Casting/Model Makers

[Watercolorchild]

You never know what you will learn until you search something that interests you. I am looking into custom making props. However I can't find a lot of information in regards to casting materials.

I want to make a prop replica, but to sculpt it in soft materials, then cast in a harder one is where I get stuck. Are resins a good alternative to metal casting?
I've thought about metal casting, but it hard to find tutorials in small sizes instead of large sizes. and then there is how to make molds.

Any suggestions would be great. I've seen casting kits at hobby lobby, but they are not really for what I want to cast which is things like ...a belt buckle.

and yes, I'm a N00B. Your patience is appreciated. If this shouldn't be posted here, please let me know.

 

[tonykch]

If you haven't found information on casting materials, you haven't searched long.

Not only will you find a plethora of information about it here, but there are videos all over Youtube that outline the process and different materials. I'd suggest getting in contact with Brick in the Yard Mold Supply or Smooth-On; they'll be able to answer a lot of your questions. If you need links to their websites, I'd suggest Google.

 

[Watercolorchild]

I'm sorry if I wasn't too detailed with my research.
I have done a bit of it, but here is where I get stuck.
I like "Return to Oz" and want to make 2 keys. The "OZ" key, and the "Mombi" Red Key.

I've researched metal casting, but the tutorials I have found makes it look highly dangerous dealing with metals, plus I can't figure what kind of mold to make because all the sand molds don't last past one cast.

Jewelry casting that I looked up is too small...and again there is the danger of fire.

So I thought I would work with a softer material, sculpting with clay and casting with foam, but I really like the feel of heavy keys and didn't know if there was a way to cast in metal on a smaller scale safer. Or I could just use resin.

Anyway, I didn't know if anyone here had tried smaller scale products in metals and if there was any advice anyone could give.

If you haven't found information on casting materials, you haven't searched long.

Not only will you find a plethora of information about it here, but there are videos all over Youtube that outline the process and different materials. I'd suggest getting in contact with Brick in the Yard Mold Supply or Smooth-On; they'll be able to answer a lot of your questions. If you need links to their websites, I'd suggest Google.

 

[Jaded Monk]

Maybe I've had a lousy week and I'm trying to balance it out. Maybe I just feel like playing good samaritan. I don't know.

In order to cast in metal it has to be melted. That means fire. ... or an induction furnace and I think its safe to say that is out.

Very dense and unforgiving compounds do exist for multiple casts of metal from the same mold, not the silicone most of here use, but honest to goodness rubber. It bares more similarity to a tricycle's tires.

You can get the -appearance- of metal with what is commonly referred to as cold casting. The RPF really is saturated with useful information on this subject, as is you tube, but I will give you a couple of leads. Smooth-On (it is a manufacturer, not a material.) Has several videos on their own website about cold cast additives. Powders which are dusted into a mold and mixed into the resin. After curing and buffing they give the appearance of metal, with the exception of weight. Also check out "Brick in the Yard" on you tube. I don't agree with everything he says but it should answer your questions.

If you are dead set on casting in metal, you will have to pay for it. There isn't any (conventional) way around it. There is usually a local foundry or two that will work with you.

Best of luck.

 

[Watercolorchild]

Sorry you had to have a bad week to get it but I appreciate your help!
And I realize I haven't even reached the tip of the iceberg with this site! There are already Oz key casters here and a lot of resources to read through.
I will try to be patent and read more before asking silly questions. LOL

Maybe I've had a lousy week and I'm trying to balance it out. Maybe I just feel like playing good samaritan. I don't know.

In order to cast in metal it has to be melted. That means fire. ... or an induction furnace and I think its safe to say that is out.

Very dense and unforgiving compounds do exist for multiple casts of metal from the same mold, not the silicone most of here use, but honest to goodness rubber. It bares more similarity to a tricycle's tires.

You can get the -appearance- of metal with what is commonly referred to as cold casting. The RPF really is saturated with useful information on this subject, as is you tube, but I will give you a couple of leads. Smooth-On (it is a manufacturer, not a material.) Has several videos on their own website about cold cast additives. Powders which are dusted into a mold and mixed into the resin. After curing and buffing they give the appearance of metal, with the exception of weight. Also check out "Brick in the Yard" on you tube. I don't agree with everything he says but it should answer your questions.

If you are dead set on casting in metal, you will have to pay for it. There isn't any (conventional) way around it. There is usually a local foundry or two that will work with you.

Best of luck.

 

[drknotter]

If you're looking for metal cast of something the size of a key, I would actually suggest getting it 3D printed. Yes, you can 3D print in metal these days. You'd have to either find a model online, or create your own model, but beyond that you just send the file to a professional 3D printing service like Ponoko or Shapeways. Check out their galleries and you can get an idea for the kind of stuff that's possible with 3D printed metal.

Keep in mind though that 3D printed metal objects tend to be more pricey than their plastic counterparts. But if it's something relatively small like a key, I'd say it's worth it. Hope this helps.

 

[arrowguy]

I will back what Jaded said about Smooth-On (if you decide to go that route). We use their foam and resin products in our fx shop for creating theme park animatronics. Great stuff, just takes practice.

 

[NormanF]

Around the start of the year I went to a molding seminar by the local SmoothOn distributor. They talked about two items that might help you. One was a powder that you coat the inside of the mold with and then pour in the resin that simulates metal. The other was actual powdered metal you mix into the resin and then pour. The problem with the powdered metals is that the weight can cause the particles to settle before the resin sets.

Sent from my Etch-A-Sketch

 

[Zarancorde]

Pewter and plaster. Pewter melts at a low temp(>500 degrees) so you could melt it on your stove top in an old pot you weren't going cook with again. plaster, while heat sensitive, will take a few castings before disintegrating.

 

[Beaker]

Low melt white metals exist as does low melt pewters (<600F)
We have Mold Max 60 that can handle up to 560F: http://www.smooth-on.com/tb/files/MOLD_MAX_60_TB.PDF
Casting Pewter Into Mold Max® 60
Or any platinum silicone can handle up to 450F without issue, such as the easy-to-use Mold Star line:
Mold Star® 15, 16 and 30 Platinum Silicone Product Information
Hope this helps

 

[Greg in MO]

@Watercolorchild : The last two posters are on the right track.

Here is some more detailed info from a post I made elsewhere. Some of it may not pertain to your keys, but it may.

Your keys will be metal, and they will be heavy (the tin / bismuth density is bit more than steel). This special metal is not hard to melt (stovetop in uncoated steel or aluminum pot) and since it melts around 320 degrees F it can be cast in silicone or plaster molds.

Just remember that it will re-melt if it gets to 320 again - so don't accidentally lay your key on the woodstove :cry

For your item a flexible silicone mold could be made, and then a metal cast of low melting temperature Tin / Bismuth can be made in it. Multiple casts actually. Here is a link to the material - I recommend the 281-338 (check out the shrinkage data also - virtually zero)
Bismuth Alloys, Cerro Alloys

Due to the complex detail on your item, I suggest the silicone be poured in one piece around the item and then be slit with a razor knife just enough to allow the master to be removed.

Color: There are various ways of putting a patina on this metal. or it can be painted. This metal has no lead so can be safely cast and handled.

 

[Jaded Monk]

Pewter and White metal are very brittle in narrow diameters. If this pewter key is dropped, expect it to break. Additionally, pewter and white metal always look like exactly that. Pewter or white metal. Odd choice of materials for a key.

Cold casting was suggested because it is a more cost effective and practical solution.

Still, its your project, and your milage may vary.

Thomas