|
|
Post by PitYak Studios on Jun 19, 2006 10:50:45 GMT 12
Screw resin! too damn expensive, so I've joined the pplaster brigade, and just got 5kg of Ultracal from TopMark. Top Marks to TopMark for their quick delivery too.
On the drum it says Ratio : 38 parts water / 100 parts plaster.
My question for you Ultracal mavens (I know there at least a couple of you here) is, does that mean parts volume?
and then, is it mixed just like other plasters, sprinkle in the water, stir, pour?
|
|
|
|
Post by c0d3monk33 on Jun 19, 2006 13:06:34 GMT 12
My good man, Ultracal 30 is not just 'plaster'. It's actually a fine blend of Portland cement, silica from the beaches of the mediterranean and the highest quality plaster from Paris. Did you read the data sheets on the USG site? It's actually designed for the tooling prototype industry where high detail and a hard surface are required. As for mixing it I say the devil take measurements. I always mix by feel/eye to a thick pancake mix consistency. www.tabletop-terrain.com/index.php/archives/2005/09/22/460/Is my recipe  |
|
|
|
Post by PitYak Studios on Jun 19, 2006 13:17:32 GMT 12
TopMark call it plaster
|
|
|
|
Post by PitYak Studios on Jun 19, 2006 13:17:51 GMT 12
and who is USG?
|
|
|
|
Post by PitYak Studios on Jun 19, 2006 13:22:16 GMT 12
Ever heard of anyone casting ultracal under pressure? seems a shame to waste my pressure setup
|
|
|
|
Post by c0d3monk33 on Jun 19, 2006 16:14:36 GMT 12
USG is the manufacturer of Ultracal 30, Hydrostone and pretty much any other plaster product you care to mention: en.wikipedia.org/wiki/US_GypsumPressure? I dunno. Plaster setting is an exothermic chemical reaction though so applying pressure might change the setting time? Plenty of people do vacuum casting with Ultracal 30 I believe. |
|
|
|
Post by PitYak Studios on Jun 19, 2006 19:32:21 GMT 12
do you mean vacum de-gassing the plaster mix before pouring? I've never heard of vacuum casting. I'v been looking for a vacuum pump for months to de-gass rtv before pouring. Next batch of moulds I'm going to try setting the rtv under pressure, but i've still got a few wrinkles to get out of my pressure pot first.
|
|
|
|
Post by c0d3monk33 on Jun 19, 2006 20:00:54 GMT 12
Mmmm maybe. My plaster pouring-fu removes most bubbles because it's essentially using the weight of the cement/plaster blend to displace water. By which time the bubbles have already been removed. So I haven't bothered investing in pumps, bell jars (or whatever you use to contain the plaster) etc. Although sure there's not much point degassing the plaster and then pouring it in a normal atmosphere. Surely you're better off pouring the mold and then degassing the whole mess, poured plaster in all? I'm pretty sure that's what I've seen in the HA forums. Ultracal 30 isn't bad at capturing detail, but it's nay resin. Resin is always better at fine detail with the added bonus of being very strong in a small cross section - but of course you pay for that  ... |
|
kreativescenery
Ambitious Upstart
"Life, I don't have a life, I have something better, a family"
Posts: 93
|
Post by kreativescenery on Jun 19, 2006 21:33:39 GMT 12
Hi Phil
You can get Ultracal from the Plaster Warehouse here in Wellie I paid ~$70 for my last sack. I still think I might have a go at making my own Ultracal when I run out of my current supply.
Hi Stu
|
|
|
|
Post by PitYak Studios on Jun 19, 2006 21:51:13 GMT 12
Where's that and how big a sack?
The idea with resin is you degass it before you pour so there are no bubbles in the liquid resin, then cast under pressure to obliterate the bubbles between the resin and the mold that always seem to form in areas of fine detail. I guess you could probably do the same with plaster.
|
|
chris
Ambitious Upstart
Posts: 14
|
Post by chris on Jun 21, 2006 17:20:38 GMT 12
Ever heard of anyone casting ultracal under pressure? seems a shame to waste my pressure setup Would pay to check what the plaster does as it sets. If it expands then there could be trouble. |
|
|
|
Post by PitYak Studios on Jun 21, 2006 17:29:07 GMT 12
I think it shrinks - it doesn't expand as much as resin at least
|
|
kreativescenery
Ambitious Upstart
"Life, I don't have a life, I have something better, a family"
Posts: 93
|
Post by kreativescenery on Jun 21, 2006 19:08:41 GMT 12
Hi Phil
The plaster warehouse is on Thordon Quay I think (Wellington end of the old Hutt Road anyways) you get 25pounds (10kg)
Cheers
Kim
PS are those commandos ready for a game yet? they were looking real good last I saw
|
|
|
|
Post by PitYak Studios on Jun 21, 2006 19:38:35 GMT 12
'fraid not, seems like everyman and his dog wants spears and casts at the minute. I'm trying to find a way to medicaly remove my need for sleep, but the doctors reckon its impossible. I reckon they are being defeatist
|
|
|
|
Post by c0d3monk33 on Jun 21, 2006 20:13:05 GMT 12
Yes Ultracal 30 shrinks. Shrinkage is minimal in my experience but it definitely shrinks as the open faces of my set casts are always slightly recessed from the original pour.
|
|
...
