Question for some of you who have worked with metal

[CelticOne]

I as goofing around the web and located pewter by the pound at http://jas-townsend.com/product_info.php?products_id=202

Now my question is this, what would any of you reccomend for making a mold for said pewter? I know it has a fairly low melting point and as such my father-in-law was suggested using polymer clay, baking it after I had cut out what I wanted in order to make the shape I wanted. My only concern is that it wouldn't hold up to the heat.

Any other ideas would be great or if all else fails maybe someone might have a link or two to someone who could make a mold for me as I'm striking out there too.

Any and all ideas are most welcome, thanks for your time.

[mieljolie]

I don't know much about pewter, but I did some work in casting back in college.  The funnest and most inexpensive molds we made were from cuddlefish (what you buy in the pet shops for birds to sharpen their beaks on).  You just carve your design into the cuddlefish and poor whatever metal you want into the mold.  The texture it produces is very unique.  I made some really nice elephant head pieces.

[Magister]

Phoenix:

  The traditional, and most common method of making moulds for pewter is using soapstone.  It is a fairly soft stone, that can be cut with a handsaw, and worked using common household tools.  Dremels make short work of it.  You can make one, two, or even three piece moulds as you progress in skill.

   It can be purchased online fairly reasonably.  The worst part is the cost of shipping due to weight.  Just do a search on Google, for soapstone suppliers.  You'll find a good dozen, and shop their current specials.  Remember for making a mould you do not need the fancy colors, or whatnot.  The cheapest stuff is fine. 

   A soapstone mould will easily last for thousands of pours if properly cared for.

   If this is not to your liking, there are several types of high-temperature silicone and polymer (rubber) mould making compounds available now.  The issue with these is that it can not be "carved" like soapstone.  But.. if you make a model of what you want out of the pewter from say sculpy, you can use the polymer to make a negative two piece mould for pouring.  Obviously this method is highly preferred if you are attempting to duplicate an item you already have, for example a fancy button, or charm.

   Several of the more popular products are discussed here: http://www.miniaturemolds.com/makeyour.htm

   You can find more information and pricing here: http://www.miniaturemolds.com/rtv.htm

    I have personally used the RTV Silicone very effectively.

     Hope this helps.  Please let me know if you have any more questions.

        - Mag

[mieljolie]

Soapstone for pewter molds.  Wow, I learn something everyday on here.  So, with the low melting point of pewter, you could practically melt it in a home oven or on stovetop, huh?

[groomporter]

IASCO (or the Industrial Arts Supply Company) sells also sorts of casting supplies for pewter, resin and other materials, and they are here in the Twin Cities. http://www.iasco-tesco.com/ Unfortunately they do not take online orders through the website, it's just their catalog online.

[Magister]

newbie:

  Technically yes.  You COULD melt the pewter on a stovetop.  However the question is if you would WANT to.  I know many people who do.. who have a steady enough hand to dip out the pewter, or pour from the whole pot in to their moulds.

  I personally do not.  I also don't consider it safe to recommend to anyone else to do so either.  If you have never had molten metal on your skin.. be VERY glad.  It's like napalm.. it sticks.. it burns.. and it can go right to the bone in a matter of seconds.

    Soooo..  I always recommend that you get some sort of "pot" made for handling lead or pewter.

     I use a Lee production put.  You can adjust the temperature (within reason).. it will hold whatever you don't use (it cools and solidifies).. and it has a handy pour spout, and lever to control flow. 

      This is what I'm talking about: http://www.midwayusa.com/rewriteaproduct/637732

         - Mag

[mieljolie]

Thanks for the info.  That's not a bad price.  I'm always looking for mediums to work in that do not require expensive tools and such.  I like to use things that are commonly available.  I may never try pewter, but it is cool to know it's possible.  I really miss working with metal.

[CelticOne]

Thanks for all the input, it should be very helpful. Now if hubby will let me do it as he's a bit worried I might fry my hands. But it still sounds like something fun to try.

[Hoowil]

I've been doing lost wax casting for a couple years now. I've not worked with pewter yet, but have worked with gold, silver, and bronze, which melt a little higher.

Definitely use a crucible for melting you metals. You can get ones that would work stove top, but I would suggest doing it someplace where accidents are less likely to destroy your house, and using a torch. I'd have to check if a blowtorch gets hot enough for pewter, but we regularly use acetylene to melt our metal.

Get a set of welding gloves and a leather bib, and don't work alone.

For mold making, there are a couple things to take into account. Do you have an easier time carving in relief or in actual form. Carving stone of shell would make great mold, durable, but if you undercut a lip, it may be difficult to get your piece out without breaking the mold. Shouldn't be a problem with a little practice. If you carve in the round, RTV is wonderful stuff. I generally use it to duplicate wax blanks for casting in silicate investment, but the stuff holds up great, and is flexible enough to stretch around uneven surfaces for removal.

Ok, there's my two bits..

[jcbanner]

I would think propane is hot enough. thats what I used when I did lead casting.  I find that those little gas stoves for camping work great for casting metal, you can place them anywhere, and the gas canasters are relatively cheep.  and if the propane stoves don't get hot enough for your taste, I've found that the "white gas" colmen stoves can burn hotter then propane.

[Cormac]

Magister

I had a couple of questions about making molds using RTV.  How do you make a mold for a single sided item?  I would like to make some pewter favors with a flat back.  I assume I would make the detailed side and then simply pour a flat side for the back of the mold.  I was also wonder about how you put the gates in to pour the pewter through.  Do you put something in when making the mold to create the gate or do you cut it after making the mold?  OK I guess I have one more.  With an item with a flat back would it be possible to simply make the mold single sided and pour the pewter into the open back?

Any input would be greatly appreciated.

[renfairpirate]

When i first started making buttons i used the stove top to melt my pewter that lasted about a week. The lee meltig pot is the way to go,check out any gun shops they sometimes have used pot in there reloading stuff. As for molds for a piece with no unercuts i use craft plaster to make molds for small runs of buttons and hatpins         

[Magister]

First the quick response:  Renfairepirate ... those are fantastic!  Amazing work.  I've also used crafting plaster, but found that it's only good for maybe six pours at most.  I've found that if I'm doing a small piece and press the plaster in to a tuna can (empty, and washed of course) before pressing the button or coin in to make the impression it holds up better under the heat, and stress of pouring as well. 

Ok.. now to try to answer Cormacs questions.  I'd like to encourage others to answer too.  I'm certainly not the the final word.. we have so many talented people on here.  Someone might have a better, or just different way to do something.

Let me break your questions out and take each one individually.

How do you make a mold for a single sided item?  I would like to make some pewter favors with a flat back.  I assume I would make the detailed side and then simply pour a flat side for the back of the mold.

In my experience you got it right.  Make a two-piece mould, where one side is just a blank slug impression of the disk / square / whatever.

I was also wonder about how you put the gates in to pour the pewter through.  Do you put something in when making the mold to create the gate or do you cut it after making the mold?

I cheat.  Or well, I at least try to make it as easy on myself as I can.  I've rolled out several "cones", or tornado shaped pieces of sculpy clay in different sizes to fit the size of the mould.  If I don't have one, I roll one out, heat it in the oven until hard, and I'm good to go. 

When pouring the second piece of the mould, place the cone in a non-obtrusive spot in the frame (coated in "no-stick") as not to get stuck in the RTV, but near enough to your item creating the impression as to touch, or very nearly touch and pour your second side.  You now have a funnel spot right there.  Clear any RTV that may block the spout with an exacto knife - being careful not to mark up the actual mould imprint.

With an item with a flat back would it be possible to simply make the mold single sided and pour the pewter into the open back?

Yes... and no.  Yes, you can, and I have in the past.  The devil is in the details, and the detail is usually the level of the surface you are working on.  When the metal is molten it's much like water, so if the one-piece mould is slightly off, the metal will flow to the side creating a finished piece of varying thickness. 

Also, you have the risk of overage.  You need to pour just the right amount to fill the mould, without spilling it over the side and possibly burning your hand, table, floor, cat, whatever. 

Another issue is air bubbles.  When you pour air will get trapped under the molten metal, and will want to "bubble up".  On a one piece that is just laying flat on a table, it will try to bubble up through the piece... and will usually end up setting in the middle of it. 

All in all, in my opinion a one piece mould is not worth the trouble, and risk of injury.  It's not like a clay mould where you press the material in.. this is hot, dangerous stuff you're working with.  Go ahead, spend the 15 minutes, make a blank second piece, and create a spout.  You'll get a better finished product, and you might save your fingers, and your cat in the process.

   Hope this helps.

        - Mag

[Cormac]

Excellent information.  It confirmed much of what I was already leaning towards.  Now I need to get to work on designing a favor.  I'll post my success (or failures) a bit later this winter.