If its for buildings you

If its for buildings you don't need much of it.  You can order hydrocal through Woodland Scenics or have your hobby store order it in.   http://woodlandscenics.woodlandscenics.com/show/Item/LWHDCL/page/1

Try this supplier

From ebay:

http://www.ebay.com/itm/HYDROCAL-RAIL-ROAD-PLASTER-CEMENT-20-Lbs-for-24-FREE-DELIVERY-/161244771901?pt=Model_RR_Trains&hash=item258aeff63d

Tom

by the bucket

There is a vender on line called the plaster guy. I got a bucket full shipped to my home. Try plaster.com. The shipping costs are horrendous.

Try Here

Multiple varieties of setting-type plasters will work.  Try the USG site listing the available kinds as well as ways to order or find a local supplier (if available)  http://plaster.com/ ,

Presto Patch and Webpatch 90

I have used floor levelers like Presto Patch and Webpatch 90. They have the same formulas as Hydrocal, plaster of paris and silca.

Harold

I've used a mix called

I've used a mix called cornice cement here in oz.

Mainly because it is very strong & does not powder on the surface, when it dries.

Thanks

Ok I have a bit more research to do and experimenting. Presto Patch I think I have seen.

I came across a discussion on MR's discussion boards about the difference between Hydrocal and plaster of paris. Hydrocal is a lot stronger so the formula can't be the same although it can have the same ingredients in it the ratio is probably different. One of the ways that different companies can put out the seemingly same product but not quite?

Jack

Try DuroBond

I wouldn't ever pay for the hobby versions of either plaster or plaster cloth.  Plaster cloth can be found on eBay or elsewhere (medical supply clearances, etc).

For rock casting, I used Durobond-45, which is only about $10 per 25 lbs at Menards.  For a finishing layer over plaster cloth, I use StructoLite - about $12 per 50 lbs.

I've got lots of photos and details of using both on my blog site:

http://rgsrr.blogspot.com/

Just go to their website and

Just go to their website and find the closest distributor.  Russ

http://www.usg.com/content/usgcom/en/products-solutions/products/industrial-specialty/art-&-statuary/hydrocal-white-gypsum-cement.html

Amazon.com

Amazon sells it with free shipping.  Hydrocal is $11.99 for 104 cu. in. container and "PerfectCast" casting material is $8.40 for a 2 lbs. bucket.  Delivered with Prime account.  

plaster

I get Ultracal and casting plaster from a local pottery supply place.

There has to be some give and take here...

The suppliers and costs has been discussed to all ends.  Now I want to try to turn this discussion somewhat.  Of all the products mentioned here which ones produce the smoothest and lightest weight rocks?  Think of it for use on a model railroad that is moveable.  We want to avoid as much weight as we can and we want to avoid as many bubbles in the castings as we can.  We want great looking rock castings.

Thanks guy!

Den

Sorry Jack!

I have Hi-Jacked your thread, but I believe it isn't done yet.  We can let this continue.

Den

Not an issue Den

I am curious my own self on that issue also. One of these days I will be including some rock casting of my own. I am interested in structure walls at the moment.

One thing that crossed my mind while fruitlessly checking the shelves at Lowes and Home Depot was this, There is all sorts of patch material and some of that stuff is pretty light weight and premixed. So could it be used for rock castings if it was watered down and poured in?

I tried this to a certain point with DAP's Fast 'N Final lightweight spackling. I have been working on a couple of grade crossings and on one it didn't want to spread out or become smooth, so out came the spray bottle of water and a couple of squirts and wow what a difference. Just enough water to make it workable sort of like clay.

Have no idea about strength for a casting though.

Jack

patching materials

I think are mostly "drying" type of products.  They harden by losing moisture.  I think for casting applications, a "setting" type of material which hardens chemically would be far superior.  Hydrocal, molding plaster, and dental casting plaster would fill the bill for fine grain molds.  Structolite, Gypsolite, Durabond are coarser grain, less desirable for molds but may be fine for base, quick setting work.

50# bag of Hydrocal for

50# bag of Hydrocal for $22.75 purchased locally at http://www.sterlingsupply.com/.

Check the site out and find a similar place in your local area. Far cheaper than anything else mentioned, especially with shipping.

I hear a lot of hobby shops and art stores buy these bags and repackage them in 1 lb boxes and sell them for 5-10 bucks.  Not a bad markup!

Walt

I have used the US Gypsum.....................

...................hydrocal plaster in the 50 lb bags and also the Woodland Scenics "lightweight" type in the paper carton.  The WS is much lighter than the USG so if weight is a concern, use it even though it is pricier.  Foam is a lot lighter than cardboard and paper towel with plaster but much pricier to do the same size area.  You have a tradeoff.  Light weight=higher cost.

Thanks,

Peter