece with plaster is that plaster expands. While not lots, you could get a crack in the resin shell from the pressure. I know time is of the essence for many hobby pursuits, but I'd probably pour the inside of the resin shell in two stages, letting the plaster cure at least part way between the two. My current thinking is to simply fill them with an expanding polyurethane foam or a plaster/die stone with lots of filler to keep the weight down.
And yes, you can slush/roto-cast with die stone and plasters. It just takes a bit of patience. Die stone that sets rapidly is obviously better than plasters that usually take longer. I don't think it would work very well by hand. You'd probably need to build some crazy roto-casting contraption. Or be willing to sit there watching TV rotating a small mould by hand for half an hour. If you get a die stone that is made for quick setting, you could probably get that down to 10 minutes.
You could fill with darn near anything, just mind the resin's brittle nature.
I've actually seen some "crazy roto-casting contraptions" - I'll leave that for later.
nathan wrote:thedugan wrote:Did you do the Hirst Arts thing? Most of the links that folks been putting up are familiar, I've been there before.
Yeah, I did some hirst arts blocks. Took an awful lot of work/time unless you had multiple moulds or made moulds of blocks you wanted in higher quantities. I always thought the Linka approach was better, where you cast wall pieces rather than individual blocks. But that's the wrong scale for me, so I'll have to make my own wall moulds for 10mm/N-Scale buildings.
Done a lot of this? You seem to know a bit about molding....